What does the science of metrology study? Basic concepts and definitions in metrology. Non-system unit fv

Basic metrology terms are established by state standards.

1. Basic concept of metrology - measurement. According to GOST 16263-70, measurement is finding a value physical quantity(FV) experimentally using special technical means.

The result of a measurement is the receipt of a value during the measurement process.

With the help of measurements, information is obtained about the state of production, economic and social processes. For example, measurements are the main source of information about the compliance of products and services with the requirements of regulatory documentation during certification.

2. Measuring instrument(SI) - a special technical means that stores a unit of quantity for comparing the measured quantity with its unit.

3. Measure is a measuring instrument designed to reproduce a physical quantity of a given size: weights, gauge blocks.

To assess the quality of measurements, the following measurement properties are used: accuracy, convergence, reproducibility and accuracy.

- Correctness- the property of measurements when their results are not distorted by systematic errors.

- Convergence- a property of measurements that reflects the closeness to each other of measurement results performed under the same conditions, by the same measuring instruments, by the same operator.

- Reproducibility- a property of measurements that reflects the closeness to each other of the results of measurements of the same quantity, performed under different conditions - at different times, in different places, with different methods and measuring instruments.

For example, the same resistance can be measured directly with an ohmmeter, or with an ammeter and a voltmeter using Ohm's law. But, naturally, in both cases the results should be the same.

- Accuracy- a property of measurements that reflects the proximity of their results to the true value of the measured value.

This is the main property of measurements, because most widely used in the practice of intentions.

The accuracy of SI measurements is determined by their error. High measurement accuracy corresponds to small errors.

4. Error is the difference between the SI readings (measurement result) Xmeas and the true (actual) value of the measured physical quantity Xd.

The task of metrology is to ensure the uniformity of measurements. Therefore, to generalize all the above terms, use the concept uniformity of measurements- a state of measurements in which their results are expressed in legal units, and errors are known with a given probability and do not go beyond established limits.

Measures to actually ensure the uniformity of measurements in most countries of the world are established by law and are part of the functions of legal metrology. In 1993, the Russian Federation Law “On Ensuring the Uniformity of Measurements” was adopted.

Previously, legal norms were established by government regulations.

Compared to the provisions of these resolutions, the Law established the following innovations:

In terminology - outdated concepts and terms have been replaced;

In licensing metrological activities in the country, the right to issue a license is granted exclusively to the bodies of the State Metrological Service;

A unified verification of measuring instruments has been introduced;

A clear separation of the functions of state metrological control and state metrological supervision has been established.

An innovation is also the expansion of the scope of state metrological supervision to banking, postal, tax, customs operations, as well as to mandatory certification of products and services;

Calibration rules have been revised;

Voluntary certification of measuring instruments has been introduced, etc.

Prerequisites for the adoption of the law:

The country's transition to a market economy;

As a result, the reorganization of state metrological services;

This led to a violation centralized system management of metrological activities and departmental services;

Problems arose during state metrological supervision and control due to the emergence of various forms property;

Thus, the problem of revising the legal, organizational, and economic foundations of metrology has become very urgent.

The objectives of the Law are as follows:

Protecting citizens and the economy Russian Federation from the negative consequences of unreliable measurement results;

Promoting progress based on the use of state standards of units of quantities and the use of measurement results of guaranteed accuracy;

Creating favorable conditions for the development of international relations;

Regulation of relations between government bodies of the Russian Federation and legal entities and individuals on issues of manufacturing, production, operation, repair, sale and import of measuring instruments.

Consequently, the main areas of application of the Law are trade, healthcare, protection environment, foreign economic activity.

The task of ensuring the uniformity of measurements is assigned to the State Metrological Service. The law determines the intersectoral and subordinate nature of its activities.

The intersectoral nature of the activity means the legal status of the State Metrological Service is similar to other control and supervisory authorities government controlled(Gosatomnadzor, Gosenergonadzor, etc.).

The subordinate nature of its activities means vertical subordination to one department - Gosstandart of Russia, within the framework of which it exists separately and autonomously.

In pursuance of the adopted Law, the Government of the Russian Federation in 1994 approved a number of documents:

- “Regulations on state scientific and metrological centers”,

- “The procedure for approving regulations on metrological services of federal executive authorities and legal entities”,

- “The procedure for accreditation of metrological services of legal entities for the right to verify measuring instruments”,

These documents, together with the specified Law, are the main legal acts on metrology in Russia.

Metrology

Metrology(from Greek μέτρον - measure, + other Greek λόγος - thought, reason) - The subject of metrology is the extraction of quantitative information about the properties of objects with a given accuracy and reliability; the regulatory framework for this is metrological standards.

Metrology consists of three main sections:

Theoretical or fundamental - considers general theoretical problems (development of the theory and problems of measuring physical quantities, their units, measurement methods).
Applied- studies questions practical application developments in theoretical metrology. She is in charge of all issues metrological support.
Legislative- establishes mandatory technical and legal requirements for the use of units of physical quantities, methods and measuring instruments.

Metrologist

Goals and objectives of metrology

Creation general theory measurements;
formation of units of physical quantities and systems of units;
development and standardization of methods and measuring instruments, methods for determining measurement accuracy, the basis for ensuring the uniformity of measurements and uniformity of measuring instruments (the so-called “legal metrology”);
creation of standards and exemplary measuring instruments, verification of measures and measuring instruments. The priority subtask of this direction is to develop a system of standards based on physical constants.

Metrology also studies the development of a system of measures, monetary units and counting in a historical perspective.

Axioms of metrology

Any measurement is a comparison.
Any measurement without a priori information is impossible.
The result of any measurement without rounding the value is a random variable.

Metrology terms and definitions

Unity of measurements- a state of measurements, characterized by the fact that their results are expressed in legal units, the sizes of which, within established limits, are equal to the sizes of units reproduced by primary standards, and the errors of the measurement results are known and with a given probability do not go beyond the established limits.
Physical quantity- one of the properties of a physical object, common in qualitative terms for many physical objects, but in quantitative terms individual for each of them.
Measurement- a set of operations for the use of a technical means that stores a unit of physical quantity, ensuring the determination of the relationship of the measured quantity with its unit and obtaining the value of this quantity.
Measuring instrument- a technical device intended for measurements and having standardized metrological characteristics reproducing and (or) storing a unit of quantity, the size of which is assumed to be unchanged within the limits of the established error over a known time interval.
Verification- a set of operations performed to confirm the compliance of measuring instruments with metrological requirements.
Measurement error- deviation of the measurement result from the true value of the measured value.
Measuring instrument error- the difference between the reading of the measuring instrument and the actual value of the measured physical quantity.
Measuring instrument accuracy- characteristic of the quality of a measuring instrument, reflecting the proximity of its error to zero.
License- this is a permit issued by the state metrological service authorities on the territory assigned to it to an individual or legal entity to carry out activities for the production and repair of measuring instruments.
Standard unit of quantity- a technical means intended for transmission, storage and reproduction of a unit of value.

History of metrology

Metrology dates back to ancient times and is even mentioned in the Bible. Early forms of metrology involved the establishment of simple arbitrary standards by local authorities, often based on simple practical measurements such as arm length. The earliest standards were introduced for quantities such as length, weight and time, this was done to simplify commercial transactions as well as registration human activity.

Metrology acquired a new meaning during the era of the industrial revolution; it became absolutely necessary to ensure mass production.

Historically important stages in the development of metrology:

XVIII century - establishment of the meter standard (the standard is kept in France, in the Museum of Weights and Measures; currently it is more of a historical exhibit than a scientific instrument);
1832 - creation of absolute systems of units by Carl Gauss;
1875 - signing of the international Meter Convention;
1960 - development and installation International system units (SI);
20th century - metrological studies of individual countries are coordinated by International Metrological Organizations.

Milestones national history metrology:

accession to the Meter Convention;
1893 - creation by D. I. Mendeleev of the Main Chamber of Weights and Measures ( modern name: “Research Institute of Metrology named after. Mendeleev");

World Metrology Day is celebrated annually on May 20. The holiday was established by the International Committee of Weights and Measures (CIPM) in October 1999, at the 88th meeting of the CIPM.

