Metrological units. Metrology basic terms and definitions

The basic terms of metrology are established by state standards.

1. The basic concept of metrology - measurement. According to GOST 16263-70, measurement is finding the value of a physical quantity (PV) empirically with the help of special technical means.

The measurement result is the receipt of a quantity value in the process of measurement.

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

2. Measurement tool (SI) - a special technical means storing a unit of magnitude for comparing the measured value 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, repeatability, reproducibility and accuracy.

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

- Convergence - a property of measurements, reflecting the proximity to each other of the results of measurements performed under the same conditions, by the same SI, by the same operator.

- Reproducibility - the property of measurements, reflecting the proximity to each other of the results of measurements of the same quantity, carried out in different conditions - at different times, in different places, by different methods and means of measurement.

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

- Accuracy - property of measurements, reflecting the proximity of their results to the true value of the measured quantity.

This is the main property of measurements, since 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 - the state of measurements in which their results are expressed in legal units, and the errors are known with a given probability and do not go beyond the established limits.

Measures for real ensuring the uniformity of measurements in most countries of the world are established by laws and are included in the functions of legal metrology. In 1993, the RF Law "On ensuring the uniformity of measurements" was adopted.

Previously, legal norms were established by government decrees.

In comparison with the provisions of these resolutions, the Law established the following innovations:

In terminology - outdated concepts and terms have been replaced;

In the licensing of 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 revised;

Voluntary certification of measuring instruments, etc.

Preconditions for the adoption of the law:

The country's transition to a market economy;

As a result - the reorganization of the state metrological services;

This led to the disruption of the centralized management system for metrological activities and departmental services;

Problems arose during the state metrological supervision and control in connection with the emergence of various forms of ownership;

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:

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

Promotion of progress through the use of state measurement standards of units of quantities and the use of measurement results of guaranteed accuracy;

Creation of favorable conditions for the development of international relations;

Regulation of relations government agencies management of the Russian Federation with legal entities and individuals on the manufacture, release, operation, repair, sale and import of measuring instruments.

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

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

The cross-sectoral nature of the activity means the legal status of the State Metrological Service, similar to other control and supervisory bodies government controlled (Gosatomnadzor, Gosenergonadzor, etc.).

The subordinate nature of its activities means vertical subordination to one department - the 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",

- "Procedure for approving regulations on metrological services of federal executive bodies and legal entities",

- "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, + Old 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; normative base for this - 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 the issues of practical application of developments in theoretical metrology. She is in charge of all issues of metrological support.
Legislative - establishes mandatory technical and legal requirements for the use of units of a physical quantity, methods and measuring instruments.

Metrologist

Goals and objectives of metrology

creation of a general theory of measurements;
formation of units of physical quantities and systems of units;
development and standardization of methods and measuring instruments, methods for determining the accuracy of measurements, the foundations of 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 the development of a system of standards based on physical constants.

Also, metrology studies the development of a system of measures, monetary units and accounts in a historical perspective.

Axioms of metrology

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

Metrology terms and definitions

Unity of measurements - the state of measurements, characterized by the fact that their results are expressed in legalized units, the dimensions of which, within the established limits, are equal to the sizes of units reproduced by the primary standards, and the errors of the measurement results are known and do not exceed the established limits with a given probability.
Physical quantity - one of the properties of a physical object, qualitatively common to many physical objects, but quantitatively individual for each of them.
Measurement - a set of operations for the use of a technical means storing a unit of a physical quantity, ensuring finding the ratio of the measured quantity with its unit and obtaining the value of this quantity.
Measuring instrument - technical means intended for measurements and having normalized metrological characteristics that reproduce and (or) store a unit of quantity, the size of which is assumed to be unchanged within the specified error within a known time interval.
Verification - a set of operations performed in order 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.
Measurement error - the difference between the indication of the measuring instrument and the actual value of the measured physical quantity.
Measuring instrument accuracy - characteristic of the quality of the measuring instrument, reflecting the proximity of its error to zero.
License - this is a permit issued to the bodies of the state metrological service on the territory assigned to it to an individual or legal entity for the implementation of activities for the production and repair of measuring instruments.
Unit standard - technical means intended for transmission, storage and reproduction of a unit of magnitude.

