1 GOALS AND OBJECTIVES OF METROLOGY, STANDARDIZATION AND CERTIFICATION

Metrology, standardization, certification are the main tools for ensuring the quality of products, works and services - an important aspect of commercial activity.

Metrology- this is the doctrine of measurements, ways to ensure their unity and ways to acquire the required accuracy. The key point of metrology is measurement. According to GOST 16263–70, measurement is finding the value of a physical quantity using special technical means experimentally.

Main tasks of metrology.

The tasks of metrology include:

1) development of a general measurement theory;

2) development of measurement methods, as well as methods for establishing the accuracy and precision of measurements;

3) ensuring the integrity of measurements;

4) determination of units of physical quantities.

Standardization– an activity aimed at identifying and developing requirements, norms and rules that guarantee the consumer’s right to purchase goods at a price that suits him, of proper quality, as well as the right to comfortable conditions and labor safety.

The single objective of standardization is to protect the interests of consumers in matters of quality of services and products. Taking the Law of the Russian Federation “On Standardization” as a basis, standardization has the following tasks and goals, as: 1) harmlessness of works, services and products for human life and health, as well as for the environment;

2) the safety of various enterprises, organizations and other facilities, taking into account the possibility of emergency situations;

3) ensuring the possibility of replacing products, as well as their technical and information compatibility;

4) the quality of work, services and products, taking into account the level of progress achieved in technology, technology and science;

5) careful treatment of all available resources;

6) measurement integrity.

Certification is the establishment by the relevant certification bodies of providing the required assurance that a product, service or process conforms to a specified standard or other normative document. Certifying authorities may be a person or body recognized as independent of either the supplier or the purchaser.

Certification is focused on achieving the following goals:

1) assisting consumers in making the right choice of products or services;

2) protection of consumers from low-quality products of the manufacturer;

3) establishing the safety (hazard) of products, work or services for human life and health, the environment;

4) evidence of the quality of products, services or work declared by the manufacturer or performer;

5) organizing conditions for comfortable activities of organizations and entrepreneurs on the single commodity market of the Russian Federation, as well as for taking part in international trade and international scientific and technical cooperation.

2 OBJECTS AND SUBJECTS, TOOLS AND METHODS OF SCIENCE

Object of standardization is an item (product, service, process) subject to standardization.

Main tasks standardizations are:

1) ensuring mutual understanding between developers and customers;

2) establishing requirements for the range and quality of products based on standardization of their quality characteristics in the interests of the consumer and the state;

3) unification based on the establishment and application of parametric and standard size series, basic structures, structurally unified block-modular components and products;

4) establishment of metrological norms, rules, regulations and requirements (metrology is the science of measurements and dimensions);

5) development and establishment of metrological standards and requirements for technological processes;

6) creation and maintenance of classification and coding systems for technical and economic information;

7) regulatory support, assistance in implementing the legislation of the Russian Federation using standardization methods and means.

Basic principles standardizations are as follows:

1) the development of regulatory documents on standardization should be based on the consideration and analysis of such factors as product quality, its cost-effectiveness, compatibility, safety, necessity, etc.;

2) as a priority, standards should be developed that contribute to ensuring the life and health of people, the safety of property, environmental protection, ensuring the compatibility and interchangeability of products;

3) the fundamental factors in the development of standards should be the mutual consent of the parties involved, compliance with legal norms, etc.;

4) standards should be developed so that they do not create obstacles to international trade. When developing standards and technical specifications, projects should be taken into account and the standards of international organizations, as well as, if necessary, national standards of other countries, should be taken into account.

Standardization uses various methods, How general scientific, so and specific. TO general scientific methods include the following:

1) observation;

2) experiment;

3) analysis;

4) synthesis;

5) modeling;

6) systematization;

7) classification;

8) methods of mathematics, etc.

Main specific methods standardizations are unification, ranking, restrictions, selection, simplification, typification, borrowing, aggregation.

3 HISTORY OF THE DEVELOPMENT OF STANDARDIZATION, CERTIFICATION AND METROLOGY

Metrology (from the Greek words “metron” - measure and “logos” - study) began to develop as a science in 1949, when scientific work appeared PetrushevskyF. AND. " General metrology" parts 1 and 2, St. Petersburg.

The first Decree on standard calibers was issued in 1555 during the reign of Ivan the Terrible.

Under Peter I during the period of his revolutionary reforms standardization has been widely developed:

1) standard houses began to be built in Moscow;

2) a division of guns into three types was introduced - cannons, howitzers, mortars;

3) a Decree was issued on the production of shotguns and pistols in a single caliber (one caliber for shotguns and another caliber for pistols). Since the middle of the 19th century, with the development of all

branches of the Russian economic complex (including water and railway transport), the role of standardization was constantly increasing, in particular, uniform standard requirements were introduced for combustion boilers, metal pipes and small metal products - fasteners (bolts, screws, nuts, rivets, etc.). Standardization in Russia received its greatest development after 1917. In 1918, the Council of People's Commissars (SNK of the RSFSR) issued a decree “On the introduction of the international metric system of weights and measures in Russia.” In 1925, by order of the Council of People's Commissars, the first standardization committee was organized under the Council of Labor and Defense. The first standard OST1 “Wheat, breeding grain varieties, nomenclature” was developed in 1926 and published on May 7 of the same year. In the USSR in the 1930s. Other standards for the main types of products were developed and published, and in 1940, by order of the Government, the All-Union Committee for Standardization was founded. In the same year, a decree of the USSR Government was published “On liability for the release of substandard products and for non-compliance with standards; at the same time, all-Union standards (OSTs) were translated into GOSTs with the addition of a serial number and year of approval. In 1965, two institutes were formed: the All-Union Scientific Research Institute for Standardization (VNIIS) and the All-Union Information Fund for Standardization (VIFS). In 1992, the GOST mandatory certification system was introduced in Russia, and the Law “On the Protection of Consumer Rights” was adopted. In 1893, a scientific metrological organization was created in our country, great merit in this area belongs to D. I. Mendeleev, who assessed this science as a kind of powerful lever of influence on the economy.

Currently, the Federal Agency for Technical Regulation and Metrology operates in Russia, and the Law of the Russian Federation of April 27, 1993 “On Ensuring the Uniformity of Measurement” is in force, regulating metrological norms and rules.

4 BASICS OF MEASUREMENT THEORY

The theory of measurement has deep historical roots - more than two hundred years ago, the great mathematician of that time L. Euler gave a clear definition of the concept of “measurement”: “It is impossible to define or measure one quantity otherwise than by taking another quantity of this tetrode as known and indicating the ratio in which it is to it.” The theory considers measurement from three points of view of the scientific approach: technical, metrological and epistemological.

Technical side measurement consists of a set of operations for the use of technical means.

Metrological essence measurement consists of comparing (explicitly or implicitly) the measured physical quantity with its unit (stored by the means used), the size of which is transferred from the standard or reference measuring instrument.

Epistemological aspect This theory says that the purpose of measurement is to obtain the value of the measured quantity (in a form convenient for further use) with a known error, which in many cases should not exceed the established limit. Measurements, covering all spheres of human activity, represent the most important means of obtaining the most objective measurement information.

In understanding the material world around us, quantitative estimates are of great importance, which make it possible to reveal the patterns operating in nature, take into account material resources, and determine the amount of all kinds of products or one or another human activity.

At the same time, without improving the quality of measurements, scientific and technological progress is currently impossible in almost any area of ​​human activity. In addition, without reliable measurement information, it is impossible to control complex technological processes, spaceships and other moving objects, or successfully develop microelectronics and automatic production. Increasing the accuracy of measurements when accounting for raw materials, agricultural products and other material assets leads to significant savings in their transportation, storage and consumption, and all this is very important in a market economy.

The correct diagnosis of diseases and the effectiveness of treatment of patients depend on the quality of measurement information in medicine. In science, increasing the accuracy of measurements often leads to major and very important discoveries. There is a direct direct connection between the quality of measurements and the quality of manufactured products.

5 VERIFICATION AND CALIBRATION OF MEASURING SYSTEMS

In accordance with GOST R 8.596–2002, they are subjected to verification IC measuring channels, which are covered by a type approval certificate, subject to application or applied in the areas of state metrological control and supervision:

1) IS-1 – initially upon release from production or repair, upon import and periodically during operation. The need for initial verification of IS-1 measuring channels after installation at the facility is determined when the IS-1 type is approved;

2) IS-2 – initially during commissioning into permanent operation after installation at the facility or after repair (replacement) of IS-2 components that affect the error of the measuring channels, and periodically during operation.

1) IS-1 measuring channels, as a rule, are subjected to comprehensive verification, during which the metrological characteristics of the IS measuring channels as a whole (from input to channel output) are monitored;

2) IS-2 measuring channels, as a rule, are subjected to component-by-element (element-by-element) verification: dismantled primary measuring transducers (sensors) - in laboratory conditions; the secondary part - a complex component, including communication lines - at the installation site of the IC while simultaneously controlling all influencing factors acting on the individual components. If specialized portable standards or mobile reference laboratories are available and IS-2 inputs are accessible, complete verification of IS-2 measuring channels at the installation site is preferable. If necessary, the permissible values ​​of the metrological characteristics of the measuring channels of the IC or complex components verified at the installation site are determined by calculation using the standardized metrological characteristics of the measuring components for the conditions prevailing at the time of verification and differing from normal conditions.

IC measuring channels that are not subject to use or are not used in the areas of state metrological control and supervision are subject to calibration.

The measuring channels are calibrated by the IS in accordance with PR 50.2.016–94 State system for ensuring the uniformity of measurements:

1) Russian calibration system;

2) requirements for performing calibration work.

6 RULES AND PROCEDURE FOR CERTIFICATION

Certification of products, works, services is the activity of certification bodies, focused on verifying that the product actually meets the requirements specified in the legislation.

Certification is carried out by special bodies for testing laboratories and certification. The certifying organization does not have the right to be a seller, manufacturer or consumer of products it certifies.

Rules for certification.

1. Accreditation activities are carried out by the State Standard of Russia and federal executive authorities based on the results obtained after certification of organizations.

2. Imported and domestic products must be certified based on the same requirements and standards.

3. The applicant has the right to choose between certifying bodies in the event that there are several accredited bodies for certification of the same product.

4. If the certification results are positive, the certification body will issue a certificate and a license to use the mark of conformity.

5. Only after registration of the certificate in the State Register, it comes into force.

6. All documents must be prepared in Russian.

Certification is carried out in a certain order.

1. An application for certification is submitted. The applicant submits an application to the certification body.

The certification body reviews applications and then provides the applicant with a list of authorities and testing laboratories.

2. Sampling and testing. Sampling is carried out by a certification body or testing laboratory. Test reports are provided to the certifying body and the applicant.

3. Production assessment. The certification body analyzes the state of production. The product conformity certificate specifies the method of production assessment.

4. Issuance of a certificate of conformity. The expert's decision is drawn up based on the results of the production assessment. If the conclusion is positive, a certificate is issued, which records the registration number and the reasons for its issuance. If the expert’s conclusion is negative, the applicant receives a refusal with an explanation of the grounds for the refusal.

5. Application of the law of correspondence. The manufacturer receives the right to label products with a conformity mark (if there is a license) from the certification body.

6. Inspection control over certified products consists of periodic and unscheduled inspections with testing of samples. If there is information about claims regarding the quality of products, the certifying body assigns unscheduled inspections. The results of the inspection are documented in a report, which is stored in the certification body.

7. Corrective measures are prescribed in case of inadequate product quality (failure to comply with the rules for using the mark of conformity).

7 MANDATORY AND VOLUNTARY CERTIFICATION

According to a number of legislative acts currently in force in the Russian Federation and, in particular, the Law “On Quality and Protection of Consumer Rights,” mandatory certification of many types of products, industrial and technical purposes, consumer food products, as well as services provided to the population by various enterprises and organizations is carried out. (public or private - forms LLC, CJSC, OJSC, etc.). There is an extensive list of products, goods and services that are subject to mandatory certification, and when issuing a license (permits) for the right to conduct economic or entrepreneurial activities, special bodies take into account the applicants’ certification.

Mandatory certification of technical products, food products and services primarily involves:

1) guarantee and reliability in operation of various types of equipment, including household equipment;

2) high taste and safety of food products for human health;

3) provision of services at a high level of service (in particular, household services in the form of dry cleaning, laundry, haircuts, repairs of television, video, audio equipment, etc.).

Basic building materials used in the construction of residential buildings, industrial buildings, and hydraulic structures (dams, canals, water intakes, pumping stations, etc.) are subject to mandatory certification. Pharmaceutical products in the form of medicinal preparations of various forms (tablets, tinctures, herbal mixtures, etc.) are subject to mandatory certification.

Certification of control and measurement equipment produced by enterprises of the instrument-making industry for various sectors of the country's economic complex is mandatory. Certified control and measurement instruments for various purposes allow you to monitor the manufacturing process and determine the quality of manufactured products and their compliance with state standards. Without reliable information about the quality of measurements of the instruments used (or complex equipment), it is impossible to control complex technological processes, spaceships and stations, as well as other moving objects on the seas, oceans, in the air and on land, or to develop microelectronics and modern high-tech automatic production. From the above, it is clear how important it is to carry out mandatory certification not only for the successful development of the economic complex of our country, but also for ensuring the safe life of the entire population.

PREFACE

Standardization, metrology and certification are tools for ensuring the quality of products, works and services - an important aspect of multifaceted commercial activities.

Abroad already in the early 80s. came to the conclusion that business success is determined primarily by the quality of products and services. 80% of respondents in a survey of 200 large US firms responded that quality is the main factor in selling goods at a favorable price. Hence the conclusion: mastering quality assurance methods based on the triad - standardization, metrology, certification - is one of the main conditions for a supplier to enter the market with competitive products (services), and therefore commercial success.

The quality problem is relevant for all countries, regardless of the maturity of their market economy. Suffice it to recall how in Japan and Germany, defeated and crushed in the Second World War, the skillful use of standardization and metrology methods made it possible to ensure the quality of products and thereby give rise to the renewal of the economies of these countries. Nowadays they often recall the statement of the Russian philosopher and political thinker I.A. Ilyin (1883-1954): “... the Russian people have only one outcome and one salvation - a return to quality and its culture. For quantitative paths have been trodden, suffered and exposed, and quantitative illusions are being eliminated to the end before our eyes.”