The formation and differences of metrology in the USSR (Russia) and abroad

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, as 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, GOST regulation of everything that needs to be standardized. Abroad, non-governmental organizations such as ASTM have taken on this task.

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 an objectionable standard or instrument and agree with its partners on another option for certifying the reproducibility of measurements.

Selected areas of metrology

Aviation metrology
Chemical metrology
Medical metrology
Biometrics

The science of measurements, methods and means of ensuring their unity and ways of achieving the required accuracy.

MEASUREMENT

UNITY OF MEASUREMENT

1. Physical quantities

PHYSICAL QUANTITY (PV)

ACTUAL PV VALUE

PHYSICAL PARAMETER

Influential fv

ROD FV

Qualitative certainty FV.

Part length and diameter-

UNIT FV

PV UNITS SYSTEM

DERIVATIVE UNIT

Unit of speed- meter/second.

NON-SYSTEM UNIT FV

allowed equally;.

temporarily admitted;

withdrawn from use.

For example:

- - units of time;

in optics- diopter- - hectare- - unit of energy, etc.;

- revolutions per second; bar- pressure unit (1bar = 100 000 Pa);

quintal, etc.

MULTIPLE UNIT OF FV

DOLNAYA FV

For example, 1µs= 0.000 001s.

Basic terms and definitions metrology

The science of measurements, methods and means of ensuring their unity and ways of achieving the required accuracy.

MEASUREMENT

Finding the value of a measured physical quantity experimentally using special technical means.

UNITY OF MEASUREMENT

A characteristic of the quality of measurements, which consists in the fact that their results are expressed in legal units, and the errors of the measurement results are known with a given probability and do not go beyond the established limits.

ACCURACY OF MEASUREMENT RESULTS

A characteristic of the quality of a measurement, reflecting the closeness to zero of the error of its result.

1. Physical quantities

PHYSICAL QUANTITY (PV)

Characteristics of one of the properties of a physical object ( physical system, phenomenon or process), common in qualitative terms to many physical objects, but quantitatively individual for each object.

THE TRUE VALUE OF A PHYSICAL QUANTITY

The value of a physical quantity that ideally reflects the corresponding physical quantity in qualitative and quantitative terms.

This concept is correlated with the concept of absolute truth in philosophy.

ACTUAL PV VALUE

The value of the PV, found experimentally and so close to the true value that for the given measurement task it can replace it.

When checking measuring instruments, for example, the actual value is the value of the standard measure or the reading of the standard measuring instrument.

PHYSICAL PARAMETER

EF, considered when measuring a given EF as an auxiliary characteristic.

For example, frequency when measuring AC voltage.

Influential fv

PV, the measurement of which is not provided for by a given measuring instrument, but which influences the measurement results.

ROD FV

Qualitative certainty FV.

Part length and diameter- homogeneous quantities; the length and mass of the part are non-uniform quantities.

UNIT FV

A PV of a fixed size, which is conventionally assigned a numerical value equal to one, and is used for the quantitative expression of homogeneous PV.

There must be as many units as there are PVs.

There are basic, derivative, multiple, submultiple, systemic and non-systemic units.

PV UNITS SYSTEM

A set of basic and derived units of physical quantities.

BASIC UNIT OF THE SYSTEM OF UNITS

The unit of basic PV in a given system of units.

Basic units of the International System of Units SI: meter, kilogram, second, ampere, kelvin, mole, candela.

ADDITIONAL UNIT SYSTEM OF UNITS

There is no strict definition. In the SI system, these are the units of plane - radians - and solid - steradians - angles.

DERIVATIVE UNIT

A unit of a derivative of a PV system of units, formed in accordance with an equation connecting it with the basic units or with the basic and already defined derived units.

Unit of speed- meter/second.

NON-SYSTEM UNIT FV

The PV unit is not included in any of the accepted systems of units.

Non-systemic units in relation to the SI system are divided into four types:

allowed equally;.

approved for use in special areas;

temporarily admitted;

withdrawn from use.

For example:

ton: degree, minute, second- angle units; liter; minute, hour, day, week, month, year, century- units of time;

in optics- diopter- unit of measurement of optical power; in agriculture- hectare- unit of area; in physics electron-volt- unit of energy, etc.;

in maritime navigation, nautical mile, knot; in other areas- revolutions per second; bar- pressure unit (1bar = 100 000 Pa);

kilogram-force per square centimeter; millimeter of mercury; Horsepower;

quintal, etc.

MULTIPLE UNIT OF FV

A PV unit is an integer number of times larger than a system or non-system unit.

For example, frequency unit 1 MHz = 1,000,000 Hz

DOLNAYA FV

A PV unit is an integer number of times smaller than a system or non-system unit.

For example, 1µs= 0.000 001s.

Basic terms and definitions in metrology

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

Direct measurement– a measurement in which the desired value of a physical quantity is obtained directly.

Indirect measurement– determination of the desired value of a physical quantity based on the results of direct measurements of other physical quantities that are functionally related to the desired quantity.

The true value of a physical quantity– the value of a physical quantity that ideally characterizes the corresponding physical quantity in qualitative and quantitative terms.

Real value of a physical quantity– the value of a physical quantity obtained experimentally and so close to the true value that it can be used instead of it in the given measurement task.

Measured physical quantity– physical quantity to be measured in accordance with the main purpose of the measurement task.

Influential physical quantity– a physical quantity that influences the size of the measured quantity and (or) the result of measurements.

Normal range of influence quantity– the range of values of the influencing quantity, within which the change in the measurement result under its influence can be neglected in accordance with established accuracy standards.

Working range of influencing quantities– range of values of the influencing quantity, within which the additional error or change in the readings of the measuring instrument is normalized.

Measuring signal– a signal containing quantitative information about the measured physical quantity.

Scale division price– the difference in values corresponding to two adjacent scale marks.

Measuring instrument reading range– range of instrument scale values, limited by the initial and final scale values.

Measuring range– range of values of a quantity within which the permissible error limits of the measuring instrument are normalized.

Variation in meter readings– the difference in instrument readings at the same point in the measurement range with a smooth approach to this point from smaller and larger values of the measured quantity.

Transducer conversion factor– the ratio of the signal at the output of the measuring transducer, which displays the measured value, to the signal causing it at the input of the transducer.

Sensitivity of the measuring instrument– property of a measuring instrument, determined by the ratio of the change in the output signal of this instrument to the change in the measured value that causes it

Absolute error of the measuring instrument– the difference between the reading of a measuring instrument and the true (actual) value of the measured quantity, expressed in units of the measured physical quantity.

Relative error of the measuring instrument– error of a measuring instrument, expressed as the ratio of the absolute error of the measuring instrument to the measurement result or to the actual value of the measured physical quantity.

Reduced error of the measuring instrument– relative error, expressed as the ratio of the absolute error of the measuring instrument to the conventionally accepted value of a quantity (or standard value), constant over the entire measurement range or in part of the range. Often the reading range or upper measurement limit is taken as the normalizing value. The given error is usually expressed as a percentage.

Systematic error of the measuring instrument– component of the error of a measuring instrument, taken as constant or naturally varying.

Random error of the measuring instrument– component of the error of the measuring instrument, varying randomly.

Basic error of the measuring instrument– error of the measuring instrument used under normal conditions.

Additional error of the measuring instrument– a component of the error of a measuring instrument that arises in addition to the main error as a result of the deviation of any of the influencing quantities from its normal value or as a result of going beyond the normal range of values.

Limit of permissible error of measuring instrument– the greatest value of the error of measuring instruments, established by a regulatory document for a given type of measuring instrument, at which it is still recognized as suitable for use.

Accuracy class of measuring instrument– a generalized characteristic of a given type of measuring instrument, usually reflecting the level of their accuracy, expressed by the limits of permissible main and additional errors, as well as other characteristics affecting the accuracy.

Measurement result error– deviation of the measurement result from the true (actual) value of the measured quantity.