History of metrology

Metrology traces its history back to ancient times and is even mentioned in the Bible. The earliest forms of metrology were to establish local authorities simple arbitrary standards, often based on simple practical measurements such as arm length. The earliest standards were introduced for quantities such as length, weight and time to facilitate commercial transactions as well as record human activity.

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

Historically important milestones in the development of metrology:

XVIII century - the establishment of the standard for the meter (the standard is kept in France, in the Museum of Weights and Measures; now it is more a historical exhibit than a scientific instrument);
1832 - creation of absolute systems of units by Karl Gauss;
1875 - signing of the international Metric Convention;
1960 - development and establishment of the International System of Units (SI);
XX century - metrological studies of individual countries are coordinated by International Metrological Organizations.

Milestones national history metrology:

joining the Metric Convention;
1893 - the creation of the Main Chamber of Weights and Measures by D. I. Mendeleev (modern name: "Mendeleev Scientific Research Institute of Metrology");

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

Formation and differences of metrology in the USSR (Russia) and abroad

The rapid development of science, technology and technology in the 20th century required the development of metrology as a science. In the USSR, metrology developed as a state discipline, since the need to improve the accuracy and reproducibility of measurements grew with the industrialization and growth of the military-industrial complex. Foreign metrology was also based on the requirements of practice, but these requirements came mainly from private companies. An indirect consequence of this approach was the state regulation of various concepts related to metrology, that is, GOST approval of everything that needs to be standardized. Abroad, this task was undertaken by non-governmental organizations, for example, ASTM.

Due to this difference in the metrology of the USSR and the post-Soviet republics state standards (standards) are recognized as dominant, in contrast to the competitive Western environment, where a private firm may not use an unwanted standard or device and agree with its partners about 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 to achieve the required accuracy.

MEASUREMENT

UNITY OF MEASUREMENTS

1. Physical quantities

PHYSICAL VALUE (FV)

REAL EF VALUE

PHYSICAL PARAMETER

Influencing fw

ROD FV

Qualitative certainty FV.

Part length and diameter-

FV UNIT

FV UNITS SYSTEM

DERIVATIVE UNIT

Unit of speed- meter / second.

OFFSYSTEM FV UNIT

allowed on par;.

temporarily admitted;

disused.

For instance:

- - units of time;

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

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

centner, etc.

MULTIPLE UNIT OF FV

LARGE FV

For example, 1μs \u003d 0.000 001s.

Basic terms and definitions metrology

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

MEASUREMENT

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

UNITY OF MEASUREMENTS

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

1. Physical quantities

PHYSICAL VALUE (FV)

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

TRUE VALUE OF PHYSICAL QUANTITY

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

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

REAL EF VALUE

The PV value found experimentally and is so close to the true value that it can replace it for the given measurement problem.

When verifying measuring instruments, for example, the actual value is the value of an exemplary standard or the indication of an exemplary measuring instrument.

PHYSICAL PARAMETER

PV, considered when measuring this PV as an auxiliary characteristic.

For example, the frequency when measuring AC voltage.

Influencing fw

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

ROD FV

Qualitative certainty FV.

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

FV UNIT

FV of a fixed size, which is conditionally assigned numerical value, equal to one, and used to quantify homogeneous PV.

There must be as many units as there is PV.

Distinguish between basic, derived, multiple, fractional, system and non-system units.

FV UNITS SYSTEM

A set of basic and derived units of physical quantities.

BASIC UNIT OF UNIT SYSTEM

The unit of the basic PV in this system of units.

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

ADDITIONAL UNIT OF UNIT SYSTEM

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

DERIVATIVE UNIT

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

Unit of speed- meter / second.

OFFSYSTEM FV UNIT

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 on par;.

allowed for use in special areas;

temporarily admitted;

disused.

For instance:

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

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

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

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

centner, etc.

MULTIPLE UNIT OF FV

The unit of PV is an integer number of times larger than the system or non-system unit.

For example, the unit of frequency is 1 MHz \u003d 1,000,000 Hz

LARGE FV

The unit of PV is an integer number of times less than the system or non-system unit.