Today, the manufacturer and his reseller, seeking to improve the reputation of the brand, win the competition, and enter the world market, are interested in meeting both the mandatory and recommended requirements of the standard. In this sense, the standard acquires the status of a market incentive. Standards for processes and documents (managerial, shipping, technical) contain those “rules of the game” that industry and trade specialists must know and follow in order to conclude mutually beneficial transactions.

Thus, standardization is a tool to ensure not only competitiveness, but also effective partnership between the manufacturer, customer and seller at all levels of management.

Today, it is not enough for a supplier to strictly follow the requirements of progressive standards - it is necessary to support the release of goods and the provision of services with a certificate of safety or quality. The greatest trust among customers and consumers is a certificate for a quality system. It creates confidence in the stability of quality, in the reliability and accuracy of measured quality indicators, and indicates a high culture of processes for producing products and providing services.

In the future, for a number of goods and services, confirmation of compliance with established requirements will be carried out not only through certification, but also by the manufacturer of the product or service provider, i.e., the first party. Under these conditions, the role and responsibility of organizational leaders in the competent application by staff of the rules of standardization, metrology and certification increases.

Compliance with metrology rules in various areas of commercial activity (trade, banking, etc.) allows you to minimize material losses from unreliable measurement results.

The issue of harmonizing domestic rules of standardization, metrology and certification with international rules is very urgent, since this is an important condition for Russia’s accession to the World Trade Organization (WTO) and the country’s further activities within this organization.

So, the country’s transition to a market economy and its inherent competition, the struggle for consumer trust will force commercial specialists to more widely use methods and rules of standardization, metrology and certification in their practical activities to ensure high quality of goods, work and services.

The purpose of studying the discipline “Fundamentals of standardization, metrology and certification” is to develop students’ knowledge, skills and abilities in these areas of activity to ensure the effectiveness of commercial activities.

INTRODUCTORY PART

Ensuring the quality of goods and services as the main goal of standardization, metrology and certification activities

The presentation of this part has three goals: explaining the essence of quality; justification of the need to apply standardization, metrology and certification work to ensure quality (Fig. 1); an explanation of the essence of a number of “cross-cutting” (key) terms (quality, quality indicator, quality control, testing, quality system) used in all three chapters of the textbook and summarized in the ND presented in Appendix 6.

Rice. 1. Triad of methods and activities for quality assurance (22)

1. ESSENCE OF QUALITY AND QUALITY REQUIREMENTS

1.1 The essence of quality

Quality- a set of characteristics of an object related to its ability to satisfy stated or anticipated needs (ISO 8402).

So, the concept of quality includes three elements - object, needs, characteristics. To better judge quality, you need to consider these elements.

Object may be, for example, an activity or a process; products; service, organization, system or individual; any combination of them.

An example of such a combination is such a comprehensive property as “quality of life.” Abroad, and recently in our country, the problem of protecting the interests and rights of consumers has increasingly begun to be considered from the standpoint of quality of life. This concept includes a number of aspects of the process of satisfying human needs: the quality of goods and services, protection of the environment, ensuring physical and moral health, quality of education, etc.

In the future, quality will be considered in relation to such a field of activity as commerce, and to its main objects - products (goods) and services.

Products- the result of activities or processes (ISO 8402).

Product- any thing that is freely alienable, transferred from one person to another under a purchase and sale agreement (GOST R 51303-99 “Trade. Terms and definitions”).

A product is anything that can satisfy a need or need and is offered to the market for the purpose of attracting attention, acquisition, use or consumption.

Service- the results of direct interaction between the supplier and the consumer and the internal activities of the supplier to meet the needs of the consumer (I SO 8402).

There is another definition of a service, given (also according to international standards) in a more accessible form: a set of functions that an organization offers to the consumer (IEC 50).

Let's consider the second element of quality - needs. There is a hierarchy of needs. At the lowest level, these are physiological needs that are satisfied with food; security needs that are satisfied through mandatory certification activities. At a higher level are aesthetic needs and needs for creativity.

In order to compete successfully today in the domestic and especially in the foreign markets, it is necessary to timely anticipate and anticipate the slightest changes in consumer preferences, i.e. you need to know the expected, long-term needs. “The consumer must get what he wants, when he wants it and in the form in which he wants,” this is the first principle of quality assurance formulated by Dr. E. Deming.

Distinguish qualitative and quantitative characteristics. Qualitative characteristics are, for example, the color of the material, the shape of the product. Quantitative characteristics (parameters) are used to establish the area and conditions of use of the product (clothing size, engine power, etc.) and to assess quality.

Level of quality- quantitative characteristics of one or more properties of a product included in its quality (GOST 15467). The quality indicator quantitatively characterizes the suitability of a product to satisfy certain needs. Thus, the need to have durable fabric is determined by the indicators “breaking load”, “abrasion resistance”, etc.

Quality indicators can be expressed in different units and can be dimensionless. When considering an indicator, one should distinguish between the name of the indicator (breaking load, service life) and the value of the indicator (respectively 50 N; 1000 h).

1.2 Characteristics of quality requirements

The most universal, i.e. applicable to most goods and services are the following requirements: purpose, safety, environmental friendliness, reliability, ergonomics, resource saving, manufacturability, aesthetics.

Appointment requirements - requirements establishing: product properties that determine its main functions for which it is intended (productivity, accuracy, calorie content, speed of service execution, etc.), - functional suitability; composition and structure of raw materials; compatibility and interchangeability.

Ergonomic requirements- these are requirements for consistency of product design with the characteristics of the human body to ensure ease of use.

Resource saving requirements - These are requirements for the economical use of raw materials, materials, fuel, energy and labor resources.

Manufacturability requirements- adaptability of products to manufacture, operation and repair with minimal costs and given quality indicators.

Aesthetic requirements - These are requirements for the ability of a product or service to express an artistic image, socio-cultural significance in sensually perceived human forms (color, spatial configuration, quality of finish of a product or room).

In accordance with the Law of the Russian Federation “On Standardization” (Article 7), the requirements established by state standards to ensure the safety of products (works, services) for the environment; life, health and property, to ensure compatibility and interchangeability of products, are mandatory for compliance by government bodies and business entities. Mandatory requirements also include methods for monitoring the compliance of goods with mandatory requirements and requirements for labeling as a method of information about the danger (safety) of the product and the rules for handling the product.

Federal Agency for Education

St. Petersburg State University of Service and Economics

Test

Discipline: “Metrology, standardization and certification”

Completed:

1st year student

Specialty: 0502-u

Kuryashova Svetlana Nikolaevna

Checked:

Kolpino 2009

Introduction

Theoretical part

1. Basic concepts and definitions of metrology

1.1. Classification of measurements

3. Basics of certification

I. Practical part

1. Main types of normative documents on standardization

2. Determining the authenticity of a product using an international European standard barcode

3. Selection and justification of a certification scheme for products and preparation of the necessary certification documents

4. Selection and justification of a certification scheme for the service and preparation of the necessary certification documents

Bibliography

Introduction

The tools for ensuring the quality of products, works and services are standardization, metrology and certification.

For all countries, regardless of the maturity of the market economy, the problem of quality is relevant. To become a participant in the world economy and international economic relations, it is necessary to improve the national economy taking into account global achievements and trends.

Russia's transition to a market economy determines new conditions for the activities of domestic firms, enterprises and organizations, both in the domestic and foreign markets.

The right of enterprises to independence does not mean permissiveness in decisions, but forces them to study, know and apply the “rules of the game” accepted throughout the world in their practice. International cooperation in any area and at any level requires the harmonization of these rules with international and national standards. Standardization, certification and metrology in the form it was in the planned economy not only did not fit into the new working conditions, but also slowed down or simply made impossible the integration of Russia into the civilized economic space.

The Russian Federation Law “On the Protection of Consumer Rights”, “On Standardization”, “On Certification of Products and Services”, “On Ensuring the Uniformity of Measuring Instruments” created the necessary legal framework for introducing significant innovations in the organization of these economically important areas of activity.

Today, the manufacturer and its reseller, seeking to improve the reputation of the brand, win the competition, and enter the world market, are interested in meeting both the mandatory and recommended requirements of the standard. In this sense, the standard acquires the status of a market incentive. Thus, standardization is a tool to ensure not only competitiveness, but also effective partnership between the manufacturer, customer and seller at all levels of management.

Standardization creates the organizational and technical basis for the production of high-quality products, specialization and cooperation of production, and gives it the properties of self-organization.

A standard is a sample, standard, model taken as the initial one for comparison of other similar objects with them. As a normative and technical document, the standard establishes a set of norms, rules, requirements for the object of standardization and is approved by the competent authorities.

I. Theoretical part

1. Basic concepts and definitions of metrology

Metrology (from the Greek metron – measure, logos – study) is the science of measurements, methods and means of ensuring their unity and ways to achieve the required accuracy. The subject of metrology is the extraction of quantitative information about the properties of objects with a given accuracy and reliability. The means of metrology is a set of measurements and metrological standards that provide the required accuracy.

Metrology studies:

Methods and means for accounting for products according to the following indicators: length, weight, volume, consumption and power;

Measurements of physical quantities and technical parameters, as well as properties of the composition of substances;

Measurements for control and regulation of technological processes.

Unity of measurements is a state of measurements in which their results are expressed in legal units and errors are known with a given probability. Unity of measurements is necessary in order to be able to compare the results of measurements taken at different times, using different methods and measuring instruments, as well as in different geographical locations.

The uniformity of measurements is ensured by their properties: convergence of measurement results; reproducibility of measurement results; correctness of measurement results.

1.1Classification of measurements

According to the accuracy characteristics:

Equal-precision measurements are a series of measurements of a certain quantity made using measuring instruments that have the same accuracy, under identical initial conditions;

Unequal measurements are a series of measurements of a certain quantity made using measuring instruments of equal accuracy under identical initial conditions.

By methods of obtaining results measurements are divided into:

Direct – when a physical quantity is directly associated with its measure;

Indirect – when the desired value of the measured quantity is established based on the results of direct measurements of quantities that are related to the desired value by a known dependence;

Cumulative – when systems of equations are used, compiled from the results of measuring several homogeneous quantities.

Joint - produced with the aim of establishing a relationship between quantities. With these measurements, several indicators are determined at once.

By type of change in the measured value:

Static – associated with determining the characteristics of random processes => the required number of measurements is determined by static methods.

Dynamic – associated with quantities that change during the measurement process (t of the environment).

By number of measurements:

One-time;

Multiple (> 3);

By way of presenting the result:

Absolute - (use direct measurement of one basic quantity and physical constant).

Relative - based on establishing the ratio of the measured quantity used as a unit. This measured quantity depends on the unit of measurement used

2. Standardization, categories and types of standards

Standardization is the activity of establishing norms, rules and characteristics in order to ensure:

Safety of products, works and services for the environment, life, health and property;

Technical and information compatibility, as well as interchangeability of products;

Quality of products, works and services in accordance with the level of uniformity of measurements;

Saving all types of resources;

Safety of economic facilities, taking into account the risk of natural and man-made disasters and other emergency situations.

In Russia, the following categories of normative and technical documentation have been established that define the requirements for standardization objects:

State standards (GOST);

Industry standards (OST);

Republican Standards (RST);

Enterprise Standards (STP);

Standards of public associations (STO);

Technical conditions (TU);

International Standards (ISO/IEC)

Regional standards;

Interstate standards;

National standards.

State standards (GOST) are developed for products, works, services, the needs for which are intersectoral in nature. The standards of this category are accepted by the State Standard of Russia. The standards contain both mandatory and advisory requirements. The mandatory ones include: the safety of a product, service, process for human health, the environment, property, as well as industrial safety and sanitary standards, technical and information compatibility and interchangeability of products, unity of control methods and unity of labeling. Mandatory requirements must be observed by government authorities and all business entities, regardless of their form of ownership. The recommended requirements of the standard become mandatory if they are referenced in the agreement (contract).

Industry standards (OST) are developed in relation to the products of a particular industry. Their requirements must not contradict the mandatory requirements of state standards, as well as the rules and safety standards established for the industry. Such standards are adopted by government authorities (for example, ministries), which are responsible for compliance of industry standards with the mandatory requirements of GOST R.

The range of applicability of industry standards is limited to enterprises subordinate to the government body that has adopted this standard. Monitoring the implementation of mandatory requirements is organized by the agency that adopted this standard.

Republican standards (RST) are established in agreement with Gosstandart and the relevant leading ministries and departments for assigned product groups, for certain types of products manufactured by enterprises.

The RST establishes requirements for products that can be produced by enterprises located on the territory of the republic, but are not the subject of state and industry standardization.

RSTs are also established for consumer goods manufactured by enterprises located on the territory of the republic, regardless of their subordination, in cases where there are no state or industry standards for the products.

1. General issues of the fundamentals of metrology and measuring technology

In practical life, people deal with measurements everywhere. At every step there are measurements of such quantities as length, volume, weight, time, etc.
Measurements are one of the most important ways for humans to understand nature. They provide a quantitative description of the world around us, revealing to humans the patterns operating in nature. All branches of technology could not exist without a comprehensive measurement system that determines all technological processes, their control and management, as well as the properties and quality of products.
The branch of science that studies measurements is metrology. The word "metrology" is formed from two Greek words: metron - measure and logos - doctrine. The literal translation of the word “metrology” is the study of measures. For a long time, metrology remained mainly a descriptive science about various measures and the relationships between them. Since the end of the 19th century, thanks to the progress of the physical sciences, metrology has received significant development. A major role in the development of modern metrology as one of the sciences of the physical cycle was played by D. I. Mendeleev, who led domestic metrology in the period 1892 - 1907.
In accordance with GOST 16263-70 “Metrology. Terms and Definitions": metrology is the science of measurements, methods and means of ensuring their unity and ways of achieving the required accuracy.
Unity of measurements- a state of measurements in which their results are expressed in legal units and measurement errors are known with a given probability. Unity of measurements is necessary in order to be able to compare the results of measurements taken in different places, at different times, using different methods and measuring instruments.
Accuracy of measurements characterized by the closeness of their results to the true value of the measured quantity. Accuracy is the reciprocal of errors(discussed below).
Measuring technology is a practical, applied area of ​​metrology.
The measurable quantities with which metrology deals are physical quantities, i.e. quantities included in the equations of experimental sciences (physics, chemistry, etc.) involved in understanding the world empirical(i.e. experimentally) way.
Metrology penetrates into all sciences and disciplines dealing with measurements, and is a single science for them.
The basic concepts that metrology operates on are the following:
- physical quantity;
- unit of physical quantity;
- system of units of physical quantities;
- size of a unit of physical quantity (transfer of the size of a unit of physical quantity);
- means of measuring physical quantities;
- standard;
- exemplary measuring instrument;
- working measuring instrument;
- measurement of a physical quantity;
- measurement method;
- measurement result;
- measurement error;
- metrological service;
- metrological support, etc.
Let's define some basic concepts:
Physical quantity– a characteristic of one of the properties of a physical object (phenomenon or process), common in qualitative terms for many physical objects, but quantitatively individual for each object (i.e., the value of a physical quantity can be for one object a certain number of times more or less than for the other). For example: length, time, electric current.
Unit of physical quantity– a physical quantity of a fixed size, which is conventionally assigned a numerical value equal to 1, and used for the quantitative expression of homogeneous physical quantities. For example: 1 m is a unit of length, 1 s is a unit of time, 1A is a unit of electric current.
System of units of physical quantities– a set of basic and derived units of physical quantities, formed in accordance with accepted principles for a given system of physical quantities. For example: International System of Units (SI), adopted in 1960.
In the system of units of physical quantities there are basic units of the system of units(in SI – meter, kilogram, second, ampere, kelvin). From the combination of basic units are formed derived units(speed - m/s, density - kg/m3).
By adding installed prefixes to the basic units, multiple (for example, kilometer) or submultiple (for example, micrometer) units are formed.