Miss (gross measurement error)– the error of the result of an individual measurement included in a series of measurements, which, for given conditions, differs sharply from the other results of this series.

Measurement method error– component of the systematic measurement error due to the imperfection of the adopted measurement method.

Amendment– the value of the quantity entered into the uncorrected measurement result in order to eliminate the components of the systematic error. The sign of the correction is opposite to the sign of the error. The correction introduced into the reading of a measuring device is called an amendment to the reading of the device.

Basic terms and definitions metrology

The science of measurements, methods and means of ensuring their unity and ways of achieving the required accuracy.

MEASUREMENT

Finding the value of a measured physical quantity experimentally using special technical means.

UNITY OF MEASUREMENT

ACCURACY OF MEASUREMENT RESULTS

A characteristic of the quality of a measurement, reflecting the closeness to zero of the error of its result.

1. Physical quantities

PHYSICAL QUANTITY (PV)

A characteristic of one of the properties of a physical object (physical system, phenomenon or process), which is qualitatively common to many physical objects, but quantitatively individual for each object.

THE TRUE VALUE OF A PHYSICAL QUANTITY

The value of a physical quantity that ideally reflects the corresponding physical quantity in qualitative and quantitative terms.

This concept is correlated with the concept of absolute truth in philosophy.

ACTUAL PV VALUE

The value of the PV, found experimentally and so close to the true value that for the given measurement task it can replace it.

When checking measuring instruments, for example, the actual value is the value of the standard measure or the reading of the standard measuring instrument.

PHYSICAL PARAMETER

EF, considered when measuring a given EF as an auxiliary characteristic.

For example, frequency when measuring AC voltage.

Influential fv

PV, the measurement of which is not provided for by a given measuring instrument, but which influences the measurement results.

ROD FV

Qualitative certainty FV.

Part length and diameter- homogeneous quantities; the length and mass of the part are non-uniform quantities.

UNIT FV

A PV of a fixed size, which is conventionally assigned a numerical value equal to one, and is used for the quantitative expression of homogeneous PV.

There must be as many units as there are PVs.

There are basic, derivative, multiple, submultiple, systemic and non-systemic units.

PV UNITS SYSTEM

A set of basic and derived units of physical quantities.

BASIC UNIT OF THE SYSTEM OF UNITS

The unit of basic PV in a given system of units.

Basic units of the International System of Units SI: meter, kilogram, second, ampere, kelvin, mole, candela.

ADDITIONAL UNIT SYSTEM OF UNITS

There is no strict definition. In the SI system, these are the units of plane - radians - and solid - steradians - angles.

DERIVATIVE UNIT

A unit of a derivative of a PV system of units, formed in accordance with an equation connecting it with the basic units or with the basic and already defined derived units.

Unit of speed- meter/second.

NON-SYSTEM UNIT FV

The PV unit is not included in any of the accepted systems of units.

Non-systemic units in relation to the SI system are divided into four types:

allowed equally;.

approved for use in special areas;

temporarily admitted;

withdrawn from use.

For example:

ton: degree, minute, second- angle units; liter; minute, hour, day, week, month, year, century- units of time;

in optics- diopter- unit of measurement of optical power; in agriculture- hectare- unit of area; in physics electron-volt- unit of energy, etc.;

in maritime navigation, nautical mile, knot; in other areas- revolutions per second; bar- pressure unit (1bar = 100 000 Pa);

kilogram-force per square centimeter; millimeter of mercury; Horsepower;

quintal, etc.

MULTIPLE UNIT OF FV

A PV unit is an integer number of times larger than a system or non-system unit.

For example, frequency unit 1 MHz = 1,000,000 Hz

DOLNAYA FV

A PV unit is an integer number of times smaller than a system or non-system unit.

For example, 1µs= 0.000 001s.

Metrology Basic terms and definitions

UDC 389.6(038):006.354 Group T80

STATE SYSTEM FOR ENSURING THE UNIFORMITY OF MEASUREMENTS

State system for ensuring the uniformity of measurements.

Metrology. Basic terms and definitions

ISS 01.040.17

Date of introduction 2001-01-01

Preface

1 DEVELOPED by the All-Russian Scientific Research Institute of Metrology named after. D.I. Mendeleev Gosstandart of Russia

INTRODUCED by the Technical Secretariat of the Interstate Council for Standardization, Metrology and Certification

2 ADOPTED by the Interstate Council for Standardization, Metrology and Certification (Minutes No. 15 of May 26-28, 1999)

State name	Name of the national standardization body
The Republic of Azerbaijan	Azgosstandart
Republic of Armenia	Armgosstandard
Republic of Belarus	State Standard of Belarus
	Gruzstandart
The Republic of Kazakhstan	Gosstandart of the Republic of Kazakhstan
The Republic of Moldova	Moldovastandard
Russian Federation	Gosstandart of Russia
The Republic of Tajikistan	Tajikgosstandart
Turkmenistan	Main State Inspectorate of Turkmenistan
The Republic of Uzbekistan	Uzgosstandart
	State Standard of Ukraine

3 By Decree of the State Committee of the Russian Federation for Standardization and Metrology dated May 17, 2000 No. 139-st, interstate Recommendations RMG 29-99 were put into effect directly as Recommendations for Metrology of the Russian Federation from January 1, 2001.

4 INSTEAD GOST 16263-70

5 REPUBLICATION. September 2003

Amendment No. 1 was introduced, adopted by the Interstate Council for Standardization, Metrology and Certification (Minutes No. 24 of December 5, 2003) (IUS No. 1 of 2005)

Introduction

The terms established by these recommendations are arranged in a systematic order, reflecting the established system of basic concepts of metrology. Terms are given in sections 2-13. Each section contains continuous numbering of terms.

For each concept, one term is established, which has a terminological article number. A significant number of terms are accompanied by their short forms and (or) abbreviations, which should be used in cases that exclude the possibility of their different interpretations.

Terms that have the number of a terminological article are typed in bold, their short forms and abbreviations are in light. Terms appearing in the notes are in italics.

In the alphabetical index of terms in Russian, the specified terms are listed in alphabetical order, indicating the number of the terminological article (for example, “value 3.1”). In this case, for terms given in the notes, the letter “p” is indicated after the article number (for example, legalized units 4.1 p).

For many established terms, foreign language equivalents are provided in German (de), English (en) and French (fr). They are also listed in alphabetical indexes of equivalent terms in German, English and French.

The word “applied” in term 2.4, given in brackets, as well as the words of a number of foreign language equivalents of terms given in brackets, can be omitted if necessary.

The concept of “additional unit” is not defined, since the term fully discloses its content.

What is metrology and why does humanity need it?

Metrology - the science of measurements

Metrology is the science of measurements, methods and means of ensuring their unity and ways of achieving the required accuracy.
This is a science that deals with establishing units of measurement of various physical quantities and reproducing their standards, developing methods for measuring physical quantities, as well as analyzing the accuracy of measurements and investigating and eliminating the causes of errors in measurements.

In practical life, people deal with measurements everywhere. Measurements of such quantities as length, volume, weight, time, etc. are encountered at every step and have been known since time immemorial. Of course, the methods and means of measuring these quantities in ancient times were primitive and imperfect, however, without them it is impossible to imagine the evolution of Homo sapiens .

The importance of measurements in modern society. They serve not only as the basis of scientific and technical knowledge, but are of paramount importance for accounting of material resources and planning, for internal and foreign trade, to ensure product quality, interchangeability of components and parts and improvement of technology, to ensure labor safety and other types of human activity.

Metrology has great importance for the progress of natural and technical sciences, since increasing the accuracy of measurements is one of the means of improving the ways of human knowledge of nature, discoveries and practical application of accurate knowledge.
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.

Objectives of the science of metrology

Since metrology studies methods and means of measuring physical quantities with the maximum degree of accuracy, its tasks and goals follow from the very definition of science. However, given the enormous importance of metrology as a science for scientific and technological progress and the evolution of human society, all terms and definitions of metrology, including its goals and objectives, are standardized through regulatory documents - GOST ov.
So, the main tasks of metrology (according to GOST 16263-70) are:

· establishment of units of physical quantities, state standards and standard measuring instruments;

· development of theory, methods and means of measurement and control;

· ensuring the uniformity of measurements and uniform measuring instruments;

· development of methods for assessing errors, the state of measuring and control equipment;

· development of methods for transferring unit sizes from standards or reference measuring instruments to working measuring instruments.