For example, 1μs \u003d 0.000 001s.

Basic terms and definitions in metrology

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

Direct measurement- measurement, in which the desired value of the 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, functionally related to the desired quantity.

The true value of a physical quantity - the value of a physical quantity, which ideally characterizes the corresponding physical quantity in qualitative and quantitative terms.

The actual value of the physical quantity - the value of a physical quantity obtained experimentally and is so close to the true value that it can be used instead of it in the set measuring task.

Measured physical quantity - a physical quantity to be measured in accordance with the main purpose of the measuring task.

Influencing physical quantity - a physical quantity that affects the size of the measured quantity and (or) the measurement result.

Normal range of influence quantity - the range of values \u200b\u200bof the influencing quantity, within which the change in the measurement result under its influence can be neglected in accordance with the established accuracy standards.

Working range of influence quantity - the range of values \u200b\u200bof 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 - the difference in values \u200b\u200bcorresponding to two adjacent scale marks.

Measuring instrument indication range - the range of the instrument scale values, limited by the initial and final scale values.

Measuring range- the range of values \u200b\u200bof the quantity, within which the permissible error limits of the measuring instrument are normalized.

Measurement variation - difference in instrument readings at the same point of the measurement range with a smooth approach to this point from the side of smaller and larger values \u200b\u200bof the measured value.

Transmitter 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.

Measuring instrument sensitivity - 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 causing it

The absolute error of the measuring instrument - the difference between the indication of the measuring instrument and the true (actual) value of the measured quantity, expressed in units of the measured physical quantity.

Relative error of measuring instrument - the error of the measuring instrument, expressed by 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 the quantity (or standardizing value), constant over the entire measurement range or in a part of the range. The range of indications or the upper limit of measurements is often taken as the standardizing value. This error is usually expressed as a percentage.

Systematic error of a measuring instrument - the component of the error of the measuring instrument, taken as constant or regularly changing.

Random error of measuring instrument - the component of the error of the measuring instrument, which changes randomly.

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

Additional error of the measuring instrument - the component of the error of the measuring instrument that arises in addition to the basic error due to the deviation of any of the influencing quantities from its normal value or due to 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 instruments, at which it is still recognized as suitable for use.

Accuracy class of measuring instrument - a generalized characteristic of this type of measuring instruments, as a rule, reflecting the level of their accuracy, expressed by the limits of the permissible basic and additional errors, as well as other characteristics that affect the accuracy.

Measurement error - deviation of the measurement result from the true (valid) value of the measured value.

Miss (gross measurement error)- the error of the result of a separate measurement included in a series of measurements, which for these conditions differs sharply from the rest of the results of this series.

Measurement method error - component of the systematic measurement error caused by 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 to the reading of the measuring instrument is called the correction to the reading of the instrument.

Basic terms and definitions metrology

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

MEASUREMENT

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

UNITY OF MEASUREMENTS

ACCURACY OF MEASUREMENT RESULTS

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

1. Physical quantities

PHYSICAL VALUE (FV)

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

TRUE VALUE OF PHYSICAL QUANTITY

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

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

REAL EF VALUE

The PV value found experimentally and is so close to the true value that it can replace it for the given measurement problem.

When verifying measuring instruments, for example, the actual value is the value of an exemplary standard or the indication of an exemplary measuring instrument.

PHYSICAL PARAMETER

PV, considered when measuring this PV as an auxiliary characteristic.

For example, the frequency when measuring AC voltage.

Influencing fw

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

ROD FV

Qualitative certainty FV.

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

FV UNIT

FV of a fixed size, which is conventionally assigned a numerical value equal to one, and is used to quantify homogeneous FV.

There must be as many units as there is PV.

Distinguish between basic, derived, multiple, fractional, system and non-system units.

FV UNITS SYSTEM

A set of basic and derived units of physical quantities.

BASIC UNIT OF UNIT SYSTEM

The unit of the basic PV in this system of units.

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

ADDITIONAL UNIT OF UNIT SYSTEM

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

DERIVATIVE UNIT

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

Unit of speed- meter / second.