Historically, the first system of units of physical quantities was the metric system of measures adopted in 1791 by the French National Assembly. It was not yet a system of units in the modern sense, but included units of length, area, volume, capacity and weight, which were based on two units: the meter and the kilogram.
In 1832, the German mathematician K. Gauss proposed a method for constructing a system of units as a set of basic and derivative ones. He constructed a system of units in which three arbitrary units independent of each other were taken as a basis - length, mass and time. All other units could be defined using these three. Gauss called such a system of units connected in a certain way with the three basic ones an absolute system. He took the millimeter, milligram and second as the basic units.
Subsequently, with the development of science and technology, a number of systems of units of physical quantities appeared, built on the principle proposed by Gauss, based on the metric system of measures, but differing from each other in basic units.
Let us consider the most important systems of units of physical quantities.
GHS system. The GHS system of units of physical quantities, in which the basic units are the centimeter as a unit of length, the gram as a unit of mass and the second as a unit of time, was established in 1881.
MKGSS system. The use of the kilogram as a unit of weight, and subsequently as a unit of force in general, led at the end of the 19th century to the formation of a system of units of physical quantities with three basic units: the meter - a unit of length, the kilogram-force - a unit of force and the second - a unit of time.
MCSA system. The foundations of this system were proposed in 1901 by the Italian scientist Giorgi. The basic units of the ISS system are the meter, kilogram, second and ampere.
The presence of a number of systems of units of physical quantities, as well as a significant number of non-system units, inconveniences associated with recalculation when moving from one system of units to another, required the unification of units of measurement. The growth of scientific, technical and economic ties between different countries necessitated such unification on an international scale.
A unified system of units of physical quantities was required, practically convenient and covering various areas of measurement. At the same time, it had to preserve the principle of coherence (equality to unity of the coefficient of proportionality in the equations of connection between physical quantities).
In 1954, the Tenth General Conference on Weights and Measures established six basic units (meter, kilogram, second, ampere, kelvin, candela + mole). The system, based on the six basic units approved in 1954, was called the International System of Units, abbreviated SI (SI - the initial letters of the French name Systeme International). A list of six basic, two additional and the first list of twenty-seven derivative units was approved, as well as prefixes for the formation of multiples and submultiples.
In the Russian Federation, the SI system is regulated by GOST 8.417-81.
Physical unit size– quantitative determination of a unit of physical quantity reproduced or stored by a measuring instrument. The size of the SI fundamental units is established by the definition of these units by the General Conference on Weights and Measures (GCPM). Thus, in accordance with the decision of the XIII CGPM, the unit of thermodynamic temperature, kelvin, is set equal to 1/273.16 of the thermodynamic temperature of the triple point of water.
Reproduction of units is carried out by national metrological laboratories using national standards. The difference between the size of the unit reproduced by the national standard and the size of the unit as defined by the CGPM is established during international comparisons of standards.
Unit size stored exemplary (OSI) or workers (RSI) measuring instruments, can be established in relation to the national primary standard. In this case, there may be several stages of comparison (through secondary standards and OSI).
Measurement of a physical quantity– a set of operations for the use of a technical means that stores a unit of physical quantity, consisting of comparison (explicitly or implicitly) of the measured quantity with its unit in order to obtain this quantity in the form most convenient for use.
Measuring principle– a physical phenomenon or effect underlying measurements using one or another type of measuring instrument.
Examples:
- application of the Doppler effect to measure speed;
- application of the Hall effect to measure magnetic field induction;
- use of gravity when measuring mass by weighing.

Types of measurements
By the nature of the dependence of the measured quantity on time measurements are divided into:
static, in which the measured quantity remains constant over time;
dynamic, during which the measured quantity changes and is not constant over time.
Static measurements are, for example, measurements of body dimensions, constant pressure, electrical quantities in circuits with a steady state, dynamic - measurements of pulsating pressures, vibrations, electrical quantities under conditions of a transient process.
By method of obtaining measurement results they are divided into:
straight;
indirect;
cumulative;
joint.
Direct- these are measurements in which the desired value of a physical quantity is found directly from experimental data. Direct measurements can be expressed by the formula , where is the desired value of the measured quantity, and is the value directly obtained from experimental data.
In direct measurements, the measured quantity is subjected to experimental operations, which is compared with the measure directly or using measuring instruments calibrated in the required units. Examples of straight lines are measuring body length with a ruler, mass using scales, etc.
Indirect- these are measurements in which the desired quantity is determined on the basis of a known relationship between this quantity and quantities subjected to direct measurements, i.e. They measure not the actual quantity being determined, but others that are functionally related to it. The value of the measured quantity is found by calculating using the formula , where is the functional dependence, which is known in advance, and is the value of the quantities measured directly.
Examples of indirect measurements: determining the volume of a body by direct measurements of its geometric dimensions, finding the electrical resistivity of a conductor by its resistance, length and cross-sectional area.
Indirect measurements are widely used in cases where the desired quantity is impossible or too difficult to measure directly, or when direct measurement gives a less accurate result. Their role is especially great when measuring quantities that are inaccessible to direct experimental comparison, for example, dimensions of the astronomical or subatomic order.
Aggregate- these are measurements of several quantities of the same name made simultaneously, in which the desired quantity is determined by solving a system of equations obtained by direct measurements of various combinations of these quantities.
An example of cumulative measurements is the determination of the mass of individual weights in a set (calibration using the known mass of one of them and the results of direct comparisons of the masses of various combinations of weights).
Joint- these are measurements of two or several quantities of different names made simultaneously to find dependencies between them.
An example is the measurement of electrical resistance at 200C and the temperature coefficients of a measuring resistor based on direct measurements of its resistance at different temperatures.

Measurement methods
Method of measurement is a method of experimentally determining the value of a physical quantity, i.e., a set of physical phenomena and measuring instruments used in measurements.


Direct assessment method consists in determining the value of a physical quantity using the reading device of a direct-acting measuring device. For example, measuring voltage with a voltmeter.
This method is the most common, but its accuracy depends on the accuracy of the measuring instrument.
Method of comparison with a measure - in this case, the measured value is compared with the value reproduced by the measure. The measurement accuracy may be higher than the accuracy of direct assessment.
There are the following types of comparison method with a measure:
Contrasting method, in which the measured and reproduced quantity simultaneously influence the comparison device, with the help of which the relationship between the quantities is established. Example: Measuring weight using a lever scale and a set of weights.
Differential method, in which the measuring device is affected by the difference between the measured value and the known value reproduced by the measure. In this case, the balancing of the measured value with a known one is not carried out completely. Example: Measuring DC voltage using a discrete voltage divider, a reference voltage source, and a voltmeter.
Null method, in which the resulting effect of the influence of both quantities on the comparison device is brought to zero, which is recorded by a highly sensitive device - a zero indicator. Example: Measuring the resistance of a resistor using a four-arm bridge, in which the voltage drop across a resistor of unknown resistance is balanced by the voltage drop across a resistor of known resistance.
Substitution method, in which the measured quantity and a known quantity are alternately connected to the input of the device, and the value of the measured quantity is estimated from two readings of the device, and then by selecting a known quantity, they are ensured that both readings coincide. With this method, high measurement accuracy can be achieved with a high precision measure of a known quantity and high sensitivity of the device. Example: accurate, precise measurement of a small voltage using a highly sensitive galvanometer, to which a source of unknown voltage is first connected and the deflection of the pointer is determined, and then using an adjustable source of known voltage, the same deflection of the pointer is achieved. In this case, the known voltage is equal to the unknown.
Match method, in which the difference between the measured value and the value reproduced by the measure is measured using the coincidence of scale marks or periodic signals. Example: measuring the rotation speed of a part using a flashing strobe lamp: observing the position of the mark on the rotating part at the moments of the lamp flashes, the speed of the part is determined from the known frequency of the flashes and the displacement of the mark.

Measuring instruments
Measuring instrument– a technical device (or a complex thereof) intended for measurements, having standardized metrological characteristics, reproducing and (or) storing a unit of physical quantity, the size of which is assumed to be constant within the established error and for a known time interval.
By metrological purposes measuring instruments are divided into:
- working measuring instruments, intended for measurements of physical quantities that are not related to the transfer of the unit size to other measuring instruments. RSIs are the most numerous and widely used. Examples of RSI: electric meter - for measuring electrical energy; theodolite - for measuring plane angles; bore gauge - for measuring small lengths (hole diameters); thermometer - for measuring temperature; measuring system of a thermal power plant, which receives measurement information about a number of physical quantities in different power units;
- exemplary measuring instruments, designed to ensure uniformity of measurements in the country.
By standardization- on the:
- standardized measuring instruments, manufactured in accordance with the requirements of state or industry standards.
- non-standardized measuring instruments– unique measuring instruments designed for a special measuring task, for which there is no need to standardize the requirements. Non-standardized measuring instruments are not subject to state tests (verifications), but are subject to metrological certification.
By degree of automation- on the:
- automatic measuring instruments that automatically perform all operations related to the processing of measurement results, their registration, data transfer or generation of a control signal;
- automated measuring instruments that perform one or part of the measuring operations automatically;
- non-automatic measuring instruments that do not have devices for automatically performing measurements and processing their results (tape measure, theodolite, etc.).
By design - on:
- measures;
- measuring transducers;
- measuring instruments;
- measuring installations;
- measuring and information systems;
Measure– a measuring instrument designed to reproduce a physical quantity of a given size. The measure acts as a carrier of a unit of physical quantity and serves as the basis for measurements. Examples of measures: normal element - measure of E.M.F. with a nominal voltage of 1V; A quartz resonator is a measure of the frequency of electrical oscillations.
Transducer– a measuring instrument for generating a signal of measuring information in a form convenient for transmission, further conversion, processing and (or) storage, but not amenable to direct observation by a person (operator). The term is often used primary measuring transducer or sensor. An electrical sensor is one or more measuring transducers combined into a single structure and used to convert a measured non-electrical quantity into an electrical one. For example: pressure sensor, temperature sensor, speed sensor, etc.
Measuring device– a measuring instrument designed to generate a measurement information signal in a form accessible to direct perception by a person (operator).
Measuring setup– a set of functionally integrated measuring instruments, designed to generate measurement information signals in a form convenient for direct observation by a person and located in one place. The measuring installation may include measures, measuring instruments and transducers, as well as various auxiliary devices.
Measuring and information system- a set of measuring instruments connected to each other by communication channels and designed to generate measurement information signals in a form convenient for automatic processing, transmission and (or) use in automatic control systems.

Metrological characteristics of measuring instruments
All measuring instruments, regardless of their specific design, have a number of common properties necessary for them to fulfill their functional purpose. Technical characteristics that describe these properties and influence the results and measurement errors are called metrological characteristics. A set of standardized metrological characteristics is established in such a way that with their help it is possible to estimate the error of measurements carried out under known operating conditions using individual measuring instruments or a set of measuring instruments, for example, automatic measuring systems.
One of the main metrological characteristics of measuring transducers is static conversion characteristic(otherwise called transformation function or calibration characteristic). It establishes the dependency of the informative parameter at output signal of the measuring transducer from the informative parameter X input signal.
The static characteristic is normalized by specifying it in the form of an equation, graph or table. The concept of static characteristics is also applicable to measuring instruments, if under the independent variable X understand the value of the measured quantity or informative parameter of the input signal, and by the dependent quantity y– instrument reading.
If the static characteristic of the transformation is linear, i.e. , then the coefficient TO called sensitivity of the measuring device (transducer). Otherwise, sensitivity should be understood as a derivative of the static characteristic.
An important characteristic of scale measuring instruments is value of division, i.e. that change in the measured value, which corresponds to moving the pointer by one scale division. If the sensitivity is constant at each point of the measurement range, then the scale is called uniform. At uneven scale the lowest scale division value of measuring instruments is standardized. Digital instruments do not have an explicit scale, and instead of the division price, the price of the unit of the least significant digit of the number in the instrument reading is indicated.
The most important metrological characteristic of measuring instruments is error.