LECTURE No. 1. Metrology

Subject and tasks of metrology

Over the course of world history, man had to measure various things, weigh food, and count time. For this purpose, it was necessary to create a whole system of various measurements necessary to calculate volume, weight, length, time, etc. Data from such measurements help to master the quantitative characteristics of the surrounding world. The role of such measurements in the development of civilization is extremely important. No industry today National economy could not function correctly and productively without the use of its measurement system. After all, it is with the help of these measurements that the formation and management of various technological processes, as well as monitoring the quality of products. Such measurements are needed for a variety of needs in the process of developing scientific and technological progress: for accounting of material resources and planning, and for the needs of domestic and foreign trade, and for checking the quality of products, and for increasing the level of labor protection of any working person. Despite the diversity natural phenomena and products of the material world, for their measurement there is the same diverse system of measurements, based on a very significant point - comparison of the resulting value with another, similar to it, which was once accepted as a unit. With this approach, a physical quantity is regarded as a certain number of units accepted for it, or, in other words, its value is thus obtained. There is a science that systematizes and studies such units of measurement - metrology. As a rule, metrology means the science of measurement, existing means and methods that help to observe the principle of their unity, as well as ways to achieve the required accuracy.

The origin of the very term “metrology” is erecting! to two Greek words: metron, which translates as “measure,” and logos, “teaching.” The rapid development of metrology occurred at the end of the 20th century. It is inextricably linked with the development of new technologies. Before this, metrology was only descriptive scientific subject. It should also be noted that D.I. Mendeleev took part in the creation of this discipline, who was closely involved in metrology from 1892 to 1907... when he led this industry Russian science. Thus, we can say that metrology studies:

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

2) measurements of physical quantities and technical parameters, as well as the properties and composition of substances;

3) measurements for monitoring and regulation of technological processes.

There are several main areas of metrology:

1) general measurement theory;

2) systems of units of physical quantities;

3) methods and means of measurement;

4) methods for determining measurement accuracy;

5) the basis for ensuring the uniformity of measurements, as well as the basis for the uniformity of measuring instruments;

6) standards and exemplary measuring instruments;

7) methods for transferring unit sizes from samples of measuring instruments and from standards to working measuring instruments. An important concept in the science of metrology is the unity of measurements, which means such measurements in which the final data are obtained in legal units, while the errors of the measurement data are obtained with a given probability. The need for uniformity of measurements is caused by the possibility of comparing the results of various measurements that were carried out in different areas, in different time periods, as well as using various methods and measuring instruments.

Metrology objects should also be distinguished:

1) units of measurement of quantities;

2) measuring instruments;

3) techniques used to perform measurements, etc.

Metrology includes: firstly, general rules, norms and requirements, secondly, issues that require government regulation and control. And here we are talking about:

1) physical quantities, their units, as well as their measurements;

2) principles and methods of measurements and measuring equipment;

3) errors of measuring instruments, methods and means of processing measurement results in order to eliminate errors;

4) ensuring the uniformity of measurements, standards, samples;

5) state metrological service;

6) methodology of verification schemes;

7) working measuring instruments.

In this regard, the tasks of metrology become: improvement of standards, development of new methods of precise measurements, ensuring the unity and necessary accuracy of measurements.

Terms

A very important factor in the correct understanding of the discipline and science of metrology are the terms and concepts used in it. It must be said that their correct formulation and interpretation are of paramount importance, since the perception of each person is individual and he interprets many, even generally accepted terms, concepts and definitions in his own way, using his life experience and following his instincts, his life credo. And for metrology, it is very important to interpret the terms unambiguously for everyone, since this approach makes it possible to optimally and completely understand any life phenomenon. For this purpose, a special terminology standard was created, approved at the state level. Since Russia currently perceives itself as part of the global economic system, work is constantly underway to unify terms and concepts, and an international standard is being created. This certainly helps facilitate the process of mutually beneficial cooperation with highly developed foreign countries and partners. So, in metrology the following quantities and their definitions are used:

1) physical quantity, representing general property regarding quality large quantity physical objects, but individual for each in the sense of quantitative expression;

2) unit of physical quantity, which implies a physical quantity, which by condition is assigned a numerical value equal to one;

3) measurement of physical quantities, by which we mean the quantitative and qualitative assessment of a physical object using measuring instruments;

4) measuring instrument, which is a technical device that has standardized metrological characteristics. These include a measuring device, a measure, a measuring system, a measuring transducer, a set of measuring systems;

5) measuring device is a measuring instrument that produces an information signal in a form that would be understandable for direct perception by an observer;

6) measure– also a measuring instrument that reproduces a physical quantity of a given size. For example, if a device is certified as a measuring instrument, its scale with digitized marks is a measure;

7) measuring system, perceived as a set of measuring instruments that are connected to each other through information transmission channels to perform one or more functions;

8) measuring transducer– also a measuring instrument that produces an information measuring signal in a form convenient for storage, viewing and broadcasting via communication channels, but not accessible to direct perception;

9) measurement principle as a set of physical phenomena, on which measurements are based;

10) measurement method as a set of techniques and principles for using technical measuring instruments;

11) measurement technique as a set of methods and rules, developed by metrological research organizations, approved by law;

12) measurement error, representing an insignificant difference between the true values of a physical quantity and the values obtained as a result of measurement;

13) basic unit of measurement, understood as a unit of measurement, having a standard that is officially approved;

14) derived unit as a unit of measurement, associated with basic units based on mathematical models through energy relationships, without a standard;

15) reference, which is intended for storing and reproducing a unit of physical quantity, for transmitting its dimensional parameters to measuring instruments that are lower in the verification scheme. There is the concept of “primary standard”, which means a measuring instrument that has the highest accuracy in the country. There is the concept of “standard of comparison”, interpreted as a means for connecting standards of interstate services. And there is the concept of “standard-copy” as a means of measurement for transferring the sizes of units to standard means;

16) exemplary product which is understood as a measuring instrument intended only for transmitting the dimensions of units to working measuring instruments;

17) work tool, understood as “a means of measurement for assessing physical phenomenon»;

18) accuracy of measurements, interpreted as a numerical value of a physical quantity, the inverse of the error, determines the classification of standard measuring instruments. According to the accuracy of measurements, measuring instruments can be divided into: highest, high, medium, low.

Classification of measurements

Classification of measuring instruments can be carried out according to the following criteria.

1. Accuracy characteristics measurements are divided into equal and unequal.

Equal-precision measurements a physical quantity is a series of measurements of a certain quantity made using measuring instruments (MI) with the same accuracy under identical initial conditions.

Unequally accurate measurements a physical quantity is a series of measurements of a certain quantity made using measuring instruments with different accuracy and (or) under different initial conditions.

2. By number of measurements measurements are divided into single and multiple.

Single measurement is a measurement of one quantity made once. In practice, single measurements have a large error; therefore, to reduce the error, it is recommended to perform measurements of this type at least three times, and take their arithmetic average as the result.

Multiple measurements is a measurement of one or more quantities performed four or more times. A multiple measurement is a series of single measurements. The minimum number of measurements at which a measurement can be considered multiple is four. The result of multiple measurements is the arithmetic average of the results of all measurements taken. With repeated measurements, the error is reduced.

3. By type of change in value measurements are divided into static and dynamic.

Static measurements- These are measurements of a constant, unchanging physical quantity. An example of such a time-constant physical quantity is the length of a land plot.

Dynamic measurements– these are measurements of a changing, non-constant physical quantity.

4. By purpose measurements are divided into technical and metrological.

Technical measurements– these are measurements performed by technical measuring instruments.

Metrological measurements are measurements made using standards.

5. By way of presenting the result measurements are divided into absolute and relative.

Absolute measurements– these are measurements that are performed through direct, direct measurement of a fundamental quantity and (or) the application of a physical constant.