OFFSYSTEM FV UNIT

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 on par;.

allowed for use in special areas;

temporarily admitted;

disused.

For instance:

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

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

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

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

centner, etc.

MULTIPLE UNIT OF FV

The unit of PV is an integer number of times larger than the system or non-system unit.

For example, the unit of frequency is 1 MHz \u003d 1,000,000 Hz

LARGE FV

The unit of PV is an integer number of times less than the system or non-system unit.

For example, 1μs \u003d 0.000 001s.

Metrology Basic terms and definitions

UDC 389.6 (038): 006.354 Group T80

STATE SYSTEM FOR ENSURING 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

Foreword

1 DEVELOPED by the All-Russian Scientific Research Institute of Metrology. D.I. Mendeleeva of the State Standard of Russia

SUBMITTED 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 dated May 26-28, 1999)

State name	Name of the national standardization body
The Republic of Azerbaijan	Azgosstandart
Republic of Armenia	Armgosstandart
Republic of Belarus	State Standard of Belarus
	Gruzstandart
The Republic of Kazakhstan	Gosstandart of the Republic of Kazakhstan
The Republic of Moldova	Moldovastandart
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 the Decree of the State Committee of the Russian Federation for Standardization and Metrology of May 17, 2000 No. 139-st, the interstate Recommendations RMG 29-99 were put into effect directly as the Recommendations on Metrology of the Russian Federation from January 1, 2001.

4 REPLACE GOST 16263-70

5 REDISSION. September 2003

Amendment No. 1 was introduced, adopted by the Interstate Council for Standardization, Metrology and Certification (Protocol No. 24 dated 05.12.2003) (IMS No. 1 2005)

Introduction

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

For each concept, one term is established, which has a terminological entry 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 interpretation.

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

In the alphabetical index of terms in Russian, these terms are listed in alphabetical order with the number of the terminological entry (for example, "value 3.1"). Moreover, for the terms given in the notes, after the article number, the letter "p" is indicated (for example, legalized units 4.1 p).

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

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

For the concept of "additional unit" the definition is not given, since the term fully discloses its content.

Without measuring instruments and methods of their application, scientific and technological progress would be impossible. In the modern world, people cannot do without them even in everyday life. Therefore, such an extensive layer of knowledge could not be systematized and formed as a full-fledged one. The concept of “metrology” is used to define this direction. What are measuring instruments in terms of scientific knowledge? It can be said that this is a subject of research, but the activities of specialists in this area necessarily have a practical character.

Metrology concept

In general terms, 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 federal agency in Metrology, which technically manages assets in the field of metrology.

As you can see, measurement is central to the concept of metrology. In this context, measurement means obtaining information about the subject of research - in particular, information about properties and characteristics. A prerequisite is precisely the experimental way of obtaining this knowledge using metrological tools. It should also be borne in mind that metrology, standardization and certification are closely interrelated and only in a complex can provide practically valuable information. So, if metrology deals with development issues, then standardization establishes uniform forms and rules for the application of the same methods, as well as for recording the characteristics of objects in accordance with specified standards. With regard to certification, it aims to determine the compliance of the investigated object with one or another of the parameters laid down by the standards.

Goals and objectives of metrology

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

Formation of systems of units and measurement characteristics.
Development of 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 a historical perspective.

Unity of measurements

The basic level of standardization means that the results of the measurements made are reflected in an approved format. That is, the measurement characteristic is expressed in the 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 for the possibility of comparing the results that were carried out in 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 obtaining results, then the main one will be accuracy. In a sense, it is associated with an error that distorts the readings. It is in order to improve accuracy that serial measurements are used under various conditions, thanks to which you can get a more complete picture of the subject of study. Preventive measures aimed at checking technical means, testing new methods, analyzing standards, etc. also play a significant role in improving the quality of measurements.

Principles and methods of metrology

To achieve high quality measurements, metrology relies on several basic principles, including the following:

The Peltier principle, focused on determining the absorbed energy in the course of the flow of ionizing radiation.
The Josephson principle, on the basis of which voltage measurements in an electrical circuit are made.
Doppler principle that provides speed measurement.
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 that 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, one can single out the method of direct assessment, measurement of mass on a balance, substitution, comparison, etc.