Measurement errors
True value of a physical quantity– the value of a physical quantity that would ideally reflect the corresponding property of an object in quantitative and qualitative terms (according to 16263-70).
The result of any measurement differs from the true value of a physical quantity by a certain value, depending on the accuracy of the means and methods of measurement, the qualifications of the operator, the conditions under which the measurement was carried out, etc. The deviation of the measurement result from the true value of a physical quantity is called measurement error.
Since it is in principle impossible to determine the true value of a physical quantity, since this would require the use of an ideally accurate measuring instrument, in practice, instead of the concept of the true value of a physical quantity, the concept is used actual value of the measured quantity, which approximates the true value so closely that it can be used instead. This could be, for example, the result of measuring a physical quantity using an exemplary measuring instrument.
Absolute measurement error is the difference between the measurement result and the actual (true) value of a physical quantity:
D= hee - x
Relative measurement error is the ratio of the absolute error to the actual (true) value of the measured quantity (often expressed as a percentage):
d = (D/hee) 100%
Reduced error is the ratio of the absolute error to the standard value expressed as a percentage L– conventionally accepted value of a physical quantity, constant over the entire measurement range:
g = (D/ L) 100%
For instruments with a zero mark at the edge of the scale, the standard value is L equal to the final value of the measuring range. For instruments with a double-sided scale, i.e. with scale marks located on both sides of zero, the value L equal to the arithmetic sum of the modules of the final values ​​of the measurement range.
The measurement error (resulting error) is the sum of two components: systematic error And random error.
Systematic error– this is a component of the measurement error that remains constant or changes naturally with repeated measurements of the same quantity. The causes of systematic errors may be malfunctions of measuring instruments, imperfection of the measurement method, incorrect installation of measuring instruments, deviations from normal operating conditions, and characteristics of the operator himself. Systematic errors can, in principle, be identified and eliminated. This requires a thorough analysis of possible sources of error in each specific case.
Systematic errors are divided into methodological, instrumental And subjective.
Methodological errors arise from the imperfection of the measurement method, the use of simplifying assumptions and assumptions when deriving the formulas used, and the influence of the measuring device on the measured object. For example, measuring temperature using a thermocouple may contain a methodological error caused by a violation of the temperature regime of the measurement object due to the introduction of a thermocouple.
Instrumental errors depend on the errors of the measuring instruments used. Inaccuracy of calibration, design imperfections, changes in the characteristics of the device during operation, etc. are the reasons main errors measurement tool. Additional errors, associated with the deviation of the conditions in which the device operates from normal, are distinguished from instrumental ones (GOST 8.009-84), since they are related more to external conditions than to the device itself.
Subjective errors are caused by incorrect readings of the device by a person (operator). For example, an error from parallax caused by the wrong direction of view when observing the readings of a dial gauge. The use of digital instruments and automatic measurement methods eliminates this kind of error.
In many cases, the systematic error as a whole can be represented as the sum of two components additiveDA And multiplicative Dm.

This approach makes it possible to easily compensate for the influence of systematic error on the measurement result by introducing separate correction factors for each of these two components.
Random error is a component of the measurement error that changes randomly with repeated measurements of the same quantity. The presence of random errors is revealed during a series of measurements of a constant physical quantity, when it turns out that the measurement results do not coincide with each other. Often random errors arise due to the simultaneous action of many independent causes, each of which individually has little effect on the measurement result.
In many cases, the influence of random errors can be reduced by performing multiple measurements and then statistically processing the results.
In some cases, it turns out that the result of one measurement differs dramatically from the results of other measurements taken under the same controlled conditions. In this case they talk about gross error(measurement miss). The cause may be an operator error, the occurrence of a strong short-term interference, a shock, a violation of electrical contact, etc. Such a result, containing a gross error, must be identified, excluded and not taken into account in further statistical processing of measurement results.
Measuring instrument accuracy class– a generalized characteristic of a measuring instrument, determined by the limits of permissible basic and additional errors. The accuracy class is selected from the series (1; 1.5; 2; 2.5; 4; 5; 6)*10n, where n = 1; 0; -1; -2, etc. The accuracy class can be expressed as a single number or fraction (if the additive and multiplicative errors are comparable - for example, 0.2/0.05 - add./multi.).

Verification of measuring instruments

The basis for ensuring the uniformity of measuring instruments is the system for transmitting the size of the unit of the measured value. The technical form of supervision over the uniformity of measuring instruments is state (departmental) verification of measuring instruments, establishing their metrological serviceability.
Verification- determination by the metrological body of the errors of the measuring instrument and establishment of its suitability for use.
Those measuring instruments are considered suitable for use during a certain verification interval, the verification of which confirms their compliance with the metrological and technical requirements for this measuring instrument.
Measuring instruments are subjected to primary, periodic, extraordinary, inspection and expert verification.
Instruments undergo primary verification upon release from production or repair, as well as instruments received for import.
Instruments in operation or storage are subject to periodic verification at certain calibration intervals established to ensure the suitability of the instrument for use for the period between verifications.
Inspection verification is carried out to determine the suitability for use of measuring instruments in the implementation of state supervision and departmental metrological control over the condition and use of measuring instruments.
Expert verification is performed when controversial issues arise regarding metrological characteristics (MX), serviceability of measuring instruments and their suitability for use.
Reliable transfer of the size of units in all links of the metrological chain from standards or from the original standard measuring instrument to working measuring instruments is carried out in a certain order, given in verification schemes.
Verification diagram- this is a document approved in the prescribed manner that regulates the means, methods and accuracy of transferring the size of a unit of physical quantity from the state standard or the original standard measuring instrument to working means.
There are state, departmental and local verification schemes of state or departmental metrological services.
Instruments released from production and repair, received from abroad, as well as those in operation and storage are subject to verification. The basic requirements for the organization and procedure for verification of measuring instruments are established by GOST 8.513-84.

Fundamental documents to ensure the uniformity of measurements

GOST R 8.000-2000 GSI - Basic provisions
GOST 8.001-80 GSI - Organization and procedure for state testing of measuring instruments
GOST 8.002-86 GSI - State supervision and departmental control over measuring instruments
GOST 8.009-84 GSI - Standardized metrological characteristics of measuring instruments
GOST 8.050-73 GSI - Normal conditions for linear and angular measurements
GOST 8.051-81 GSI - Errors allowed when measuring linear dimensions up to 500 mm
GOST 8.057-80 GSI - Standards of units of physical quantities. Basic provisions
GOST 8.061-80 GSI - Verification diagrams. Content and structure
GOST 8.207-76 GSI - Direct constructions with multiple observations. Methods for processing observation results. Basic provisions
GOST 8.256-77 GSI - Standardization and determination of dynamic characteristics of analog measuring instruments. Basic provisions
GOST 8.310-90 GSI - State service of standard reference data. Basic provisions
GOST 8.372-80 GSI - Standards of units of physical quantities. Procedure for development, approval, registration, storage and application
GOST 8.315-97 GSI - Standard samples of the composition and properties of substances and materials. Basic provisions
GOST 8.381-80 GSI - Standards. Ways to Express Errors
GOST 8.383-80 GSI - State testing of measuring instruments. Basic provisions
GOST 8.395 GSI - Normal measurement conditions for verification. General requirements
GOST 8.401-80 GSI - Accuracy classes of measuring instruments. General requirements
GOST 8.417-81 GSI - Units of physical quantities
GOST 8.430-88 GSI - Designations of units of physical quantities for printing devices with a limited set of characters
GOST 8.508-84 GSI - Metrological characteristics of measuring instruments and accuracy characteristics of GSP automation equipment. General methods of assessment and control
GOST 8.513-84 GSI - Verification of measuring instruments. Organization and procedure
GOST 8.525-85 GSI - Installation of the highest accuracy for reproducing units of physical quantities. Procedure for development of certification, registration, storage and application
GOST 8.549-86 GSI - Errors allowed when measuring linear dimensions up to 50 mm with unspecified tolerances
GOST R 8.563-96 GSI - Measurement techniques
GOST 8.566-99 GSI - Interstate system of data on physical constants and properties of substances and materials. Basic provisions
GOST R 8.568-97 GSI - Certification of testing equipment. Basic provisions

Electrical measurements

Electromechanical measuring instruments

The block diagram of an analog electromechanical device in general can be represented as:


Measuring circuit – ensures the transformation of the electrical quantity X into an intermediate electrical quantity Y, functionally related to the value X and suitable for direct processing by the measuring mechanism.
The measuring mechanism is the main part of the device, designed to convert electromagnetic energy into mechanical energy necessary to create the angle of rotation a.

Reading device - consists of a pointer associated with a measuring mechanism and a scale.
According to the type of measuring mechanism, devices are divided into:
magnetoelectric mechanism;
magnetoelectric mechanism of ratiometric type;
electromagnetic mechanism;
electromagnetic mechanism of ratiometric type;
electromagnetic polarized mechanism;
electrodynamic mechanism;
electrodynamic mechanism of ratiometric type;
ferrodynamic mechanism;
ferrodynamic mechanism of ratiometric type;
electrostatic mechanism:
induction type measuring mechanism.

General technical requirements for all electrical measuring instruments are standardized by GOST 22261-82.
Symbols are defined in GOST 23217-78.

Magnetoelectric measuring instruments
The general structure of an electromagnetic type device is shown in the figure:

Figure a shows a diagram of a magnetoelectric mechanism with a moving magnet, and figure b shows a diagram of a fixed magnet.
The following designations are used in the figure:
arrow; 2- coil; 3- permanent magnet; 4- spring; 5- magnetic shunt; 6-pole lugs.
This mechanism, applied directly, can only measure direct currents.
Advantages of magnetoelectric devices: high torque at low currents, high accuracy classes, low self-consumption. Disadvantages of magnetoelectric devices: design complexity, high cost, low overload capacity.

Electrodynamic measuring instruments
The structure of the electrodynamic mechanism and the vector diagram explaining its operation are shown in the figure:


The electrodynamic measuring mechanism works on the principle of interaction of the magnetic fluxes of two coils. The electrodynamic mechanism consists of two coils. One of them is movable, and the other is fixed. The currents flowing through these coils and the magnetic fluxes generated by them during their interaction create a torque.
Electrodynamic system devices have low sensitivity and high self-consumption. They are mainly used at currents of 0.1...10A and voltages up to 300 V.

Ferrodynamic devices
Ferrodynamic devices are those in which the stationary coil of the electrodynamic mechanism is wound on a magnetic core. This protects against external electromagnetic fields and creates greater torque, i.e. increased sensitivity.

Electromagnetic measuring instruments
The design of an electromagnetic type measuring mechanism is shown in the figure:

In electromagnetic measuring mechanisms, the action of the magnetic field of a coil with current on a movable ferromagnetic (usually permolloy) petal is used to create torque. Advantages of electromagnetic mechanisms: suitability for operation in DC and AC circuits; high overload capacity; the ability to directly measure large currents and voltages; simplicity of design. Disadvantages of electromagnetic mechanisms: uneven scale; low sensitivity; high self-consumption of power; susceptibility to frequency changes; exposure to external magnetic fields and temperature.

Electrostatic measuring instruments
Diagrams of mechanisms of various designs are shown in the figure. Figure a shows a diagram with a changing area of ​​the electrodes, and figure b shows a diagram with a changing distance between the electrodes.


The operating principle of the electrostatic measuring mechanism is based on the interaction of forces arising between two differently charged plates. Advantages of electrostatic devices: high input resistance, low input capacitance, low self-consumption power, wide frequency range, can be used in AC and DC circuits, readings do not depend on the shape of the measured signal curve. Disadvantages of electrostatic devices: the devices have low sensitivity and low accuracy.

Induction measuring instruments
Electric energy meters are usually made based on an induction measuring mechanism. The device and vector diagram of the induction system device are shown in the figure:


The mechanism consists of two inductors made in the form of a rod and a U-shaped inductor, between which there is a movable non-ferromagnetic (aluminum) disk. Windings are wound on the inductors, through which currents I1 and I2 flow, respectively, exciting magnetic fluxes F1 and F2. A counting mechanism is connected to the axis of the disk, which counts the number of revolutions of the disk. To prevent idle rotation of the disk (to prevent self-propelling), a permanent magnet (brake magnet) is installed in the immediate vicinity of it.
If coil 1 is connected in parallel to the energy source, and coil 2 in series with the consumer, then we get a single-phase electric energy meter. The combination of two or three single-phase measuring mechanisms forms a three-phase meter. Advantages of induction system devices: high torque, low influence of external magnetic fields, high overload capacity. Disadvantages of induction system devices: low accuracy, high self-consumption, dependence of readings on frequency and temperature.

In recent years, electromechanical measuring instruments have been almost universally replaced by digital ones.

Electrical Signal Measurement

Voltage measurement

For this type of measurement, a circuit with an additional resistor is used.

It is carried out in the frequency range 0-109 Hz (at higher frequencies, voltage ceases to be an informative parameter). DC voltages from fractions of millivolts to hundreds of volts are often measured magnetoelectric voltmeters(accuracy class up to 0.05). The main disadvantage is the low input resistance, determined by the value of the additional resistance (tens of kOhms).
Free from this disadvantage electronic analog voltmeters. Their output impedance is tens of kOhms. They can measure resistance from units of µV to several kV. The main sources of errors here are: instability of elements and intrinsic noise of electronic circuits. The accuracy class of such devices is up to 1.5. Both magnetoelectric and electronic voltmeters are characterized by temperature errors, as well as mechanical errors in the measuring mechanism and scale errors.
Accurate DC voltage measurements are made using DC compensators(See the topic "Substitution method" in the "Measurement methods" section). The measurement accuracy reaches 0.0005%.
The root mean square (rms) value of alternating current is measured by electromagnetic (up to 1-2 kHz), electrodynamic (up to 2-3 kHz), ferrodynamic (up to 1-2 kHz), electrostatic (up to 10 MHz) and thermoelectric (up to 100 MHz) devices. The difference in the shape of the measured voltage from sinusoidal can sometimes lead to large errors.

The most convenient devices to use are digital voltmeters. They can measure both direct and alternating voltages. Accuracy class – up to 0.001, range – from units of microvolts to several kilovolts. Modern microprocessor CVs are equipped with a keyboard and often allow you to measure not only voltage, but also current, resistance, etc., i.e. they are multifunctional measuring instruments - testers (multimeters or avometers).

Current measurement
For this type of measurement, a shunt circuit is used.

Otherwise, everything said in relation to voltage measurements is also true for current measurements.

Electrical power measurement
It is carried out in DC and AC circuits using electrodynamic and ferrodynamic wattmeters. Changing the limits is achieved by switching sections of the current coil and connecting various additional resistors. Frequency range: from 0 to 2-3 kHz. Accuracy class: 0.1-0.5 for electrodynamic and 1.5–2.5 for ferromagnetic.
Power can also be measured indirectly, using an ammeter and voltmeter and then multiplying the results. The operation of digital wattmeters is based on the same principle.
There are modifications of wattmeters for measuring power in three-phase circuits.

Electrical Energy Measurement
It is carried out mainly by induction measuring instruments. In recent years, digital energy meters based on the principle of an ammeter-voltmeter with subsequent integration of the result of multiplication over time have become widespread.