Relative measurements- these are measurements in which the ratio of homogeneous quantities is calculated, with the numerator being the quantity being compared, and the denominator being the basis of comparison (unit). The measurement result will depend on what value is taken as the basis of comparison.

6. By methods of obtaining results measurements are divided into direct, indirect, cumulative and joint.

Direct measurements– these are measurements performed using measures, i.e. the measured quantity is compared directly with its measure. An example of direct measurements is the measurement of an angle (measure - protractor).

Indirect measurements are measurements in which the value of the measurand is calculated using values obtained through direct measurements and some known relationship between these values and the measurand.

Aggregate Measurements– these are measurements, the result of which is the solution of a certain system of equations, which is composed of equations obtained as a result of measuring possible combinations of measured quantities.

Joint measurements– these are measurements during which at least two inhomogeneous physical quantities are measured in order to establish the relationship that exists between them.

Units

In 1960, at the XI General Conference on Weights and Measures, the International System of Units (SI) was approved.

The International System of Units is based on seven units covering the following fields of science: mechanics, electricity, heat, optics, molecular physics, thermodynamics and chemistry:

1) unit of length (mechanics) – meter;

2) unit of mass (mechanics) – kilogram;

3) unit of time (mechanics) – second;

4) unit of force electric current(electricity) - ampere;

5) unit of thermodynamic temperature (heat) – kelvin;

6) unit of luminous intensity (optics) – candela;

7) unit of amount of substance ( Molecular physics, thermodynamics and chemistry) – mole.

The International System of Units has additional units:

1) unit of measurement of a plane angle – radian;

2) unit of measurement of solid angle – steradian Thus, through the adoption of the International System of Units, units of measurement of physical quantities in all fields of science and technology were streamlined and brought to one type, since all other units are expressed through seven basic and two additional SI units. For example, the amount of electricity is expressed in terms of seconds and amperes.

Measurement error

In the practice of using measurements, their accuracy becomes a very important indicator, which represents the degree of closeness of the measurement results to some actual value, which is used for qualitative comparison of measurement operations. And as a quantitative assessment, as a rule, measurement error is used. Moreover, the smaller the error, the higher the accuracy is considered.

According to the law of error theory, if it is necessary to increase the accuracy of the result (with systematic error excluded) by 2 times, then the number of measurements must be increased by 4 times; if it is necessary to increase the accuracy by 3 times, then the number of measurements is increased by 9 times, etc.

The process of assessing measurement error is considered one of the most important activities in ensuring the uniformity of measurements. Naturally, there are a huge number of factors that influence the accuracy of measurement. Consequently, any classification of measurement errors is rather arbitrary, since often, depending on the conditions of the measurement process, errors can appear in different groups. Moreover, according to the principle of dependence on the form, these expressions of measurement error can be: absolute, relative and reduced.

In addition, depending on the nature of the manifestation, the causes of occurrence and the possibility of elimination, measurement errors can be components. In this case, the following components of error are distinguished: systematic and random.

The systematic component remains constant or changes with subsequent measurements of the same parameter.

The random component changes when the same parameter is changed randomly again. Both components of the measurement error (random and systematic) appear simultaneously. Moreover, the value of the random error is not known in advance, since it can arise due to a number of unspecified factors. This type of error cannot be completely eliminated, but their influence can be somewhat reduced by processing the measurement results.

Systematic error, and this is its peculiarity, when compared with random error, which is detected regardless of its sources, is considered according to its components in connection with the sources of occurrence.

The components of error can also be divided into: methodological, instrumental and subjective. Subjective systematic errors are associated with individual characteristics operator. Such an error may occur due to errors in readings or operator inexperience. Basically, systematic errors arise due to methodological and instrumental components. The methodological component of the error is determined by the imperfection of the measurement method, methods of using SI, incorrectness of calculation formulas and rounding of results. The instrumental component appears due to the intrinsic error of the SI, determined by the accuracy class, the influence of the SI on the result, and the resolution of the SI. There is also such a thing as “gross errors or misses”, which can appear due to erroneous operator actions, malfunction of measuring instrument or unforeseen changes in the measurement situation. Such errors are usually discovered in the process of reviewing measurement results using special criteria. An important element This classification is error prevention, understood as the most rational way to reduce error, which is to eliminate the influence of any factor.

Types of errors

The following types of errors are distinguished:

1) absolute error;

2) relative error;

3) reduced error;

4) basic error;

5) additional error;

6) systematic error;

7) random error;

8) instrumental error;

9) methodological error;

10) personal error;

11) static error;

12) dynamic error.

Measurement errors are classified according to the following criteria.

According to the method of mathematical expression, errors are divided into absolute errors and relative errors.

Based on the interaction of changes in time and the input value, errors are divided into static errors and dynamic errors.

Based on the nature of their occurrence, errors are divided into systematic errors and random errors.

Absolute error– this is a value calculated as the difference between the value of a quantity obtained during the measurement process and the real (actual) value of this quantity.

The absolute error is calculated using the following formula:

Q n =Q n ?Q 0 ,

where AQ n – absolute error;

Qn– the value of a certain quantity obtained during the measurement process;

Q 0– the value of the same quantity taken as the basis of comparison (real value).

Absolute error of the measure– this is a value calculated as the difference between the number, which is the nominal value of the measure, and the real (real) value of the quantity reproduced by the measure.

Relative error is a number that reflects the degree of measurement accuracy.

The relative error is calculated using the following formula:

where?Q – absolute error;

Q 0– real (real) value of the measured quantity.

The relative error is expressed as a percentage.

Reduced error is a value calculated as the ratio of the absolute error value to the normalizing value.

The standard value is determined as follows:

1) for measuring instruments for which a nominal value is approved, this nominal value is taken as the standard value;

2) for measuring instruments with null value is located at the edge of the measurement scale or outside the scale, the normalizing value is taken equal to the final value from the measurement range. The exception is measuring instruments with a significantly uneven measurement scale;

3) for measuring instruments whose zero mark is located inside the measurement range, the normalizing value is taken equal to the sum of the final numerical values of the measurement range;

4) for measuring instruments (measuring instruments) in which the scale is uneven, the normalizing value is taken equal to the whole length of the measurement scale or the length of that part of it that corresponds to the measurement range. The absolute error is then expressed in units of length.

Measurement error includes instrumental error, method error, and counting error. Moreover, the counting error arises due to the inaccuracy in determining the division fractions of the measurement scale.

Instrumental error– this is an error that arises due to errors made during the manufacturing process of functional parts of measuring instruments.

Methodological error is an error that occurs for the following reasons:

1) inaccuracy in constructing a model of the physical process on which the measuring instrument is based;

2) incorrect use of measuring instruments.

Subjective error– this is an error arising due to the low degree of qualification of the operator of the measuring instrument, as well as due to the error of the human visual organs, i.e. the cause of the subjective error is the human factor.

Errors in the interaction of changes over time and the input quantity are divided into static and dynamic errors.

Static error– this is an error that arises in the process of measuring a constant (not changing over time) quantity.

Dynamic error is an error, the numerical value of which is calculated as the difference between the error that occurs when measuring a non-constant (time-variable) quantity and the static error (the error in the value of the measured quantity at a certain point in time).

According to the nature of the dependence of the error on the influencing quantities, errors are divided into basic and additional.

Basic error– this is the error obtained under normal operating conditions of the measuring instrument (at normal values of the influencing quantities).

Additional error– this is an error that occurs when the values of influencing quantities do not correspond to their normal values, or if the influencing quantity exceeds the boundaries of the region of normal values.

Normal conditions – these are conditions in which all values of influencing quantities are normal or do not go beyond the boundaries of the normal range.

Working conditions– these are conditions in which the change in influencing quantities has a wider range (the influencing values do not go beyond the boundaries of the working range of values).

Working range of influencing quantities– this is the range of values in which the values of the additional error are normalized.

Based on the nature of the dependence of the error on the input value, errors are divided into additive and multiplicative.