Measuring instruments

One of the most important concepts in metrology is a measuring instrument. As a rule, which reproduces or stores a certain physical quantity. In the process of application, it examines the object, comparing the detected parameter with the reference one. Measuring instruments are an extensive group of instruments with many classifications. According to the design and principle of operation, for example, converters, devices, sensors, devices and mechanisms are distinguished.

A measuring device is a relatively modern type of device used by metrology. What is this setting in practice? Unlike the simplest tools, the installation is a machine with a whole range of functional components. Each of them can 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 to calculate using formulas.

What is margin of error?

The error also takes a significant place 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 can be accidental or systematic. In the development of measuring instruments, manufacturers usually include a certain amount of error in the specification list. It is thanks to the fixation of the possible limits of deviations in the results that we can talk about the reliability of measurements.

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

Varieties of metrology by application

Metrology in one form or another is involved in almost all spheres of human activity. In construction, the same measuring devices are used to fix deviations of structures along planes, in medicine they are used on the basis of the most accurate equipment, in mechanical engineering, specialists also use devices that allow one to determine the characteristics with the smallest details. Larger 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, to varying degrees, covers all areas of metrological research, extending approved standards to them.

Conclusion

In metrology, there are previously established and unchanging standards, principles and measurement methods. 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 value that largely depends on the technical means of measurement. And it is in this area that metrology is developing dynamically, leaving behind obsolete, ineffective instruments. But this is just one of the most striking exampleswhich regularly update this area.

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

The International Vocabulary of Metrology (VIM3) gives a broader definition of the term "metrology" as the science of measurement and its application, which includes all theoretical and practical aspects of measurement, 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 simple language, metrology deals with the measurement of physical quantities that characterize all kinds of material objects, processes or phenomena. Her area of \u200b\u200binterest includes the development and practical application of measuring technologies, tools and equipment, as well as tools and methods for processing the information received. 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 the historical experience.

The very word "metrology" comes from the Greek words "metron" - measure and "logos" - doctrine. At first, the doctrine developed in this way, as the science of measures and relationships between different values \u200b\u200bof measures (used in different countries), and was descriptive (empirical).

Measuring new modern quantities, expanding the ranges of measurements, increasing their accuracy, all this contributes to the creation of the latest technologies, standards and measuring instruments (SI), the improvement of the ways of comprehending nature by man, the knowledge of the quantitative characteristics of the surrounding world.

It has been established that at present there is a need to measure more than two thousand parameters and physical quantities, but so far, on the basis of the available means and methods, measurements are being made of about 800 quantities. Mastering new types of measurements remains an urgent problem today. Metrology absorbs the latest scientific achievements and occupies a special place among 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 technician can do without knowledge of metrology (about 15% of social labor costs are spent on measurements). No industry can function without its own measurement system. It is on the basis of measurements that technological processes are controlled, quality control of manufactured products. 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 (OEI); extraction of quantitative information about the properties of an object, the surrounding world, about 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 required for the OIE and the required accuracy of measurements.

Metrology objectives:

realization public policy at OEI;
development of a new and improvement of the current regulatory framework of the OEI and metrological activities;
formation of units of quantities (EB), systems of units, their unification and recognition of legality;
development, improvement, maintenance, comparison and application of state primary measurement 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, regulations for carrying out verification of measuring instruments;
development, improvement, standardization of methods and measuring instruments, methods for determining and increasing their accuracy;
development of methods for assessing errors, state of measurement and control;
improvement of the general theory of measurements.

Reference. Earlier metrology tasks were formulated in GOST 16263-70.

In accordance with the tasks set, metrology is subdivided on theoretical, applied, legal and historical metrology.

Theoretical or fundamental metrology is engaged in the development of theory, problems of measurement of quantities, their units, measurement methods. Theoretical metrology deals with common problems that arise when performing measurements in a particular field of technology, humanities, and even at the junction of many, sometimes the most diverse areas of knowledge. Metrologists-theorists 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, 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 a theory and only after such elaboration does it move into the sphere of concrete application.