Measuring parameters of electrical circuits

Measuring bridges
Single DC bridges are designed for measuring resistances of 10 ohms or more. The diagram of a single bridge is shown in the figure:

The diagonal indicated in the figure bd- is called the supply diagonal. It includes a power source (battery) G. Diagonal ac is called the measuring diagonal. It includes a balance indicator (galvanometer) R. Balance conditions for the bridge: . As a practical example, the parameters of the R-369 bridge are given. Range of measured resistances: 10-4…1.11111*1010 Ohm. The accuracy class in the range up to 10-3 Ohm is 1 and when measuring resistances from 1 to 103 Ohm the accuracy class is 0.005.
For accurate measurements of small resistances, double DC bridges are used. The double bridge diagram is shown in the figure:

During the measurement process, the measured resistance Rx is compared with the reference resistance R0. The resistance of the unknown resistor in the case of bridge equilibrium can be expressed as follows:
;
Double bridges allow you to measure resistance in the range of 10-8…1.11111*1010 Ohms.
AC bridges are used to measure both active and reactive resistances (capacitive and inductive). In this case, reactive elements - capacitance and inductance - can be used as bridge elements. Equilibrium equations are written by analogy with DC bridges.
In recent years, automatic bridges and compensators are often used to measure the parameters of electrical circuits, in which the process of balancing the bridge occurs automatically (using a reversible motor or electronic circuit). The use of automatic bridges in high-precision digital measuring devices is especially important.

Resistance measurement
Direct current resistance is measured both by direct assessment devices - ohmmeters and by bridges. Ohmmeters are most often made on the basis of a magnetoelectric mechanism. Measuring range of ohmmeters: from ten thousandths of an ohm to hundreds of megohms. The measurement error of ohmmeters is usually from 1 to several percent, but increases sharply at the edges of the scale. Digital multi-range ohmmeters, most often included in universal digital measuring instruments, have recently become widespread. The most accurate resistance can be measured using DC bridges.
Capacitance and inductance measurements

It is produced mainly using AC bridges with power frequencies of 100-1000 Hz. Most often, bridges for measuring resistance, capacitance and inductance are combined in one device - a universal measuring bridge. Such devices can measure inductance from fractions of microhenry to thousands of henry, capacitance - from hundredths of picofarads to thousands of microfarads. The error of universal bridges usually does not exceed hundredths of a percent.

Basics of standardization

State standardization system
The concept of standardization covers a wide area of ​​social activity, including scientific, technical, economic, economic, legal, aesthetic, and political aspects. In all countries, the development of the state economy, increased production efficiency, improved product quality, and increased living standards are associated with the widespread use of various forms and methods of standardization. Proper standardization promotes the development of specialization and cooperation in production.
Valid in Russia State Standardization System (GSS), uniting and streamlining work on standardization throughout the country, at all levels of production and management based on a set of state standards.
Standardization– establishment and application of rules in order to streamline activities with the participation of all interested parties. Standardization should ensure the fullest possible satisfaction of the interests of the manufacturer and consumer, increase labor productivity, economical consumption of materials, energy, working time and guarantee safety during production and operation.
The objects of standardization are products, norms, rules, requirements, methods, terms, designations, etc., which have the prospect of repeated use in science, technology, industry, agriculture, construction, transport and communications, culture, healthcare, and also in international trade.
Distinguish state (national) standardization And international standardization.
State standardization– a form of development and implementation of standardization, carried out under the leadership of state bodies according to unified state standardization plans.
International standardization carried out by special international organizations or a group of states with the aim of facilitating mutual trade, scientific, technical and cultural relations.
The standards established during standardization are formalized in the form of normative and technical documentation for standardization - standards and technical specifications.
Standard– a regulatory and technical document establishing a set of norms, rules, requirements for the object of standardization and approved by the competent authority. The standard can be developed both for items (products, raw materials, samples of substances), and for norms, rules, requirements for objects of an organizational, methodological and general technical nature of work, the procedure for developing documents, safety standards, quality management systems, etc.
Technical conditions (TU)– a regulatory and technical document on standardization, establishing a set of requirements for specific types, brands, and article numbers of products. Specifications are an integral part of the set of technical documentation for the products to which they apply.
Goals and objectives of standardization
the main objective State Standardization System (GSS)- with the help of standards that establish indicators, norms and requirements corresponding to the advanced level of domestic and foreign science, technology and production, to help ensure the proportional development of all sectors of the country’s national economy.
Other goals and objectives of standardization are:
1. Establishing requirements for the quality of finished products based on standardization of their quality characteristics, as well as the characteristics of raw materials, materials, semi-finished products and components;
2. Development and establishment of a unified system of product quality indicators, methods and means of control and testing, as well as the required level of product reliability, taking into account their purpose and operating conditions;
3. Establishment of standards, requirements and methods in the field of design and production in order to ensure optimal quality and eliminate the irrational variety of types, brands and standard sizes of products;
4. Development of unification of industrial products, increasing the level of interchangeability, efficiency of operation and repair of products;
5. Ensuring the unity and reliability of measurements, creating state standards of units of physical quantities;
6. Establishment of unified documentation systems;
7. Establishment of systems of standards in the field of occupational safety, environmental protection and improved use of natural resources.

Forms of standardization
Depending on the method of solving the main problem, several forms of standardization are distinguished.
Simplification– a form of standardization, which consists in simply reducing the number of brands of semi-finished products, components, etc. used in the development of a product or in its production. to a quantity that is technically and economically feasible, sufficient to produce products with the required quality indicators. Being the simplest form and the initial stage of more complex forms of standardization, simplification turns out to be economically beneficial, as it leads to simplification of production, facilitates logistics, warehousing, and reporting.
Unification– rational reduction in the number of types, types and sizes of objects of the same functional purpose. The objects of unification are most often individual products, their components, parts, components, grades of materials, etc. Unification is carried out based on the analysis and study of design options of products, their applicability by bringing together products and their components that are similar in purpose, design and size parts and components to a single standard (unified) design.
Currently, unification is the most common and effective form of standardization. The design of equipment, machines and mechanisms using standardized elements allows not only to reduce development time and reduce the cost of products, but also to increase their reliability, reduce the time for technological preparation and production development.
Typing is a type of standardization that consists in the development and establishment of standard solutions (design, technological, organizational, etc.) based on the most progressive methods and modes of operation. In relation to structures, typification consists in the fact that a certain design solution (existing or specially developed) is taken as the main one - the base for several identical or similar functional products. The required range and product options are built on the basis of the basic design by introducing a number of minor changes and additions to it.
Aggregation– a method of creating new machines, instruments and other equipment by assembling the final product from a limited set of standard and standardized components and assemblies that have geometric and functional interchangeability.

• International standard
• Regional standard
• Gosstandart of the Russian Federation (GOST R)
• Interstate standard (GOST)
• Industry standard
• Enterprise standard

Rules (PR) - a document establishing mandatory general technical provisions, procedures, methods of performing work (GOST R 1.0).
Recommendations (R) – a document containing voluntary general technical provisions, procedures, and methods of performing work.
Standard – a provision establishing quantitative or qualitative categories that must be satisfied (ISO\IEC2).
Regulation is a document containing mandatory legal norms and adopted by an authority.
Technical regulations are regulations that establish the characteristics of products (services) or related processes and production methods (GOST 1.0).

Unified state systems of standards
Based on comprehensive standardization, systems of standards have been developed in the Russian Federation, each of which covers a specific area of ​​activity carried out on a national scale or in certain sectors of the national economy.
Such systems include the State Standardization System (GSS), the Unified System of Design Documentation (ESKD), the Unified System of Technological Preparation of Production (ESTPP), the Unified System of Technological Documentation (ESTD), the Unified System of Classification and Coding of Technical and Economic Information, the State System for Ensuring Unity measurements (GSI), State System of Occupational Safety Standards (GSSBT), etc.
Let's look at some of them.
State Standardization System of the Russian Federation (GSS RF) began to take shape in 1992. Its basis is a fund of laws, regulations, and normative documents on standardization. The Fund presents a four-tier system:

• Technical legislation is the legal basis of the GSS.
• State standards, all-Russian classifiers of technical and economic information.
• Industry standards and standards of scientific, technical and engineering societies.
• Enterprise standards and technical conditions.

The legislative framework of the SSS is in its infancy.
Unified system of design documentation (ESKD). This system establishes for all organizations in the country the procedure for organizing design, uniform rules for the execution and execution of drawings and the management of drawing management, which simplifies design work, helps improve the quality and level of interchangeability of products and facilitates the reading and understanding of drawings in different organizations. ESKD includes more than 200 standards.
Unified System of Technological Documentation (USTD) is a set of state standards establishing:
forms of general-purpose documentation (route map of the technological process, summary specification, map of sketches, diagrams and adjustments, etc.);
rules for the design of technological processes and documentation forms for casting processes, cutting and cutting of workpieces, mechanical and heat treatment, welding, processes specific to the industries of radio engineering, electronics, etc.
There is a close connection between ESTD and ESKD. These systems play a big role in improving production management, increasing its efficiency, introducing automated control systems, etc.
State system for ensuring the uniformity of measurements (GSI) establishes general rules and standards for metrological support. The main objects of GSI standardization are:
units of physical quantities;
state standards and all-Union verification schemes;
methods and means of verification of measuring instruments;
nomenclature of standardized metrological characteristics of measuring instruments;
measurement accuracy standards;
methods of expression and forms of presentation of measurement results and measurement accuracy indicators;
measurement technique;
methodology for assessing the reliability and form of presentation of data on the properties of substances and materials;
requirements for standard samples of the composition and properties of substances and materials;
organization and procedure for conducting state tests, verification and metrological certification of measuring instruments, metrological examination of regulatory, technical, design, design and technological documentation, examination and certification of data on the properties of substances and materials;
terms and definitions in the field of metrology.

International standardization. ISO 9000 and ISO 14000 series standards
The most authoritative organization developing international standards is ISO (International Standard Organization).
The ISO 9000 and ISO 14000 series standards are a package of documents on quality assurance and environmental management. The ISO 9000 series of standards promote quality assurance in the design, development, production, installation and servicing of products, while ISO 14000 promotes environmental protection and pollution prevention while meeting the socio-economic needs of the enterprise itself.
The generality and universality of the ISO 9000 standards lies in the fact that the Quality Assurance models were not developed for any specific area - they are intended for use in all areas of industry and for all countries.
The development of a unified quality management system, both in regulated and non-regulated areas of product production by state legislation, helps to reduce the total number (and very significant) of various standards, regulations, regulations and other documents, often contradictory, that the manufacturer must comply with and comply with. which, due to their number and inconsistency, he is often unable to fulfill.

Standardization bodies and services of the Russian Federation
State management of standardization activities is carried out by the State Committee of the Russian Federation for Standardization and Metrology (Gosstandart of Russia). Work on standardization in the field of construction is organized by the State Committee for Construction, Architectural and Housing Policy of Russia (Gosstroy of Russia).

State metrological control and supervision

Functions of Gosstandart:

• Acting as a customer of state standards that establish fundamental and general technical requirements
• Review and adoption of state standards, as well as other regulatory documents of intersectoral importance
• Organization of work on the direct use of international, regional and national standards of foreign countries as State standards
• Ensuring the unity and reliability of measurements in the country, strengthening and developing the state metrological service
• Exercising state supervision over the implementation and compliance with mandatory requirements of state standards for the condition and use of measuring equipment
• Management of work to improve standardization, metrology and certification systems
• Participation in work on international cooperation in the field of standardization
• Publication and distribution of state standards and other regulatory documentation

Gosstandart carries out its functions through the bodies it created. The territorial bodies include standardization and metrology centers (CSM); There are more than 100 of them on the territory of the Russian Federation.
Enterprises create, if necessary, standardization services (department, laboratory, bureau), which carry out research and other work on standardization.

Certification Basics

Basic concepts of certification
The objects of certification include products, quality systems, enterprises, services, quality systems, personnel, workplaces, etc. The first, second and third parties participate in the certification of products, services and other objects.
The first side is the interests of suppliers.
The second side is the interests of buyers.
A third party is a person or bodies recognized as independent from the parties involved in the matter under consideration (ISO\IEC2). Certification can be mandatory or voluntary. The list of products subject to mandatory certification is approved by the Government of the Russian Federation.
Certification- this is a procedure for confirming conformity, through which an organization independent of the manufacturer (sellers, performer) and consumer (buyer) certifies in writing that the products meet the established requirements (RF Law of June 10, 1993 No. 5151-1 “On Certification of Products and Services” ).
Certification system- a set of certification participants who carry out certification according to the rules established in this system (rules for certification in the Russian Federation). The certification system is formed at the national (federal), regional and international levels. In our country, the certification system is created by specially authorized executive authorities according to Russian standards: GOSTR, the Ministry of Health of the Russian Federation, the State Committee of the Russian Federation for Communications and Informatization (GosKomSvyaz), etc. The Russian state standard certification system covers the area of ​​public consumption and services.
Certificate of conformity- this is a document issued according to the rules of the certification system to confirm compliance of certified products with established requirements (RF Law “On Certification of Products and Services”).
Declaration of Conformity- this is a document in which the manufacturer (seller-executor) certifies that the products supplied (sold) by him meet the established requirements. The list of products whose compliance can be confirmed by a declaration of conformity is established by a decree of the Government of the Russian Federation. The declaration of conformity has the same legal force as the certificate of conformity. In addition to the certificate of conformity and declaration of conformity, there is a mark of conformity.
Mark of conformity- this is a mark registered in the prescribed manner, which confirms the compliance of the products marked with it with the established requirements.

Main goals and principles of certification
Goals of certification.

• assistance to consumers in competent selection of products (services)
• consumer protection from dishonesty of the manufacturer (seller, performer)
• control of product (service, work) safety for a certain environment, life, health and property
• confirmation of product (service, work) quality indicators declared by the manufacturer (performer)
• creating conditions for the activities of organizations and entrepreneurs on the single commodity market of the Russian Federation, as well as for participation in international economic scientific and technical cooperation and international trade

Certification principles
1. The legislative basis for certification is the Russian Federation Law “Certification of Products and Services”, the Law “On the Protection of Consumer Rights” and other regulations.
2. Openness of the certification system (enterprises, institutions, etc., regardless of their form of ownership, participate in certification work).
3. Harmonization of rules and recommendations for certification with international norms and regulations.
4. Openness and closedness of information.
Openness - information of all its participants is available.
Confidentiality - confidentiality of information constituting a trade secret must be maintained.

Certification bodies
The certification body performs the following functions:

• Certifies products (services), issues certificates and licenses for the use of the mark of conformity
• Carries out inspection control over certified products (services)
• Suspends or revokes the validity of certificates issued by it
• Provides the applicant with the necessary information
• The OS is responsible for the validity and correctness of the issuance of the certificate of conformity and for compliance with the certification rules

Accredited testing laboratories (IL)- carry out tests of specific products or specific types of tests and issue test reports for certification purposes
IL is responsible for the compliance of the certification tests carried out by it with the requirements of the ND, as well as for the reliability and objectivity of the results. If the certification body is accredited as IL, then it is called a certification center (Russian Testing and Certification Center “Rostest-Moscow”).
Functions central body of certification systems (CAC) in the certification system of quality and production systems is carried out by the Technical Center of the Register of Quality Systems, operating within the structure of the State Standard of Russia. The functions of the DSP for voluntary certification are assigned to the All-Russian Scientific Research Institute of Certification.
Responsibilities of the DSP:

• Organization, coordination of work and establishment of procedural rules in the led certification system
• Consideration of appeals of applicants regarding the actions of OS, IL (centers

The specially authorized federal executive body in the field of certification in Russia is Gosstandart.

