Means intended for measuring quantities. Measuring instruments

In this article we will try to compactly analyze a whole set of topics: metrology, related standardization, Russian state metrological centers, as well as measuring instruments - their characteristics, types, classification and use. Let's start with the most common introductory topic - the science called metrology.

Metrology: definitions, goals, laws

Interconnected concepts. Metrology (ancient Greek μέτρον + λόγος - “measure” + “science”) is the science of weights and measures, namely measurement, its methods and means that help ensure the unity and accuracy of measurements.

The fundamentals of metrology involve the following goals and objectives:

• development of a unified measurement theory;
• row formation;
• development and subsequent standardization of tools and their accuracy, the desire for uniformity and unification;
• development of clear systems of standards, measurement samples, the basis of which are physical constants;
• study of the system of weights and measures in historical retrospect.

There are three basic laws of metrology:

1. Any measurement is a comparison.
2. It is impossible to obtain any measurement without a priori data.
3. The totals of any measurement without rounding values ​​are just a random variable.

Sections of metrology

Science is divided into several components:

• Theoretical. The fundamentals of metrology are based on theory. This section studies the most general problems of quantitative measurements, and also directly develops theoretical tenets.
• Legislative. Social science that defines mandatory legal and technical conditions for the use of units, methods and means of measurement.
• Applied. An experimental, practical section of metrology, introducing the development of the theoretical component into practice, as well as dealing with metrological support.
• Historical. Studies the units of measurement of the past, their progression over time, determines their names, as well as relationships with the standards of weights and measures of our time.
• Specialized areas. This includes “special” metrology - medical, chemical, aviation, biological (biometrics).

Standardization in metrology

Metrology and standardization are closely related. Standardization in this aspect is the general and specific rules of metrological support accompanying the production process. The objects of the discipline will be everything related to the product: regulatory documents with quality requirements, tolerance standards, as well as methods for achieving the standard result. At the same time, the developed standards can be applied not only at a specific enterprise, but also become generally useful.

The goals of standardization in metrology are as follows:

• Determining the main characteristics of high-quality reference products, the first step is to standardize components and source material.
• Development of certain criteria for the quality of the resulting product, while determining the means of metrological control.
• Striving for uniformity of products.
• Creation of a system of standards, ensuring the uniformity of all measurements at the enterprise.

Metrology and standardization operate on two main documents:

• A standard is a regulatory and technological act with certain norms, rules and requirements for production and the finished product. The current standard is the one approved by the authorized organization.
• TU (technical conditions) - a number of rules, norms and requirements for a specific type of product.

Scale of standardization in metrology:

• International. International centers of standardization and metrology are created by several states united by trade, common scientific developments, building joint defense, etc.
• State. Standardization in metrology, carried out by government authorities, who also build prospects for its development.
• National. Again, on a state scale, but without direct intervention from government agencies.

The main Russian center for standardization and metrology is the GSS (state standardization system). This complex combines all the developed requirements into one whole, helps to standardize the production and products of all domestic factories and combines.

State centers of metrology and certification

According to the Federal Law "On Ensuring the Uniformity of Measurements" at the state level, Gosstandart of the Russian Federation manages activities to ensure the unification of measurements. The State Metrological Service is also under its jurisdiction. It includes the following components:

• The departments of the central office of the State Standard of the Russian Federation are responsible for planning, management and control over the uniformity of measurements at the state intersectoral level.
• SSMC (state scientific metrological centers) are responsible for the development, storage and application of reference standards, as well as for the preparation of regulatory documentation that ensures the uniformity of measurements.
• HMS divisions on the scale of constituent entities of the Russian Federation - implementation of metrological control in specific territories.

Standard centers in the Russian Federation

The main center of state metrology is considered to be VNIIMS - the All-Russian Scientific Research Institute of Metrological Service. He carries out scientific and methodological management of all metrological services, coordinates their activities, and also develops a wide variety of (economic, organizational, scientific) foundations for metrological support.

In addition to VNIIMS, important standards centers in the Russian Federation will also be:

• VNIIM. Almost all standards of the World System of Weights and Measures were created and stored here, excluding samples of units of frequency and time. The institute contains more than 50% of all Russian state standards.
• VNIIFTRI. In addition to the time standard, this institute contains a sample of magnetic, radio engineering quantities, units of frequency, hardness, pressure, ionizing radiation, low temperatures, etc.
• VNIIOFI. Measurements of various laser parameters, medical indicators, spectrometry, optical quantities, etc.
• SNIIM. Standards of electrical, magnetic, radio engineering quantities, etc.

Activities of metrology centers

The main vector of activity of the State Migration Service is to ensure the unity of all measurements in the state. She is also responsible for metrological support of measurements in Russia, state control in the field of metrology. The areas of work of the HMS are also:

• creation of standards, state and secondary;
• formation of systems for broadcasting or transferring parameters of FB units to working SI;
• state supervision over the manufacture/use/condition/repair of measurement systems;
• metrological examination of various products;
• methodological support of lower-level metrological services.