Additive error– this is an error that arises due to the summation of numerical values and does not depend on the value of the measured quantity taken modulo (absolute).

Multiplicative bias is an error that changes with changes in the values of the quantity being measured.

It should be noted that the value of the absolute additive error is not related to the value of the measured quantity and the sensitivity of the measuring instrument. Absolute additive errors are constant over the entire measurement range.

The value of the absolute additive error determines the minimum value of the quantity that can be measured by the measuring instrument.

The values of multiplicative errors change in proportion to changes in the values of the measured quantity. The values of multiplicative errors are also proportional to the sensitivity of the measuring instrument. The multiplicative error arises due to the influence of influencing quantities on the parametric characteristics of the elements of the device.

Errors that may arise during the measurement process are classified according to the nature of their occurrence. Highlight:

1) systematic errors;

2) random errors.

Gross errors and errors may also occur during the measurement process.

Systematic error- This component the entire error of the measurement result, which does not change or changes naturally with repeated measurements of the same quantity. Usually, a systematic error is tried to be eliminated in possible ways (for example, by using measurement methods that reduce the likelihood of its occurrence), but if the systematic error cannot be eliminated, then it is calculated before the start of measurements and appropriate corrections are made to the measurement result. In the process of normalizing the systematic error, the boundaries of its permissible values are determined. Systematic error determines the accuracy of measurements of measuring instruments (metrological property).

Systematic errors in some cases can be determined experimentally. The measurement result can then be clarified by introducing a correction.

Methods for eliminating systematic errors are divided into four types:

1) elimination of the causes and sources of errors before the start of measurements;

2) elimination of errors in the process of already begun measurement by methods of substitution, compensation of errors by sign, opposition, symmetrical observations;

3) correction of measurement results by making an amendment (elimination of errors by calculations);

4) determination of the limits of systematic error in case it cannot be eliminated.

Elimination of causes and sources of errors before starting measurements. This method is the most optimal option, since its use simplifies the further course of measurements (there is no need to eliminate errors in the process of already started measurement or to make corrections to the result obtained).

To eliminate systematic errors in the process of already started measurement, various methods are used

Method of introducing amendments is based on knowledge of the systematic error and the current patterns of its change. When using this method, corrections are made to the measurement result obtained with systematic errors, equal in magnitude to these errors, but opposite in sign.

Substitution method consists in the fact that the measured quantity is replaced by a measure placed in the same conditions in which the object of measurement was located. The replacement method is used when measuring the following electrical parameters: resistance, capacitance and inductance.

Sign error compensation method consists in the fact that measurements are performed twice in such a way that an error of unknown magnitude is included in the measurement results with the opposite sign.

Method of opposition similar to the sign compensation method. This method consists of taking measurements twice so that the source of error in the first measurement has an opposite effect on the result of the second measurement.

Random error- this is a component of the error of the measurement result, changing randomly, irregularly when performing repeated measurements of the same quantity. The occurrence of a random error cannot be foreseen or predicted. Random error cannot be completely eliminated; it always distorts the final measurement results to some extent. But you can make the measurement result more accurate by taking repeated measurements. The cause of a random error may be, for example, a random change external factors, affecting the measurement process. A random error when carrying out repeated measurements with a sufficiently high degree of accuracy leads to scattering of the results.

Mistakes and gross errors– these are errors that far exceed the systematic and random errors expected under the given measurement conditions. Errors and gross errors may appear due to gross errors during the measurement process, technical malfunction means of measuring unexpected changes in external conditions.

Selection of measuring instruments

When choosing measuring instruments, first of all, the permissible error value for a given measurement, established in the relevant regulatory documents.

If the permissible error is not provided for in the relevant regulatory documents, the maximum permissible measurement error must be regulated in the technical documentation for the product.

When choosing measuring instruments, the following should also be taken into account:

1) permissible deviations;

2) measurement methods and control methods. The main criterion for choosing measuring instruments is the compliance of the measuring instruments with the requirements of measurement reliability, obtaining real (actual) values of the measured quantities with a given accuracy with minimal time and material costs.

To optimally select measuring instruments, you must have the following initial data:

1) the nominal value of the measured quantity;

2) the magnitude of the difference between the maximum and minimum values of the measured quantity, regulated in regulatory documentation;

3) information about the conditions for carrying out measurements.

If it is necessary to select a measuring system based on the criterion of accuracy, then its error must be calculated as the sum of the errors of all elements of the system (measures, measuring instruments, measuring transducers), in accordance with the law established for each system.

The preliminary selection of measuring instruments is made in accordance with the accuracy criterion, and the final selection of measuring instruments must take into account the following requirements:

1) to the working range of values of quantities that influence the measurement process;

2) to the dimensions of the measuring instrument;

3) to the mass of the measuring instrument;

4) to the design of the measuring instrument.

When choosing measuring instruments, it is necessary to take into account the preference of standardized measuring instruments.

19. Methods for determining and accounting for errors

Methods for determining and accounting for measurement errors are used to:

1) based on the measurement results, obtain the real (actual) value of the measured quantity;

2) determine the accuracy of the results obtained, i.e. the degree of their correspondence to the real (actual) value.

In the process of determining and accounting for errors, the following are assessed:

1) expected value;

2) standard deviation.

Point parameter estimate(mathematical expectation or standard deviation) is an estimate of a parameter that can be expressed in a single number. The point estimate is a function of experimental data and, therefore, must itself be a random variable distributed according to a law depending on the distribution law for the values of the initial random variable The law of distribution of point estimate values will also depend on the parameter being estimated and on the number of tests (experiments).

Point estimates are of the following types:

1) unbiased point estimate;

2) effective point estimate;

3) consistent point estimate.

Unbiased point estimate is an estimate of the error parameter, the mathematical expectation of which is equal to this parameter.

Effective point o

Metrology- the science of measurements, methods and means of ensuring their unity and methods of achieving the required accuracy. This definition is given by all Russian regulations, from GOST 16263-70 to the recently adopted recommendations of RMG 29-2013.

The International Dictionary of Metrology (VIM3) gives a broader definition of the term metrology as the science of measurement and its applications, which includes all theoretical and practical aspects of measurements, regardless of their uncertainty and field of use.

Reference. GOST 16263-70 “GSI. Metrology. Basic terms and definitions" was in force from 01/01/1971, replaced from 01/01/2001 by RMG 29-99 with the same name.
RMG 29-2013 “GSI. Metrology. Basic terms and definitions" - Recommendations for interstate standardization (introduced from 01/01/2015 instead of RMG 29-99). They have been updated and harmonized with the VIM3-2008 dictionary (3rd edition). Its full name is International Dictionary of Metrology: Basic and general concepts and related terms.

If we talk in simple language, metrology deals with the issues of measuring physical quantities that characterize all kinds of material objects, processes or phenomena. Her areas of interest include the development and practical application of measurement technologies, tools and equipment, as well as tools and methods for processing the received information. In addition, metrology provides legal regulation of the actions of official structures and individuals, one way or another related to the performance of measurements in their activities, studies and systematizes historical experience.

The word “metrology” itself comes from the Greek words “metron” - measure and “logos” - doctrine. At first, the doctrine developed as a science about measures and relationships between various quantities of measures (used in different countries), and was descriptive (empirical).

Measurements of new modern quantities, expansion of measurement ranges, increase in their accuracy, all this contributes to the creation latest technologies, standards and measuring instruments (MI), improving the ways of human comprehension of nature, knowledge of the quantitative characteristics of the surrounding world.

It has been established that currently there is a need to measure more than two thousand parameters and physical quantities, but so far, based on available tools and methods, about 800 quantities are measured. The development of new types of measurements remains actual problem and in our days. Metrology absorbs the latest scientific achievements and occupies a special place among the technical sciences, because for scientific and technological progress and their improvement, metrology must be ahead of other areas of science and technology.

Not a single technical specialist can do without knowledge of metrology (about 15% of social labor costs are spent on measurements). No industry can function without the use of its own measurement system. It is on the basis of measurements that technological processes are managed and the quality of manufactured products is monitored. According to experts in advanced industrial countries, measurements and related operations are estimated at 3 - 9% of the gross national product.