Procedure for product certification
Main stages:

• submitting an application for certification
• consideration and decision-making on the application
• selection, identification of samples and their testing
• production verification (if provided for by the certification scheme)
• analysis of the results obtained, making a decision on the possibility of issuing a certificate
• issuance of a certificate and license (permission) to use the mark of conformity
• inspection control of certified products in accordance with the certification scheme

Procedure for certification of products imported from abroad
Certificates or certificates of their recognition are submitted to the customs authorities along with certification by the cargo customs declaration and are necessary documents for obtaining permission to import products into Russia.
The list of products requiring confirmation of their safety when imported into the territory of the Russian Federation is established by Gosstandart upon approval of certification by the State Customs Committee (SCC). The State Customs Committee of Russia provides for the possibility of importing samples of goods for testing for certification purposes (for example, pre-contract).
Goods imported into Russia are subject to customs control confirming their safety by:

• conducting certification tests
• confirmation of foreign certificates

The territorial bodies of Gosstandart have the right to confirm a foreign certificate. There may be foreign certificates that do not require confirmation (agreement on mutual recognition of certification results).

Legislative framework for certification in the Russian Federation

Metrology - the science of measurements, methods and means of ensuring their unity and methods of achieving the required accuracy.

Metrology is of great importance for progress in the field of design, production, natural and technical sciences, since increasing the accuracy of measurements is one of the most effective ways for man to understand nature, discoveries and practical application of the achievements of the exact sciences.

Significant improvements in measurement accuracy have repeatedly been the main prerequisite for fundamental scientific discoveries.

Thus, an increase in the accuracy of measuring the density of water in 1932 led to the discovery of a heavy isotope of hydrogen - deuterium, which determined the rapid development of nuclear energy. Thanks to the ingenious understanding of the results of experimental studies on the interference of light, carried out with high accuracy and refuting the previously existing opinion about the mutual motion of the source and receiver of light, A. Einstein created his world-famous theory of relativity. The founder of world metrology D.I. Mendeleev said that science begins where they begin to measure. Metrology is of great importance for all industries, for solving problems of increasing production efficiency and product quality.

Let us give just a few examples characterizing the practical role of measurements for the country: the share of costs for measuring equipment is about 15% of all costs for equipment in mechanical engineering and approximately 25% in radio electronics; Every day in the country a significant number of different measurements are performed, amounting to billions; a significant number of specialists work in professions related to measurements.

The modern development of design ideas and technologies in all branches of production testifies to their organic connection with metrology. To ensure scientific and technological progress, metrology must be ahead of other areas of science and technology in its development, because for each of them, accurate measurements are one of the main ways to improve them.

Before considering various methods for ensuring uniformity of measurements, it is necessary to define basic concepts and categories. Therefore, in metrology it is very important to use terms correctly; it is necessary to determine what exactly is meant by a particular name.

The main tasks of metrology to ensure the uniformity of measurements and methods of achieving the required accuracies are directly related to the problems of interchangeability as one of the most important indicators of the quality of modern products. In most countries of the world, measures to ensure the uniformity and required accuracy of measurements are established by law, and in the Russian Federation in 1993 the law “On Ensuring the Uniformity of Measurements” was adopted.

Legal metrology sets the main task of developing a set of interrelated and interdependent general rules, requirements and norms, as well as other issues that require regulation and control by the state, aimed at ensuring the uniformity of measurements, progressive methods, methods and means of measurement and their accuracy.

In the Russian Federation, the basic requirements of legal metrology are summarized in the 8th grade State Standards.

Modern metrology includes three components:

1. Legislative.

2. Fundamental.

3. Practical.

Legal metrology– a section of metrology that includes sets of interrelated general rules, as well as other issues that require regulation and control by the state aimed at ensuring the uniformity of measurements and the uniformity of measuring instruments.

Issues of fundamental metrology (research metrology), the creation of systems of units of measurement, physical constants, the development of new measurement methods theoretical metrology.

Dealing with issues of practical metrology in various fields of activity as a result of theoretical research applied metrology.

Metrology tasks:

Ensuring uniformity of measurements

Determination of main directions, development of metrological support for production.

Organization and carrying out condition analysis and measurements.

Development and implementation of metrological support programs.

Development and strengthening of the metrological service.

Metrology objects: Measuring instruments, standards, measurement techniques, both physical and non-physical (production quantities).

History of the emergence and development of metrology.

Historically important stages in the development of metrology:

XVIII century- establishment standard meters(the standard is stored in France, in the Museum of Weights and Measures; is now more of a historical artifact than a scientific instrument);

1832 year - creation Carl Gauss absolute systems of units;

1875 year - signing of international Metric Convention;

1960 year - development and installation International System of Units (SI);

XX century- metrological studies of individual countries are coordinated by International Metrological Organizations.

Great Russian history of metrology:

accession to the Meter Convention;

1893 year - creation D. I. Mendeleev Main Chamber of Weights and Measures(modern name: "Research Institute of Metrology named after. Mendeleev").

Metrology as a science and field of practical activity arose in ancient times. The basis of the system of measures in ancient Russian practice was the ancient Egyptian units of measurement, and they, in turn, were borrowed from ancient Greece and Rome. Naturally, each system of measures was distinguished by its own characteristics, associated not only with the era, but also with the national mentality.

The names of the units and their sizes corresponded to the possibility of making measurements using “improvised” methods, without resorting to special devices. Thus, in Rus' the main units of length were the span and the cubit, and the span served as the main ancient Russian measure of length and meant the distance between the ends of the thumb and index finger of an adult. Later, when another unit appeared - the arshin - the span (1/4 arshin) gradually fell out of use.

The cubit measure came to us from Babylon and meant the distance from the bend of the elbow to the end of the middle finger of the hand (sometimes a clenched fist or thumb).

Since the 18th century In Russia, the inch, borrowed from England (called “finger”), as well as the English foot, began to be used. A special Russian measure was the sazhen, equal to three cubits (about 152 cm) and the oblique sazhen (about 248 cm).

By decree of Peter I, Russian measures of length were coordinated with English ones, and this is essentially the first step in the harmonization of Russian metrology with European ones.

The metric system of measures was introduced in France in 1840. The great importance of its adoption in Russia was emphasized by D.I. Mendeleev, predicting the great role of the universal spread of the metric system as a means of promoting the “future desired rapprochement of peoples.”

With the development of science and technology, new measurements and new units of measurement were required, which in turn stimulated the improvement of fundamental and applied metrology.

Initially, the prototype of units of measurement was sought in nature, studying macro-objects and their movement. Thus, a second began to be considered part of the period of revolution of the Earth around its axis. Gradually, the search moved to the atomic and intra-atomic level. As a result, the “old” units (measures) were refined and new ones appeared. So, in 1983, a new definition of the meter was adopted: this is the length of the path traveled by light in a vacuum in 1/299792458 of a second. This became possible after the speed of light in a vacuum (299,792,458 m/s) was accepted by metrologists as a physical constant. It is interesting to note that from the point of view of metrological rules, the meter now depends on the second.

In 1988, new constants in the field of measuring electrical units and quantities were adopted at the international level, and in 1989, the new International Practical Temperature Scale ITS-90 was adopted.

These few examples show that metrology as a science is developing dynamically, which naturally contributes to the improvement of measurement practices in all other scientific and applied fields.

The rapid development of science, technology and technology in the twentieth century required the development of metrology as a science. In the USSR, metrology developed as a state discipline, because The need to improve the accuracy and reproducibility of measurements grew with industrialization and the growth of the military-industrial complex. Foreign metrology was also based on practical requirements, but these requirements came mainly from private firms. An indirect consequence of this approach was state regulation of various concepts related to metrology, that is GOSTing everything that needs to be standardized. Abroad, this task has been taken on by non-governmental organizations, for example ASTM. Due to this difference in metrology of the USSR and post-Soviet republics, state standards (standards) are recognized as dominant, in contrast to the competitive Western environment, where a private company may not use a poorly proven standard or instrument and agree with its partners on another option for certifying the reproducibility of measurements.

Metrology objects.

Measurements, as the main object of metrology, are associated both with physical quantities and with quantities related to other sciences (mathematics, psychology, medicine, social sciences, etc.). Next we will consider concepts related to physical quantities.

Physical quantity . This definition means a property that is qualitatively common to many objects, but quantitatively individual for each object. Or, following Leonhard Euler, “a quantity is anything that can increase or decrease, or something to which something can be added or from which something can be taken away.”

In general, the concept of “quantity” is multi-specific, i.e., it relates not only to physical quantities that are objects of measurement. Quantities can include the amount of money, ideas, etc., since the definition of quantity is applicable to these categories. For this reason, the standards (GOST-3951-47 and GOST-16263-70) provide only the concept of a “physical quantity,” i.e., a quantity that characterizes the properties of physical objects. In measurement technology, the adjective “physical” is usually omitted.

Unit of physical quantity - a physical quantity that, by definition, is given a value equal to one. Referring once again to Leonhard Euler: “It is impossible to define or measure one quantity except by taking as known another quantity of the same kind and indicating the ratio in which it stands to it.” In other words, in order to characterize any physical quantity, one must arbitrarily choose as a unit of measurement some other quantity of the same kind.

Measure - a carrier of the size of a unit of physical quantity, i.e. a measuring instrument designed to reproduce a physical quantity of a given size. Typical examples of measures are weights, tape measures, and rulers. In other types of measurements, measures can take the form of a prism, a substance with known properties, etc. When considering individual types of measurements, we will specifically dwell on the problem of creating measures.

The concept of a system of units. Non-systemic units. Natural systems of units.

System of units - a set of basic and derived units related to a certain system of quantities and formed in accordance with accepted principles. The system of units is built on the basis of physical theories that reflect the interrelationship of physical quantities existing in nature. When determining the units of a system, a sequence of physical relationships is selected in which each subsequent expression contains only one new physical quantity. This makes it possible to determine a unit of physical quantity through a set of previously defined units, and ultimately through the basic (independent) units of the system (see. Units of physical quantities).

In the first Systems of Units, units of length and mass were chosen as the main ones, for example, in Great Britain, the foot and the English pound, in Russia - the arshin and the Russian pound. These systems included multiple and submultiple units that had their own names (yard and inch - in the first system, fathom, vershok, foot and others - in the second), due to which a complex set of derived units was formed. Inconveniences in the field of trade and industrial production associated with differences in national systems of units prompted the idea of ​​developing the metric system of measures (18th century, France), which served as the basis for the international unification of units of length (meter) and mass (kilogram), as well as the most important derived units (area, volume, density).

In the 19th century, K. Gauss and V.E. Weber proposed a system of units for electrical and magnetic quantities, called absolute by Gauss.

In it, the millimeter, milligram and second were taken as the basic units, and derivative units were formed according to the equations of connection between quantities in their simplest form, that is, with numerical coefficients equal to one (such systems were later called coherent). In the 2nd half of the 19th century, the British Association for the Advancement of Science adopted two systems of units: SGSE (electrostatic) and SGSM (electromagnetic). This laid the foundation for the formation of other Systems of units, in particular the symmetrical system of the SGS (which is also called the Gauss system), the technical system (m, kgf, sec; see. MKGSS system of units),MTS system units and others. In 1901, the Italian physicist G. Giorgi proposed a system of units based on the meter, kilogram, second and one electrical unit (later the ampere was chosen; see MKSA system of units). The system included units that became widespread in practice: ampere, volt, ohm, watt, joule, farad, henry. This idea was the basis for the 11th General Conference on Weights and Measures adopted in 1960 International System of Units (SI). The system has seven basic units: meter, kilogram, second, ampere, kelvin, mole, candela. The creation of the SI opened up the prospect of a universal unification of units and resulted in many countries deciding to transition to this system or to use it preferentially.

Along with practical systems of units, physics uses systems based on universal physical constants, for example, the speed of light in a vacuum, the charge of an electron, Planck’s constant and others.

Non-system units , units of physical quantities that are not included in any system of units. Extra-system units were chosen in separate areas of measurement without connection with the construction of systems of units. Extra-system units can be divided into independent (defined without the help of other units) and arbitrarily selected, but defined through other units. The first include, for example, a degree Celsius, defined as 0.01 of the gap between the boiling point of water and the melting point of ice at normal atmospheric pressure, a full angle (revolution), and others. The second includes, for example, a power unit - horsepower (735.499 W), pressure units - technical atmosphere (1 kgf / cm 2), millimeter of mercury (133.322 N / m 2), bar (10 5 N / m 2) and other. In principle, the use of non-systemic units is undesirable, since inevitable recalculations require time and increase the likelihood of errors.

Natural systems of units , systems of units in which fundamental physical constants are taken as the basic units - such as, for example, the gravitational constant G, the speed of light in vacuum c, Planck's constant h, Boltzmann's constant k, Avogadro's number N A, electron charge e, electron rest mass m e and other. The size of the basic units in Natural Systems of Units is determined by natural phenomena; This makes natural systems fundamentally different from other systems of units, in which the choice of units is determined by the requirements of measurement practice. According to the idea of ​​M. Planck, who first (1906) proposed the Natural Systems of Units with the basic units h, c, G, k, it would be independent of earthly conditions and suitable for any time and place in the Universe.

A number of other Natural systems of units have been proposed (G. Lewis, D. Hartree, A. Ruark, P. Dirac, A. Gresky, etc.). Natural systems of units are characterized by extremely small sizes of units of length, mass and time (for example, in the Planck system - 4.03 * 10 -35 m, 5.42 * 10 -8 kg and 1.34 * 10 -43 sec, respectively) and , on the contrary, the enormous dimensions of the temperature unit (3.63 * 10 32 C). As a result, Natural systems of units are inconvenient for practical measurements; in addition, the accuracy of reproduction of units is several orders of magnitude lower than that of the basic units of the International System (SI), since it is limited by the accuracy of knowledge of physical constants. However, in theoretical physics, the use of Natural Systems of Units sometimes allows one to simplify equations and provides some other advantages (for example, the Hartree system allows one to simplify the writing of quantum mechanics equations).