Functions of Rosstandart

Rosstandart and metrology is the performance by this institution of the following functions:

• Coordination of work to ensure uniformity of measurements.
• Development of rules for the creation, storage, approval and operation of measurement standards.
• Metrological state supervision.
• Management of the State Migration Service and other services responsible for the uniformity of measurements.
• Approval of standards and regulations ensuring the uniformity of measurements.
• Recognition of technical devices as means of measurement.
• Development and approval of measurement methods.
• Accreditation of centers testing SI.
• Approval of SI types.
• Maintaining the State Register of SI.
• Approval of lists of measuring instruments subject to verification.
• Development of a licensing process for individuals and legal entities manufacturing, repairing, selling or renting measuring instruments.
• Planning and organization of various metrological activities, etc.

SI is...

Let's move on to metrology and measurements. - by which measurements are taken. It is characterized by the fact that it reproduces or stores a unit of measurement of any physical quantity.

Federal Law of the Russian Federation No. 102 defines SI as a means, one of the purposes of which is measurement. Only the Federal Agency for Technical Regulation and Metrology can classify any device as a measuring instrument in our country.

SI classification

Here are the most common classifications of measuring instruments in metrology and measurements:

• By measuring parameters to determine:
  • pressure;
  • temperature;
  • quantities;
  • level;
  • solution concentration, etc.
• According to the significance of what is being measured:
  • fixed assets;
  • auxiliary means.
• According to SI standardization:
  • standardized;
  • not related to standardized ones.
• According to the position in the verification diagram:
  • standards;
  • SI workers.
• By automation level:
  • manual;
  • automated;
  • automatic.
• By technical purpose:
  • a measure of physical quantity - SI, which reproduces or stores the value of one/several sizes;
  • measuring instrument - SI, with which you can find out the value of what is being measured in a certain range;
  • - SI, which converts one measured quantity into another;
  • measuring installation - a complex that combines several measuring transducers, instruments or measures, which is located in a certain location;
  • measuring system - a complex that combines several measures, instruments, installations and converters, capable of taking measurements in different parts of the object;
  • measuring and computing complex - a system that combines several measuring instruments and computers, designed to solve one or more complex measurement problems.

Measurements: types and methods

Measurement is the determination of the value of the desired quantity experimentally using SI. There are two main methods - direct assessment and comparison with a measure. The latter is further subdivided into differential, zero, coincidence and opposition methods. Regarding the SI used, a distinction is made between organoleptic, heuristic, expert and instrumental methods.

Speaking about metrology and measurements, let us present a classification of the types of the latter:

• According to the accuracy characteristics: equal and unequal. Or maximum accuracy, control, verification and technical.
• By method of obtaining data: contact and non-contact.
• By number of measurements: single and multiple.
• By type of change in the measured value: static and dynamic.
• Purpose: metrological and technical.
• According to the type of presentation of the result: relative and absolute.
• By methods of obtaining effective data: direct, indirect, cumulative and joint.

Areas of application of SI

In conclusion of the topic “Metrology, measurements, measuring instruments” we will outline the areas of application of SI dictated by Federal Law No. 102:

• environmental protection;
• occupational Safety and Health;
• state control;
• areas of activity in the defense complex;
• hydrometeorology;
• financial, tax, customs, banking operations;
• sport;
• road safety;
• veterinary medicine;
• judicial system;
• telecommunications, mail;
• conformity assessment;
• medicine;
• production control;
• geography, geodesy;
• packaging of products;
• trade;
• field of nuclear energy.

Standards and metrology are of utmost importance both for scientific and experimental activities, and for all spheres of social life. If it is difficult to imagine production without standardization in metrology, then measuring instruments have even more so become an integral part of human life.

1 Measuring instrumentsAndtypes of measuring instruments Measurement is finding the value of a physical quantity experimentally using special technical means 2. Measuring instruments Measuring instruments are technical means that have standardized metrological characteristics. In this case, the value of a physical quantity, counted by the reading device of the measuring instrument, strictly corresponds to a certain number of physical units accepted as units of measurement. Measuring instruments include:- measure, - measuring instruments, - measuring transducers, - measuring systems, - installations, complexes. Measure is a measuring instrument designed to reproduce a physical quantity of a given size. Measures can be single-valued or multi-valued. Unambiguous measures include resistance coils, inductance coils, normal elements, etc.; to multi-valued - resistance stores, variable capacitors, voltage and current calibrators, etc. Measuring device- a measuring instrument designed to provide quantitative information about the measured value in a form accessible to perception. According to the method of counting the values ​​of the measured quantity, measuring instruments are divided into analog and digital. In analog measuring instruments, the value of the measured quantity is determined directly on a scale with an arrow or other indicators. In digital measuring instruments, the value of the measured quantity is determined by the digital indicator of the device. Measuring instruments are divided into indicating and recording. Indicating measuring instruments are designed to read the measurement result in analogue or digital form, while recording instruments are designed to register the measurement result. Transducer- a measuring instrument designed to generate a signal of measuring information in a form convenient for transmission, further conversion, processing and storage, but not amenable to direct perception. Measuring converters include voltage dividers, amplifiers, instrument transformers, etc. 3. Types of measuring instruments According to their metrological purpose, measuring instruments are divided into: - standards, - exemplary, - working. Working measuring instruments are used for measurements not related to the transfer of unit sizes. In turn, working measuring instruments can be divided into: - technical - control - laboratory Technical measuring instruments Designed for use in industrial environments. Therefore, they must be inexpensive and reliable in operation. The readings of such devices are not corrected for measurement error. Control measuring instruments- serve to monitor the serviceability of industrial measuring instruments at their installation site. Laboratory measuring instruments- used for precise measurements in laboratory conditions. To increase the accuracy of measurements, corrections are introduced into their readings, taking into account the external conditions in which the measurements were carried out. In addition, laboratory measuring instruments are used to verify control measuring instruments. Exemplary measuring instruments are designed to transfer the size of units from standards to working measuring instruments, that is, they serve for their verification. Reference- a measuring instrument that provides reproduction and storage of a unit of physical quantity for transmitting its size to measuring instruments lower in the verification scheme.