Goals and objectives of metrology

The goals of metrology as a science are to ensure the uniformity of measurements (UME); extraction of quantitative information about the properties of an object, the surrounding world, and processes with a given accuracy and reliability.

The goals of practical metrology are metrological support of production, i.e. establishment and application of scientific and organizational foundations, technical means, rules and regulations necessary for OI and the required accuracy of measurements.

Metrology tasks:

implementation public policy in OEI;
development of a new and improvement of the current regulatory framework for OI and metrological activities;
formation of units of quantities (MU), systems of units, their unification and recognition of legality;
development, improvement, maintenance, comparison and application of state primary standards of units of quantities;
improvement of methods (measurement principles) of transferring units of measurement from the standard to the measured object;
development of methods for transferring the sizes of units of quantities from primary and working measurement standards to working SI;
maintaining the Federal Information Fund for OEI and providing the documents and information contained therein;
provision of public services for OEI in accordance with the scope of accreditation;
establishment of rules and regulations for testing measuring instruments;
development, improvement, standardization of methods and measuring instruments, methods of determining and increasing their accuracy;
development of methods for assessing errors, the state of measuring instruments and control;
improvement of the general theory of measurements.

Reference. Previously, the tasks of metrology were formulated in GOST 16263-70.

In accordance with the assigned tasks, metrology is divided into on theoretical, applied, legislative and historical metrology.

Theoretical or fundamental metrology is engaged in the development of theory, problems of measuring quantities, their units, and measurement methods. Theoretical metrology deals with general problems that arise when performing measurements in a particular field of technology, humanities, and even at the junction of many, sometimes very diverse areas of knowledge. Theoretical metrologists can deal, for example, with the issues of measuring linear dimensions, volume and gravity in n-dimensional space, develop methods for instrumental assessment of the radiation intensity of cosmic bodies in relation to the conditions of interplanetary flights, or create completely new technologies that make it possible to increase the intensity of the process and the level of accuracy and its other parameters, improve the technical means involved in it, etc. One way or another, almost any undertaking in any activity begins with theory and only after such elaboration moves into the sphere of specific application.

Applied or practical metrology deals with issues of metrological support, practical use of developments in theoretical metrology, and implementation of the provisions of legal metrology. Its task is to adapt the general provisions and theoretical calculations of the previous section to a clearly defined, highly specialized industrial or scientific problem. So, if it is necessary to assess the strength of a motor shaft, calibrate a large number of bearing rollers, or provide, for example, comprehensive metrological control in the process of laboratory research, practitioners will select the appropriate technology from a large number of already known ones, process it, and possibly supplement it with application to these conditions, they will determine the necessary equipment and tools, the number and qualifications of personnel, and also analyze many other technical aspects of a particular process.

Legal metrology establishes binding legal and technical requirements on the use of standards, units of quantities, methods and measuring instruments aimed at ensuring the uniformity of measurements (UMU) and their required accuracy. This science was born at the intersection of technical and social knowledge and is designed to provide a unified approach to measurements carried out in all areas without exception. Legal metrology also directly borders on standardization, which ensures the compatibility of technologies, measuring instruments and other attributes of metrological support both at the domestic and international levels. The area of interest of legal metrology includes work with standards of measurement quantities, issues of verification of measuring instruments and equipment, and training of specialists, as well as many other issues. The main legal document regulating activities in this area is the Law of the Russian Federation N 102-FZ “On Ensuring the Uniformity of Measurements” dated June 26, 2008. The regulatory framework also includes a number of by-laws, provisions and technical regulations that specify the legislative requirements for certain areas and types of activities of metrology lawyers.

Historical metrology designed to study and systematize units and measurement systems used in the past, technological and instrumental support for monitoring the parameters of physical objects and processes, historical organizational legal aspects, statistics and much more. This section also explores the history and evolution of monetary units, tracing the relationship between their systems that were formed in the conditions of different societies and cultures. Historical metrology, in parallel with numismatics, studies monetary units because during the period of the birth of measurements as such, the elementary foundations of methods for assessing value and other parameters completely unrelated to monetary calculations largely repeated each other.

On the other hand, historical metrology is not a purely social branch of science, because often with its help, lost, but nevertheless relevant today measuring technologies are restored, development paths are tracked based on past experience and promising changes in this area are predicted, new ones are developed engineering solutions. Often, progressive methods for assessing any parameters are the development of already known ones, revised taking into account new capabilities. modern science and technology. Studying history is necessary to work with measurement standards in relation to their development and improvement, ensuring the compatibility of traditional and promising methods, as well as systematizing practical developments for the purpose of their use in the future.

Excerpts from the history of the development of metrology

For converting all kinds of measurements, counting time, etc. humanity needed to create a system of various measurements to determine volume, weight, length, time, etc. Therefore, metrology, as a field of practical activity, originated in ancient times.

The history of metrology is part of the history of the development of reason, productive forces, statehood and trade; it matured and improved along with them. Thus, already under the Grand Duke Svyatoslav Yaroslavovich, an “exemplary measure” began to be used in Rus' - the prince’s “golden belt”. Samples were kept in churches and monasteries. At Novgorod prince Vsevolod was ordered to review the measures annually, and punishment was applied for non-compliance - up to and including the death penalty.

The “Dvina Charter” of 1560 by Ivan the Terrible regulated the rules for storing and transferring the size of bulk substances - octopus. The first copies were in orders of the Moscow state, temples and churches. Work on the supervision of measures and their verification was carried out at that time under the supervision of the Pomernaya Hut and the Great Customs House.

Peter I allowed English measures (feet and inches) to be used in Russia. Tables of measures and relationships between Russian and foreign measures were developed. The use of measures in trade, in mining mines and factories, and at mints was controlled. The Admiralty Board took care of the correct use of measures of goniometric instruments and compasses.

In 1736, the Commission of Weights and Measures was formed. The original measure of length was the copper arshin and the wooden fathom. The pound bronze gilded weight is the first legalized state standard. Iron arshins were made by order of Tsarina Elizabeth Petrovna in 1858.

On May 8, 1790, France adopted the meter as a unit of length - one forty-millionth of the earth's meridian. (It was officially introduced in France by decree of December 10, 1799)

In Russia in 1835, standards of mass and length were approved - the platinum pound and the platinum fathom (7 English feet). 1841 is the year the Depot of Exemplary Weights and Measures was opened in Russia.

On May 20, 1875, the Meter Convention was signed by 17 states, including Russia. International and national prototypes of the kilogram and meter have been created. (Metrologist Day is celebrated on May 20).

Since 1892, the Depot of Exemplary Weights and Measures was headed by the famous Russian scientist D.I. Mendeleev. In metrology, the Mendeleev era is usually called the period from 1892 to 1918.

In 1893, on the basis of the Depot, the Main Chamber of Weights and Measures was established - a metrological institute, where tests and verification of various measuring instruments were carried out. (Mendeleev headed the Chamber until 1907). Currently it is the All-Russian Research Institute of Metrology named after D.I. Mendeleev.

Based on the Regulations on Weights and Measures of 1899, 10 more calibration tents were opened in different cities of Russia.

The 20th century, with its discoveries in mathematics and physics, turned M into a science of measurements. Nowadays, the state and formation of metrological support largely determines the level of industry, trade, science, medicine, defense and development of the state as a whole.

The metric system of weights and measures was introduced by the decree of the Council of People's Commissars of the RSFSR dated September 14, 1918 (it began the “normative stage” in Russian metrology). Accession to the International Metric Convention occurred in 1924, as well as the creation of a standardization committee in Russia.

1960 - The International System of Units was created. In the USSR, it began to be used in 1981 (GOST 8.417-81). 1973 - approved in the USSR State system ensuring the uniformity of measurements (GSI).

1993: the first law of the Russian Federation “On ensuring the uniformity of measurements”, the laws of the Russian Federation “On standardization” and “On certification of products and services” were adopted. Responsibility has been established for violation of legal norms and mandatory requirements of standards in the field of uniformity of measurements and metrological support.