Units of physical quantities.

Units of physical quantities - specific physical quantities, which by definition are assigned numerical values ​​equal to 1. Many units of physical quantities are reproduced by measures used for measurements (for example, meter, kilogram). In the early stages of the development of material culture (in slave and feudal societies), there were units for a small range of physical quantities - length, mass, time, area, volume. Units of physical quantities were chosen independently of each other, and, moreover, were different in different countries and geographical areas. This is how a large number of often identical in name, but different in size units arose - elbows, feet, pounds. As trade relations between peoples expanded and science and technology developed, the number of units of physical quantities increased and the need for unification of units and the creation of systems of units was increasingly felt. Special international agreements began to be concluded on Units of physical quantities and their systems. In the 18th century, the metric system of measures was proposed in France, which later received international recognition. On its basis, a number of metric systems of units were built. Currently, there is further streamlining of Units of physical quantities based on International System of Units(SI).

Units of physical quantities are divided into system ones, that is, those included in any system of units, and non-systemic units (e.g. mmHg, horsepower, electron volts). System units of physical quantities are divided into basic ones, chosen arbitrarily (meter, kilogram, second, etc.), and derivatives, formed according to equations of connection between quantities (meter per second, kilogram per cubic meter, newton, joule, watt, etc. ). For the convenience of expressing quantities many times larger or smaller than Units of physical quantities, multiple units and submultiples are used. In metric systems of units, multiples and submultiples Units of physical quantities (except for units of time and angle) are formed by multiplying the system unit by 10 n, where n is a positive or negative integer. Each of these numbers corresponds to one of the decimal prefixes adopted to form multiples and submultiples.

International system of units.

International system of units (Systeme International d'Unitees), a system of units of physical quantities adopted by the 11th General Conference on Weights and Measures (1960). The abbreviation of the system is SI (in Russian transcription - SI). The International System of Units was developed to replace a complex set of systems units and individual non-systemic units, developed on the basis of the metric system of measures, and simplification of the use of units.The advantages of the International System of Units are its universality (covers all branches of science and technology) and coherence, i.e. the consistency of derivative units that are formed according to equations, not containing coefficients of proportionality. Thanks to this, when calculating, if you express the values ​​of all quantities in units of the International System of Units, there is no need to enter coefficients into the formulas that depend on the choice of units.

The table below shows the names and designations (international and Russian) of the main, additional and some derivative units of the International System of Units. Russian designations are given in accordance with current GOSTs; The designations provided for by the draft new GOST "Units of Physical Quantities" are also given. The definition of basic and additional units and quantities, the relationship between them is given in articles about these units.

The first three basic units (meter, kilogram, second) allow the formation of coherent derivative units for all quantities of a mechanical nature, the rest are added to form derivative units of quantities that are not reducible to mechanical: ampere - for electrical and magnetic quantities, kelvin - for thermal, candela - for light and mole - for quantities in the field of physical chemistry and molecular physics. The additional units of radians and steradians are used to form derived units of quantities that depend on plane or solid angles. To form the names of decimal multiples and submultiples, special SI prefixes are used: deci (to form units equal to 10 -1 relative to the original), centi (10 -2), milli (10 -3), micro (10 -6), nano (10 -9), pico (10 -12), femto (10 -15), atto (10 -18), deca (10 1), hecto (10 2), kilo (10 3), mega (10 6 ), giga (10 9), tera (10 12).

Unit systems: MKGSS, ISS, MCSA, MKSK, MTS, SGS.

MKGSS system of units (MkGS system), a system of units of physical quantities, the main units of which are: meter, kilogram-force, second. It came into practice at the end of the 19th century and was approved in the USSR by OST VKS 6052 (1933), GOST 7664-55 and GOST 7664-61 “Mechanical Units”. The choice of the force unit as one of the basic units led to the widespread use of a number of units of the MKGSS system of units (mainly units of force, pressure, mechanical stress) in mechanics and technology. This system is often called the technical system of units. The unit of mass in the MKGSS system of units is the mass of a body acquiring an acceleration of 1 m/sec 2 under the influence of a force of 1 kgf applied to it. This unit is sometimes called the technical unit of mass (i.e.) or inertia. 1 i.e. = 9.81 kg. The MKGSS system of units has a number of significant disadvantages: inconsistency between mechanical and practical electrical units, the absence of a kilogram-force standard, the rejection of the common unit of mass - the kilogram (kg) and, as a consequence (in order not to use i.e.) - the formation of quantities with involving weight instead of mass (specific gravity, weight consumption, etc.), which sometimes led to confusion between the concepts of mass and weight, the use of the designation kg instead of kgf, etc. These shortcomings led to the adoption of international recommendations on the abandonment of the IKGSS system of units and the transition to International System of Units(SI).

ISS system of units (MKS system), a system of units of mechanical quantities, the main units of which are: meter, kilogram (unit of mass), second. It was introduced into the USSR by GOST 7664-55 "Mechanical units", replaced by GOST 7664-61. It is also used in acoustics in accordance with GOST 8849-58 "Acoustic units". The ISS system of units is included as part of International system of units(SI).

MKSA system of units (MKSA system), a system of units of electrical and magnetic quantities, the main units of which are: meter, kilogram (unit of mass), second, ampere. The principles for constructing ISS systems of units were proposed in 1901 by the Italian scientist G. Giorgi, therefore the system has a second name - Giorgi system of units. The MKSA system of units is used in most countries of the world; in the USSR it was established by GOST 8033-56 “Electrical and magnetic units”. All previously widespread practical electrical units belong to the MCSA system of units: ampere, volt, ohm, coulomb, etc.; The MKSA system of units is included as an integral part in International system of units(SI).

MKSK system of units (MKSK system), system of units of thermal quantities, basic. The units of which are: meter, kilogram (unit of mass), second, Kelvin (unit of thermodynamic temperature). The use of the MKSK system of units in the USSR is established by GOST 8550-61 “Thermal Units” (this standard still uses the previous name of the unit of thermodynamic temperature - “degree Kelvin”, changed to “Kelvin” in 1967 by the 13th General Conference on Weights and Measures). In the IKSK system of units, two temperature scales are used: the thermodynamic temperature scale and the International Practical Temperature Scale (MPTS-68). Along with Kelvin, the degree Celsius, denoted °C and equal to kelvin (K), is used to express thermodynamic temperature and temperature difference. As a rule, the Kelvin temperature T is given below 0 °C, and the Celsius temperature t is above 0 °C (t = T-To, where To = 273.15 K). MPTS-68 also distinguishes between the international practical temperature Kelvin (symbol T 68) and the international practical temperature Celsius (t 68); they are related by the relation t 68 = T 68 - 273.15 K. The units of T 68 and t 68 are Kelvin and degrees Celsius, respectively. The names of derived heat units can include both Kelvin and degrees Celsius. The MKSK system of units is included as an integral part in International system of units(SI).

MTS system of units (MTS system), a system of units of physical quantities, the main units of which are: meter, ton (unit of mass), second. It was introduced in France in 1919, in the USSR - in 1933 (canceled in 1955 due to the introduction of GOST 7664-55 "Mechanical units"). The MTC system of units was constructed similarly to that used in physics GHS system of units and was intended for practical measurements; For this purpose, larger units of length and mass were chosen. The most important derived units: force - sten (sn), pressure - piezo (pz), work - sten-meter, or kilojoule (kJ), power - kilowatt (kW).

GHS system of units , system of units of physical quantities. in which three basic units are adopted: length - centimeter, mass - gram and time - second. A system with basic units of length, mass and time was proposed by the Committee on Electrical Standards of the British Association for the Advancement of Science, formed in 1861, which included outstanding physicists of the time (W. Thomson (Kelvin), J. Maxwell, C. Wheatstone, etc. .), as a system of units covering mechanics and electrodynamics. After 10 years, the association formed a new committee, which finally chose the centimeter, gram and second as the main units. The First International Congress of Electricians (Paris, 1881) also adopted the GHS system of units, and since then it has been widely used in scientific research. With the introduction of the International System of Units (SI) in scientific works on physics and astronomy, along with SI units, it is allowed to use CGS units of the system of units.

The most important derived units of the GHS system of units in the field of mechanical measurements include: unit of speed - cm/sec, acceleration - cm/sec 2, force - dyne (dyne), pressure - dyne/cm 2, work and energy - erg, power - erg /sec, dynamic viscosity - poise (pz), kinematic viscosity - stokes (st).

For electrodynamics, two SGS system of units were initially adopted: electromagnetic (SGSM) and electrostatic (SGSE). The construction of these systems was based on Coulomb's law - for magnetic charges (SGSM) and electric charges (SGSE). Since the 2nd half of the 20th century, the so-called symmetrical GHS system of units has become most widespread (it is also called a mixed or Gaussian system of units).

Legal basis for ensuring the uniformity of measurements.

Metrological services of state governing bodies and legal entities organize their activities based on the provisions of the Laws “On Ensuring the Uniformity of Measurements”, “On Technical Regulation” (formerly “On Standardization”, “On Certification of Products and Services”), as well as decrees of the Government of the Russian Federation, administrative acts of the constituent entities of the federation, regions and cities, regulatory documents of the State System for Ensuring the Uniformity of Measurements and regulations of the State Standard of the Russian Federation.

In accordance with current legislation, the main tasks of metrological services include ensuring the uniformity and required accuracy of measurements, increasing the level of metrological support for production, and implementing metrological control and supervision using the following methods:

calibration of measuring instruments;

supervision over the condition and use of measuring instruments, certified measurement techniques, standards of units of quantities used for calibration of measuring instruments, compliance with metrological rules and regulations;

issuing mandatory instructions aimed at preventing, stopping or eliminating violations of metrological rules and regulations;

checking the timeliness of submission of measuring instruments for testing in order to approve the type of measuring instruments, as well as for verification and calibration. In Russia, the Standard Regulations on Metrological Services have been adopted. This Regulation determines that the metrological service of a state governing body is a system formed by order of the head of the state governing body, which may include:

structural units (service) of the chief metrologist in the central office of the state governing body;

head and base organizations of the metrological service in industries and sub-sectors, appointed by the state governing body;

metrological services of enterprises, associations, organizations and institutions.

12/27/2002 a fundamentally new strategic Federal Law “On Technical Regulation” was adopted, which regulates relations arising in the development, adoption, application and implementation of mandatory and voluntary requirements for products, production processes, operation, storage, transportation, sales, disposal, performance of work and provision of services, as well as in assessing conformity (technical regulations and standards must ensure the practical implementation of legislative acts).

The introduction of the Law “On Technical Regulation” is aimed at reforming the system of technical regulation, standardization and quality assurance and is caused by the development of market relations in society.

Technical regulation is the legal regulation of relations in the field of establishing, applying and using mandatory requirements for products, production processes, operation, storage, transportation, sales and disposal, as well as in the field of establishing and applying on a voluntary basis requirements for products, production processes, operation, storage, transportation, sale and disposal, performance of work and provision of services and legal regulation of relations in the field of conformity assessment.

Technical regulation must be carried out in accordance with principles:

application of uniform rules for establishing requirements for products, production processes, operation, storage, transportation, sales and disposal, performance of work and provision of services;

compliance of technical regulation with the level of development of the national economy, development of the material and technical base, as well as the level of scientific and technical development;

independence of accreditation bodies, certification bodies from manufacturers, sellers, performers and purchasers;

unified system and rules of accreditation;

unity of rules and methods of research, testing and measurements when carrying out mandatory conformity assessment procedures;

uniformity of application of the requirements of technical regulations, regardless of the characteristics and types of transactions;

inadmissibility of restricting competition in the implementation of accreditation and certification;

the inadmissibility of combining the powers of state control (supervision) bodies and certification bodies;

the inadmissibility of combining accreditation and certification powers by one body;

inadmissibility of extra-budgetary financing of state control (supervision) over compliance with technical regulations.

One of main ideas of the law thing is:

mandatory requirements contained today in regulations, including state standards, are included in the field of technical legislation - in federal laws (technical regulations);

a two-level structure of regulatory and legal documents is being created: technical regulations(contains mandatory requirements) and standards(contain voluntary norms and rules harmonized with technical regulations).

The developed program for reforming the standardization system in the Russian Federation was designed for 7 years (until 2010), during which time it was necessary:

develop 450-600 technical regulations;

extract mandatory requirements from the relevant standards;

review sanitary rules and regulations (SanPin);

review the building codes and regulations (SNiP), which are essentially technical regulations.

The significance of the introduction of the Federal Law “On Technical Regulation”:

the introduction of the RF Law “On Technical Regulation” fully reflects what is happening today in the world of economic development;

it aims to remove technical barriers to trade;

The law creates conditions for Russia's accession to the World Trade Organization (WTO).

Concept and classification of measurements. Main measurement characteristics.

Measurement - a cognitive process consisting of comparing a given value with a known value taken as a unit. Measurements are divided into direct, indirect, cumulative and joint.

Direct measurements - a process in which the desired value of a quantity is found directly from experimental data. The simplest cases of direct measurements are measuring length with a ruler, temperature with a thermometer, voltage with a voltmeter, etc.

Indirect measurements - type of measurement, the result of which is determined from direct measurements associated with the measured value by a known dependence. For example, area can be measured as the product of the results of two linear coordinate measurements, volume - as the product of three linear measurements. Also, the resistance of an electrical circuit or the power of an electrical circuit can be measured by the values ​​of potential difference and current.

Aggregate Measurements - these are measurements in which the result is found from data from repeated measurements of one or more quantities of the same name for various combinations of measures or these quantities. For example, cumulative measurements are those in which the mass of the individual weights of a set is found from the known mass of one of them and from the results of direct comparisons of the masses of various combinations of weights.

Joint measurements They call the direct or indirect measurements of two or more different quantities. The purpose of such measurements is to establish a functional relationship between quantities. For example, measurements of temperature, pressure and volume occupied by gas, measurements of body length depending on temperature, etc. will be joint.

According to the conditions that determine the accuracy of the result, measurements are divided into three classes:

measuring the highest possible accuracy achievable with the existing level of technology;

control and verification measurements performed with specified accuracy;

technical measurements, the error of which is determined by the metrological characteristics of measuring instruments.

Technical measurements define the class of measurements performed in production and operational conditions, when the accuracy of the measurement is determined directly by the measuring instruments.

Unity of measurements- a state of measurements in which their results are expressed in legal units and the errors are known with a given probability. The uniformity of measurements is necessary in order to be able to compare the results of measurements taken at different times, using different methods and means of measurement, as well as in different geographical locations.