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

Legal metrology establishes mandatory legal and technical requirements for the use of standards, units of quantities, methods and measuring instruments aimed at ensuring the uniformity of measurements (OUU) 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 performed 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 \u200b\u200binterests of legal metrology includes work with measurement standards, and 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 legal requirements for certain areas and types of activities of metrology lawyers.

Historical metrology is designed to study and systematize the units and systems of measurement used in the past, technological and instrumental support for monitoring the parameters of physical objects and processes, historical organizational and legal aspects, statistics and much more. This section also examines the history and evolution of monetary units, traces the relationship between their systems, formed in the context of different societies and cultures. Historical metrology, in parallel with numismatics, studies monetary units already because in the period of the inception of measurements as such, the elementary foundations of methods for assessing value and other parameters that are 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, the development paths are tracked in the 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 the new possibilities of modern science and technology. The study of history is necessary to work with measuring standards in relation to their development and improvement, to ensure the compatibility of traditional and promising methods, as well as to systematize practical developments in order to use them in the future.

Excerpts from the history of the development of metrology

To convert all kinds of measurements, timing, etc. mankind 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 antiquity.

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. So already under the Grand Duke Svyatoslav Yaroslavovich in Russia, the "exemplary measure" - the "golden belt" of the prince began to be applied. The samples were kept in churches and monasteries. Under the Novgorod prince Vsevolod, it was ordered to compare measures annually, for failure to comply, punishment was applied - up to the death penalty.

The "Dvinskaya gramota" of 1560 by Ivan the Terrible regulated the rules for storing and transferring the size of loose substances - the octopus. The first copies were in the orders of the Moscow State, temples and churches. The work on the supervision of the measures and their verification was carried out at that time under the supervision of the Pomerna Hut and the Great Customs.

Peter I allowed English measures (feet and inches) to be circulated 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, in mints was controlled. The Admiralty Collegium took care of the correct use of measures, goniometric devices, compasses.

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

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

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

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

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

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

On the basis of the Regulations on Weights and Measures of 1899, 10 more test 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. Today, 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 measures and weights was introduced by the decree of the Council of People's Commissars of the RSFSR dated 09/14/1918 (from which the "normative stage" in Russian metrology began). Joining the International Metric Convention took place in 1924, as well as the creation of a committee for standardization 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. Liability was established for violation of legal norms and mandatory requirements of standards in the field of measurement uniformity and metrological support.

The basic terms of metrology are established by state standards.

1. The basic concept of metrology — measurement. According to GOST 16263-70, measurement is finding the value of a physical quantity (PV) experimentally using special technical means.

The measurement result is the receipt of a quantity value in the process of measurement.

2. Measurement tool (SI) - a special technical means storing a unit of magnitude for comparing the measured value 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, repeatability, reproducibility and accuracy.

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

- Convergence - the property of measurements, reflecting the proximity to each other of the results of measurements performed under the same conditions, by the same SI, by the same operator.

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

- Accuracy - property of measurements, reflecting the proximity of their results to the true value of the measured quantity.

This is the main property of measurements, since 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.

Previously, legal norms were established by government decrees.

In comparison with the provisions of these resolutions, the Law established the following innovations:

In terminology - outdated concepts and terms have been replaced;

In the licensing of 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 revised;

Voluntary certification of measuring instruments, etc.

Preconditions for the adoption of the law:

As a result - the reorganization of the state metrological services;

This led to the disruption of the centralized management system for metrological activities and departmental services;

Problems arose during the state metrological supervision and control in connection with the emergence of various forms of ownership;

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:

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

Promotion of progress through the use of state measurement standards of units of quantities and the use of measurement results of guaranteed accuracy;

Creation of favorable conditions for the development of international relations;

Regulation of relations between the state governing bodies of the Russian Federation with legal entities and individuals on the issues of manufacture, release, operation, repair, sale and import of measuring instruments.

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

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

The inter-sectoral nature of the activity means the legal status of the State Metrological Service, similar to other control and supervisory bodies of state administration (Gosatomnadzor, Gosenergonadzor, etc.).

The subordinate nature of its activities means vertical subordination to one department - the Gosstandart of Russia, within 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",

- "Procedure for approving regulations on metrological services of federal executive bodies and legal entities",

- "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.