Without measuring instruments and methods of their use scientific and technical progress would be impossible. IN modern world people cannot do without them even in everyday life. Therefore, such a vast layer of knowledge could not help but be systematized and formed as a complete one. The concept of “metrology” is used to define this direction. What are measuring instruments from the point of view scientific knowledge? One might say that this is a subject of research, but the activities of specialists in this field necessarily have a practical nature.

Metrology concept

IN general idea metrology is often considered as a body of scientific knowledge about means, methods and methods of measurement, which also includes the concept of their unity. To regulate the practical application of this knowledge, there is a federal agency for metrology, which technically manages property in the field of metrology.

As you can see, measurement occupies a central place in the concept of metrology. In this context, measurement means obtaining information about the subject of study - in particular information about properties and characteristics. A prerequisite is the experimental way of obtaining this knowledge using metrological tools. It should also be taken into account that metrology, standardization and certification are closely interrelated and only in combination can they provide practically valuable information. So, if metrology deals with development issues, then standardization establishes uniform forms and rules for the application of these same methods, as well as for recording the characteristics of objects in accordance with given standards. As for certification, its goal is to determine the compliance of the object under study with certain parameters established by the standards.

Goals and objectives of metrology

Metrology faces several important challenges, which are located in three areas - theoretical, legislative and practical. As scientific knowledge develops, goals from different directions are mutually complemented and adjusted, but in general, the tasks of metrology can be presented as follows:

Formation of systems of units and characteristics of measurement.
Develop general theoretical knowledge about measurements.
Standardization of measurement methods.
Approval of standards of measurement methods, verification measures and technical means.
Study of the system of measures in the context of historical perspective.

Unity of measurements

The basic level of standardization means that the results of measurements are reflected in an approved format. That is, the measurement characteristic is expressed in its accepted form. Moreover, this applies not only to certain measurement values, but also to errors that can be expressed taking into account probabilities. Metrological unity exists to make it possible to compare results that were carried out under different conditions. Moreover, in each case, the methods and means must remain the same.

If we consider the basic concepts of metrology from the point of view of the quality of results obtained, then the main one will be accuracy. In a sense, it is interrelated with the error, which distorts the readings. It is precisely in order to increase accuracy that serial measurements are used under various conditions, thanks to which it is possible to get a more complete picture of the subject of study. Preventive measures aimed at checking technical equipment, testing new methods, analyzing standards, etc. also play a significant role in improving the quality of measurements.

Principles and methods of metrology

For achievement High Quality The resulting measurements, metrology is based on several basic principles, including the following:

The Peltier principle, focused on determining the absorbed energy during the flow of ionizing radiation.
Josephson's principle, on the basis of which voltage measurements are made in an electrical circuit.
The Doppler principle, which provides velocity measurements.
The principle of gravity.

For these and other principles, a wide base of methods has been developed with the help of which practical research is carried out. It is important to consider that metrology is the science of measurements, which are supported by applied tools. But technical means, on the other hand, are based on specific theoretical principles and methods. Among the most common methods are the direct assessment method, measuring mass on a scale, substitution, comparison, etc.

Measuring instruments

One of the most important concepts in metrology is the means of measurement. As a rule, which reproduces or stores a certain physical quantity. During application, it examines the object, comparing the identified parameter with the reference one. Measuring instruments are a broad group of instruments that have many classifications. According to their design and principle of operation, for example, converters, devices, sensors, devices and mechanisms are distinguished.

A measuring setup is a relatively modern type of device used in metrology. What is this setting in practical use? Unlike the simplest tools, the installation is a machine that contains a whole range of functional components. Each of them may be responsible for one or more measures. An example is laser protractors. They are used by builders to determine a wide range of geometric parameters, as well as for calculations using formulas.

What is error?

Error also plays a significant role in the measurement process. In theory, it is considered as one of the basic concepts of metrology, in this case reflecting the deviation of the obtained value from the true one. This deviation may be random or systematic. In the design of measuring instruments, manufacturers usually include a certain amount of error in the list of characteristics. It is thanks to fixing the possible limits of deviations in the results that we can talk about the reliability of measurements.

But it is not only the error that determines possible deviations. Uncertainty is another characteristic that guides metrology in this regard. What is measurement uncertainty? Unlike error, it practically does not operate with exact or relatively accurate values. It only indicates doubt about a particular result, but, again, does not determine the intervals of deviations that could cause such an attitude towards the obtained value.

Types of metrology by area of application

Metrology in one form or another is involved in almost all spheres of human activity. In construction, the same measuring instruments are used to record deviations of structures along planes; in medicine, they are used on the basis of the most precise equipment; in mechanical engineering, specialists also use devices that allow them to determine characteristics in the smallest detail. Larger-scale specialized projects are carried out by the agency for technical regulation and metrology, which at the same time maintains a bank of standards, establishes regulations, carries out cataloging, etc. This body varying degrees covers all areas of metrological research, extending approved standards to them.

Conclusion

In metrology, there are previously established and unchanged standards, principles and methods of measurement. But there are also a number of its directions that cannot remain unchanged. Accuracy is one of the key characteristics that metrology provides. What is accuracy in the context of a measurement procedure? This is a quantity that largely depends on the technical means of measurement. And it is precisely in this area that metrology is developing dynamically, leaving behind outdated, ineffective tools. But this is just one of the most striking examples in which this area is regularly updated.

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 last century, thanks to progress 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.

Metrology, in its modern understanding, is the science of measurements, methods, means of ensuring their unity and methods of achieving the required accuracy.

Under uniformity of measurements understand the state of measurements in which their results are expressed in standardized units and measurement errors are known with a given probability. Unity of measurements is necessary so that the results of measurements taken at different places can be compared in different time, using different methods and measuring instruments.

The accuracy of measurements is characterized by the closeness of their results to the true value of the measured value. Since absolutely accurate instruments do not exist, the accuracy of instruments can only be discussed in terms of the theory of probability and mathematical statistics. The most important task of metrology is to improve standards, develop new methods of precise measurements, and ensure uniformity and the necessary accuracy of measurements.

Metrology includes the following sections:

1. Theoretical metrology, where general issues of measurement theory are considered.

2. Applied metrology studies issues of practical application of the results of theoretical research

3. Legal metrology considers a set of rules, norms and requirements regulated by government bodies to ensure uniformity of measurements and uniformity of measuring instruments.

Under measurement understand the process of obtaining quantitative information about the value of any physical quantity experimentally using measuring instruments.

Physical quantity- this is a property that is qualitatively common to many physical objects (systems, their states and processes occurring in them), but quantitatively individual for each object.

Unit of physical quantity is a physical quantity, the size of which is assigned a numerical value of 1. The size of a physical quantity is the quantitative content in a given object of a property corresponding to the concept of “physical quantity”.

For each physical quantity, a unit of measurement must be established. All physical quantities are interconnected by dependencies. Their totality can be considered as system of physical quantities. Moreover, if you select several physical quantities for basic, then other physical quantities can be expressed through them.

All units of measurement are divided into basic and derivatives(derived from the main ones). An expression reflecting the relationship of a physical quantity with the basic physical quantities of the system is called dimension of physical quantity.

Some concepts of dimensional theory

The operation of determining the dimension of a physical quantity x will be denoted by the corresponding capital letter

The theory of dimensions is based on the following statements (theorems)

1. The dimensions of the left and right parts must always match, i.e.

if there is some expression like

2. The algebra of dimensions is multicative, i.e. for dimensions, a multiplication operation is defined, and the operation of multiplying several quantities is equal to the product of their dimensions

3. The dimension of the quotient of dividing two quantities is equal to the ratio of their dimensions

4. The dimension of a quantity raised to a power is equal to the dimension of a quantity raised to the corresponding power

The operations of addition and subtraction of dimensions are not defined.

From the provisions of the theory of dimensionality it follows that the dimension of one physical quantity related by certain relationships with other physical quantities (i.e., for a quantity included in a system of physical quantities) can be expressed through the dimensions of these quantities.

The dimension of a physical quantity is its qualitative characteristics.