The uniformity of measurements is ensured by their properties: convergence of measurement results; reproducibility of measurement results; correctness of measurement results.

Convergence- this is the proximity of measurement results obtained by the same method, identical measuring instruments, and the proximity to zero of the random measurement error.

Reproducibility of measurement results characterized by the closeness of measurement results obtained by different measuring instruments (of course the same accuracy) by different methods.

Accuracy of measurement results is determined by the correctness of both the measurement techniques themselves and the correctness of their use in the measurement process, as well as the closeness to zero of the systematic measurement error.

Accuracy of measurements characterizes the quality of measurements, reflecting the closeness of their results to the true value of the measured value, i.e. close to zero measurement error.

The process of solving any measurement problem usually includes three stages:

preparation,

carrying out a measurement (experiment);

processing of results. In the process of carrying out the measurement itself, the measurement object and the measuring instrument are brought into interaction. Measuring instrument - a technical tool used in measurements and having standardized metrological characteristics. The measuring instruments include measures, measuring instruments, measuring installations, measuring systems and converters, standard samples of the composition and properties of various substances and materials. According to time characteristics, measurements are divided into:

static, in which the measured value remains unchanged over time;

dynamic, during which the measured value changes.

According to the method of expressing the results of measurements, they are divided into:

absolute, which are based on direct or indirect measurements of several quantities and on the use of constants, and as a result of which the absolute value of the quantity is obtained in the corresponding units;

relative measurements, which do not allow you to directly express the result in legal units, but allow you to find the ratio of the measurement result to any value of the same name with an unknown value in some cases. For example, this could be relative humidity, relative pressure, elongation, etc.

The main characteristics of measurements are: measurement principle, measurement method, error, accuracy, reliability and correctness of measurements.

Measuring principle - a physical phenomenon or a combination of them that forms the basis of measurements. For example, mass can be measured based on gravity, or it can be measured based on inertial properties. Temperature can be measured by the thermal radiation of the body or by its effect on the volume of some liquid in a thermometer, etc.

Measurement method - a set of principles and measuring instruments. In the example mentioned above with measuring temperature, measurements by thermal radiation are classified as a non-contact method of thermometry; measurements with a thermometer are a contact method of thermometry.

Measurement error - the difference between the value of a quantity obtained during measurement and its true value. Measurement error is associated with imperfection of measurement methods and instruments, insufficient experience of the observer, and extraneous influences on the measurement result. The causes of errors and ways to eliminate or minimize them are discussed in detail in a special chapter, since the assessment and accounting of measurement errors is one of the most important sections of metrology.

Accuracy of measurements - measurement characteristic, reflecting the closeness of their results to the true value of the measured value. Quantitatively, the accuracy is expressed by the reciprocal of the modulus of the relative error, i.e.

where Q is the true value of the measured quantity, D is the measurement error equal to

(2)

where X is the measurement result. If, for example, the relative measurement error is 10 -2%, then the accuracy will be 10 4.

Accuracy of measurements is the quality of measurements, reflecting the closeness to zero of systematic errors, i.e. errors that remain constant or change naturally during the measurement process. The accuracy of measurements depends on how correctly (correctly) the methods and measuring instruments were chosen.

Reliability of measurements - a characteristic of the quality of measurements that divides all results into reliable and unreliable, depending on whether the probabilistic characteristics of their deviations from the true values ​​of the corresponding quantities are known or unknown. Measurement results whose reliability is unknown can serve as a source of misinformation.

Measuring instruments.

Measuring instrument (MI) – a technical device intended for measurements, having standardized metrological characteristics, reproducing or storing a unit of physical quantity, the size of which is assumed to be unchanged over a known time interval.

The above definition expresses the essence of a measuring instrument, which, firstly, stores or reproduces the unit, secondly, this unit unchangeable. These most important factors determine the possibility of carrying out measurements, i.e. make a technical device a means of measurement. This is how measuring instruments differ from other technical devices.

Measuring instruments include measuring measures: converters, instruments, installations and systems.

Measure of physical quantity– a measuring instrument designed to reproduce and (or) store a physical quantity of one or more specified dimensions, the values ​​of which are expressed in established units and are known with the required accuracy. Examples of measures: weights, measuring resistors, gauge blocks, radionuclide sources, etc.

Measures that reproduce physical quantities of only one size are called unambiguous(weight), several sizes – polysemantic(millimeter ruler - allows you to express length in both mm and cm). In addition, there are sets and stores of measures, for example, a store of capacitances or inductances.

When making measurements using measures, the measured quantities are compared with known quantities reproduced by the measures. Comparison is carried out in different ways, the most common means of comparison is comparator, intended for comparison of measures of homogeneous quantities. An example of a comparator is a lever scale.

Measures include standard samples and reference substance, which are specially designed bodies or samples of a substance of a certain and strictly regulated content, one of the properties of which is a quantity with a known value. For example, samples of hardness, roughness.

Measuring transducer (MT) - a technical device with standard metrological characteristics, used to convert a measured quantity into another quantity or measuring signal, convenient for processing, storage, display or transmission. The measuring information at the output of the MT, as a rule, is not available for direct perception by the observer. Although PIs are structurally separate elements, they are most often included as components in more complex measuring instruments or installations and do not have independent significance when carrying out measurements.

The converted quantity supplied to the measuring transducer is called input, and the result of the transformation is day off size. The relationship between them is given transformation function, which is its main metrological characteristic.

To directly reproduce the measured value, use primary converters, which are directly affected by the measured value and in which the transformation of the measured value occurs for its further transformation or indication. An example of a primary transducer is a thermocouple in a thermoelectric thermometer circuit. One type of primary converter is sensor– a structurally separate primary transducer from which measuring signals are received (it “gives” information). The sensor can be placed at a considerable distance from the measuring instrument that receives its signals. For example, a weather balloon sensor. In the field of ionizing radiation measurements, a sensor is often called a detector.

By the nature of the transformation, individual entrepreneurs can be analog, analog-to-digital (ADC), digital-to-analog (DAC), that is, converting a digital signal into an analogue one or vice versa. In an analog form of representation, a signal can take on a continuous set of values, that is, it is a continuous function of the measured value. In digital (discrete) form, it is represented as digital groups or numbers. Examples of MTs are measuring current transformers and resistance thermometers.

Measuring device– a measuring instrument designed to obtain the values ​​of a measured physical quantity within a specified range. The measuring instrument presents measurement information in a form accessible to direct perception observer.

By indication method differentiate indicating and recording instruments. Registration can be carried out in the form of a continuous recording of the measured value or by printing the instrument readings in digital form.

Devices direct action display the measured quantity on a indicating device having graduations in units of this quantity. For example, ammeters, thermometers.

Comparison devices are intended for comparison of measured quantities with quantities whose values ​​are known. Such instruments are used for measurements with greater accuracy.

According to their action, measuring instruments are divided into integrating and summing, analog and digital, recording and printing.

Measuring setup and system– a set of functionally combined measures, measuring instruments and other devices intended for measuring one or more quantities and located in one place ( installation) or in different places of the measured object ( system). Measuring systems are generally automated and essentially they provide automation of the processes of measurement, processing and presentation of measurement results. An example of measuring systems are automated radiation monitoring systems (ARMS) at various nuclear physics facilities, such as, for example, nuclear reactors or charged particle accelerators.

By metrological purposes measuring instruments are divided into working and standards.

Working SI- a measuring instrument intended for measurements that is not associated with the transfer of unit size to other measuring instruments. The working measuring instrument can also be used as an indicator. Indicator– a technical means or substance intended to determine the presence of any physical quantity or the excess of its threshold value. The indicator does not have standardized metrological characteristics. Examples of indicators are oscilloscope, litmus paper, etc.

Reference- a measuring instrument designed to reproduce and (or) store a unit and transfer its size to other measuring instruments. Among them we can highlight working standards different categories, which were previously called exemplary measuring instruments.

Classification of measuring instruments is carried out according to various other criteria. For example, according to types of measured quantities, by type of scale (with a uniform or uneven scale), by connection with the measurement object (contact or non-contact

When performing various works on metrological support of measurements, specific categories are used, which also need to be defined. These categories are:

Certification - checking the metrological characteristics (measurement error, accuracy, reliability, correctness) of a real measuring instrument.

Certification - checking the compliance of the measuring instrument with the standards of a given country, a given industry with the issuance of a document-certificate of conformity. During certification, in addition to the metrological characteristics, all points contained in the scientific and technical documentation for this measuring instrument are subject to verification. These may include requirements for electrical safety, environmental safety, and the impact of changes in climatic parameters. It is mandatory to have methods and means for verifying this measuring instrument.

Verification - periodic monitoring of errors in the readings of measuring instruments using measuring instruments of a higher accuracy class (standard instruments or standard measure). As a rule, verification ends with the issuance of a verification certificate or branding of the measuring instrument or the measure being verified.

Graduation - placing marks on the instrument scale or obtaining the dependence of the digital indicator readings on the value of the measured physical quantity. Often in technical measurements, calibration is understood as periodic monitoring of the performance of a device using measures that do not have metrological status or using special devices built into the device. Sometimes this procedure is called calibration, and this word is written on the operating panel of the device.

This term is actually used in metrology, and calibration according to standards is called a slightly different procedure.

Calibrating a measure or set of measures - verification of a set of single-valued measures or a multi-valued measure at various scale marks. In other words, calibration is the verification of a measure through cumulative measurements. Sometimes the term “calibration” is used as a synonym for verification, but only such verification can be called calibration in which several measures or scale divisions are compared with each other in various combinations.

Reference – a measuring instrument intended for reproducing and storing a unit of quantity for the purpose of transferring it to means of measuring a given quantity.

Primary standard ensures the reproducibility of the unit under special conditions.

Secondary standard– standard is the resulting unit size by comparison with the primary standard.

Third standard– comparison standard – this secondary standard is used to compare standards that, for one reason or another, cannot be compared with each other.

Fourth standard– the working standard is used to directly convey the size of the unit.

Verification and calibration tools.

Verification of measuring instruments- a set of operations performed by the state metrological service bodies (other authorized bodies and organizations) in order to determine and confirm the compliance of the measuring instrument with the established technical requirements.

Measuring instruments subject to state metrological control and supervision are subject to verification upon release from production or repair, upon import for import and operation.

Calibration of measuring instrument- a set of operations performed to determine the actual values ​​of metrological characteristics and (or) suitability for use of a measuring instrument that is not subject to state metrological control and supervision. Measuring instruments that are not subject to verification may be subject to calibration upon release from production or repair, upon import for import and operation.

VERIFICATION measuring instruments - a set of operations performed by the bodies of the state metrological service (other authorized bodies, organizations) in order to determine and confirm the compliance of the measuring instrument with the established technical requirements.

Responsibility for improper performance of verification work and non-compliance with the requirements of relevant regulatory documents lies with the relevant body of the State Metrological Service or the legal entity whose metrological service performed the verification work.

Positive results of verification of measuring instruments are certified by a verification mark or verification certificate.

The form of the verification mark and verification certificate, the procedure for applying the verification mark is established by the Federal Agency for Technical Regulation and Metrology.

In Russia, verification activities are regulated by the Law of the Russian Federation “On Ensuring the Uniformity of Measurements” and many other by-laws.

Verification- establishing the suitability of measuring equipment falling under State Metrological Supervision for use by monitoring their metrological characteristics.

Interstate Council for Standardization, Metrology and Certification (countries CIS) the following types of verification are established

Primary verification is a verification performed when a measuring instrument is released from production or after repair, as well as when a measuring instrument is imported from abroad in batches, upon sale.

Periodic verification - verification of measuring instruments in operation or storage, carried out at established inter-verification intervals.

Extraordinary verification - Verification of a measuring instrument carried out before the deadline for its next periodic verification.

Inspection verification - verification carried out by an authority state metrological service when conducting state supervision over the condition and use of measuring instruments.

Complete verification - verification in which the metrological characteristics means of measurement inherent in it as a whole.

Element-by-element verification is a verification in which the values ​​of the metrological characteristics of measuring instruments are established based on the metrological characteristics of its elements or parts.

Selective verification is verification of a group of measuring instruments randomly selected from a batch, based on the results of which the suitability of the entire batch is judged.

Verification diagrams.

To ensure the correct transfer of the dimensions of units of measurement from the standard to the working measuring instruments, verification schemes are drawn up that establish metrological subordination of the state standard, digit standards and working measuring instruments.

Verification schemes are divided into state and local. State verification schemes apply to all measuring instruments of this type used in the country. Local verification schemes are intended for metrological bodies of ministries; they also apply to measuring instruments of subordinate enterprises. In addition, a local diagram can be drawn up for the measuring instruments used at a particular enterprise. All local verification schemes must comply with the requirements of subordination, which are determined by the state verification scheme. State verification schemes are developed by research institutes of the State Standard of the Russian Federation, holders of state standards.

In some cases, it may be impossible to reproduce the entire range of values ​​with one standard; therefore, the circuit may provide several primary standards, which together reproduce the entire measurement scale. For example, the temperature scale from 1.5 to 1*10 5 K is reproduced by two state standards.

Verification diagram for measuring instruments - a normative document establishing the subordination of measuring instruments involved in the transfer of unit size from the standard to working measuring instruments (indicating methods and errors during transmission). There are state and local verification schemes; previously there were also departmental verification schemes.

The state verification scheme applies to all measuring instruments of a given physical quantity used in the country, for example, to measuring instruments of electrical voltage in a certain frequency range. By establishing a multi-stage procedure for transferring the size of a PV unit from the state standard, requirements for means and methods of verification, the state verification scheme represents, as it were, the structure of metrological support for a certain type of measurement in the country. These schemes are developed by the main centers of standards and are formalized by one GOST GSI.

Local verification schemes apply to measuring instruments that are subject to verification by a given metrological department at an enterprise that has the right to verify measuring instruments and are formalized in the form of an enterprise standard. Departmental and local verification schemes should not contradict state ones and should take into account their requirements in relation to the specifics of a particular enterprise.

The departmental verification scheme is developed by the departmental metrological service body, agreed with the main center of standards - the developer of the state verification scheme for measuring instruments of a given PV and applies only to measuring instruments subject to intradepartmental verification.

Metrological characteristics of measuring instruments.

Metrological characteristic of a measuring instrument is a characteristic of one of the properties of a measuring instrument that affects the measurement result or its error. The main metrological characteristics are the measurement range and various components of the measuring instrument error.