In this article, we will find out what metrology is. It is quite difficult to imagine scientific and technological progress without methods and measuring instruments. Even in many everyday matters, we cannot do without them. For this reason, such a large-scale and all-encompassing volume of knowledge could not remain without systematization and separation into a separate area of \u200b\u200bscience. It is this scientific direction that is called metrology. She explains the various measuring instruments from a scientific point of view. This is the subject of metrology research. However, the activities of metrology specialists also include a practical component.

What is metrology

The International Dictionary of Basic and General Terms in Metrology defines this concept as a science of measurements. Metrology, as well as any type of measurement, plays a significant role in almost all areas of human activity. They are applied everywhere, including production control, environmental quality, human safety and health, and the assessment of materials, food products, fair trade and consumer protection products. What lies at the heart of metrology?

The term “metrological infrastructure” is often used. It applies to the measurement capacity of a region or country as a whole and involves the operation of verification and calibration services, laboratories and metrological institutes, as well as the management and organization of the metrology system.

Basic concepts

The concept of "metrology" is most often used in a generalized meaning, implying not only theoretical, but also practical aspects of the measuring system. If you need to specify the scope, the following concepts are usually used.

General metrology

What is this type of metrology? It deals with issues that are common to all areas of metrological measurement. General metrology deals with practical and theoretical issues that affect measurement units, namely the structure of the system of units, as well as the conversion of measurement units in formulas. She also deals with measurement errors, measurement instruments and metrological properties. Quite often, general metrology is also called scientific. General metrology covers various fields, for example:

Industrial metrology

What is industrial metrology? This area of \u200b\u200bscience deals with production measurement as well as quality control. The main challenges faced by industrial or technical metrology are calibration intervals and procedures, control of measurement equipment, verification of a measurement process, etc. Quite often, this concept is used in the description of metrological activities in the industrial field.

Legal metrology

This term is included in the list of mandatory requirements from a technical point of view. Organizations related to the field of legal metrology are engaged in checking the implementation of these requirements in order to identify the reliability and correctness of the measurement procedures. This applies to public areas such as health care, trade, security and environment... The areas covered by legal metrology depend on the respective regulations for each individual country.

Let's consider the basics of metrology in more detail below.

The basics

The subject of metrology is the derivation of information in certain units of measurement, containing information about the properties of the object under consideration, as well as processes, according to the established reliability and accuracy.

Metrology means are understood as a set of measuring instruments and generally accepted standards that allow their rational use. Standardization and metrology are closely related.

Objects

Metrology objects include:

Any quantity that is being measured.
Physical unit.
Measurement.
Measuring error.
Measurement method.
The means by which the measurement is made.

Significance criteria

There are also certain criteria that determine the social significance of metrological work. These include:

Providing reliable and maximally objective information about the measurements.
Protecting the public from incorrect measurement results in order to ensure safety.

Objectives

The main goals of technical regulation and metrology are:

Improving the quality of products of domestic manufacturers and increasing its competitiveness. This applies to increasing production efficiency, automation and mechanization of the product creation process.
Adaptation of the Russian industry to the general requirements of the market and overcoming technical barriers in the field of trade.
Saving resources of various types.
Raising the effectiveness of cooperation in the international market.
Keeping records of manufactured products and resources of the material plan.

Tasks

Metrology tasks include:

Development of measurement theory.
Development of new tools and methods for conducting measurements.
Providing uniform measurement rules.
Improving the quality of equipment used for measuring work.
Certification of equipment for measurements according to current regulations.
Improvement of documents regulating the main issues of metrology.
Professional development of personnel who provide the measurement process.

Kinds

Measurements are classified according to a number of factors, namely, by the method of obtaining information, by the nature of changes, by the amount of information to be measured, in relation to normal indicators. There are such types of metrology.

According to the way in which information is obtained, direct and indirect, as well as joint and aggregate measurements are distinguished.

What are the means of metrology?

Direct and indirect measurements

Straight lines mean a physical comparison of measure and value. So, for example, when measuring the length of an object using a ruler, the quantitative expression of the length value is compared with the object of measure.

Indirect measurements imply the setting of the desired value of the quantity as a result of direct measurements of indicators related in a certain way to the quantity being verified. For example, when measuring the current strength with an ammeter, and with a voltmeter - voltage, taking into account the relationship of the functional nature of all quantities, it is possible to calculate the power of the entire electrical circuit.

Aggregate and shared measurements

Aggregate measurements involve solving equations in a system obtained as a result of measurements of several quantities of the same type simultaneously. The required value is calculated by solving the given system of equations.

Joint measurements is the definition of two or more heterogeneous physical quantities in order to calculate the relationship between them. The last two types of measurements are quite often used in the field of electrical engineering to determine different types parameters.

By the nature of changes in the quantity in the process of carrying out measuring procedures, dynamic, statistical and static measurements are distinguished.

Statistical

Measurements are called statistical measurements that are associated with the identification of signs of random processes, the level of noise, sound signals, etc. In contrast, static changes are characterized by a constant measured value.

Dynamic measurements include measurements of quantities that tend to change in the course of metrological work. Dynamic and static measurements are rarely found in practice in their ideal form.

Multiple and single

According to the amount of information, measurements are subdivided into multiple and single. A single measurement means one measurement of one quantity. Thus, the number of measurements is fully correlated with the quantities that are measured. The use of this type of measurement is associated with significant calculation errors, therefore, it involves the derivation of the arithmetic mean after several metrological procedures.

Multiple measurements are those measurements that are characterized by an excess of the number of metrological operations over the measured values. The main advantage of this type of measurement is the insignificant effect of random factors on the error.

Absolute and relative

In relation to the main metrological units, absolute and relative measurements are distinguished.

Absolute measurements involve the use of one or more basic quantities in conjunction with a constant constant. Relative ones are based on the ratio of a metrological quantity to a homogeneous quantity used as a unit.

Measurement scale

Concepts such as measurement scale, principles and methods are directly related to metrology.

A measurement scale is understood as a systematized set of values \u200b\u200bof a quantity in its physical expression. It is convenient to consider the concept of a measurement scale using the example of temperature scales.

The ice melting temperature is the starting point, and the reference point is the temperature at which the water boils. One temperature unit, that is, degrees Celsius, is one hundredth of the above-described range. There is also a temperature scale in Fahrenheit, the starting point of which is the melting temperature of a mixture of ice with ammonia, and normal body temperature is taken as the reference point. One Fahrenheit unit is the ninety-sixth of the interval. On this scale, ice melts at 32 degrees, and water boils at 212. Thus, it turns out that the interval is 100 degrees Celsius, and 180 Fahrenheit.

Other types of scales are also known in the metrology system, for example, names, orders, intervals, ratios, etc.

The naming scale implies a qualitative but not a quantitative unit. This type of scale does not have a starting point, reference point, and metrological units. An example of such a scale is a color atlas. It is used to visually correlate the painted object with the reference samples included in the atlas. Since there can be a great variety of shades, the comparison should be made by an experienced specialist who has rich practical experience in this area, as well as special visual abilities.

The scale of the order is characterized by the value of the measurement value, expressed in points. These can be scales of earthquakes, hardness of bodies, wind strength, etc.

The scale of differences or intervals has relative zero values. The intervals on this scale are determined by agreement. This group includes length and time scales.

The ratio scale has a specific zero value, and the metrological unit is determined by agreement. The mass scale, for example, can be graduated in different ways, taking into account the required weighing accuracy. Analytical and household scales differ significantly from each other.

Conclusion

Thus, metrology takes part in all practical and theoretical areas of human activity. In the construction field, measurements are used to determine the deviations of a structure in certain planes. In the medical field, precision equipment allows for diagnostic procedures, the same applies to mechanical engineering, where specialists use devices that make it possible to make calculations with maximum accuracy.

There are also special metrology centers that carry out technical regulation and carry out large-scale projects, as well as establish regulations and carry out systematization. Such agencies extend their influence to all types of metrological research by applying established standards to them. Despite the accuracy of many indicators used in metrology, this science, like all others, continues to move forward and undergoes certain changes and additions.