Analog measuring device - a measuring device whose readings or output signal are a continuous function of changes in the quantity being measured

Analog measuring instruments, as a rule, provide direct measurements; the measurement result is read on a scale. The mode of measurements performed by analog measuring instruments is static. Most analog measuring instruments are pointer instruments with a fixed scale and a movable arrow, the movement of which (rotation or linear movement) relative to the scale is functionally one-to-one related to the value of the measured quantity. Other types of analog measuring instruments: - with a fixed pointer or other pointer and a moving scale, - with a linear indicator in the form of a strip combined with a scale, the length of which is functionally one-to-one related to the value of the measured quantity (for example, a mercury thermometer).

One of the possible classification schemes for analog measuring instruments is shown in Fig. 1.2.

Electromechanical devices are those devices whose conversion devices do not contain electronic, transistor or ionic units.

Electronic devices are those devices whose conversion device contains electronic, transistor or ionic units.

Showing instruments are devices that only allow readings.

Registering devices – those that provide for recording readings.

In analog devices direct conversion(actions) (Fig. 1.3) the input signal X is converted by one or more converters P1, P2, P3, ... in the bottom direction from input to output.

In analog devices (Fig. 1.4) the input value X is compensated by the XK value, which is the output value Y transformed by an inverse conversion circuit (inverse converters β 1, β 2, β 3, ..., β n).

Analog device circuits balancing transformation may include nodes covered by local feedbackβ 1 (Fig. 1.5), however, the determining factor is the presence of a common negative feedback β 2 from the output to the input.

To devices mixed conversion(Fig. 1.6 a, b) include devices in the structure of which negative feedback is introduced, which does not cover all links of direct conversion.

By purpose, there are devices for measuring current, voltage, frequency, devices for measuring parameters of electrical circuits, for analyzing signal characteristics, etc.

Instruments designed to measure several quantities are called combined.

Devices operating on both direct and alternating current are called universal.

digital measuring instrument

measuring device, in which the results of measuring a continuous quantity (voltage, current, electrical resistance, pressure, temperature, etc.) are automatically converted into discrete signals displayed as numbers on a digital indicator. Digital measuring instruments must include analog-to-digital converter, converting analog signal, received by the sensitive element (sensor), into a digital code. Digital measuring instruments are characterized by significantly higher measurement accuracy compared to analog measuring instruments, convenience and objectivity of reading. The accuracy of the count depends on the number of digits on the digital indicator. Numerous digital measuring instruments are available: watch, thermometers, scales, tonometers (arterial blood pressure meters), etc.

The CIP consists of two mandatory nodes; analog-to-digital converter (ADC) and digital readout device (OA). The ADC produces a code in accordance with the value of the measured quantity. The op-amp reflects this value in digital form. ADCs are also used in measuring, information control and other systems and are produced by industry as independent measuring instruments.

Metrological and other technical characteristics of the CIP are determined by the method of conversion to code. In digital measuring instruments intended for measuring electrical quantities, the sequential counting method and the bit-by-bit balancing method are used. Accordingly, a distinction is made between sequential counting CIPs and bit-by-bit balancing CIPs (pulse code). Depending on what value of the quantity is measured, CIPs are divided into devices for measuring instantaneous values ​​and devices for measuring the average value over a certain period of time (integrating).

According to the type of measured value, CIPs are divided into voltmeters, ohmmeters, frequency meters, phase meters, multimeters (combined), which provide the ability to measure several electrical quantities and a number of parameters of electrical circuits.

According to the area of ​​application, laboratory, system and switchboard CIPs are distinguished.

CIPs are complex; their functional parts are made on the basis of electronic elements, mainly integrated circuits. In modern digital digital information centers, functional units that convert analog signals are usually based on microelectronic operational amplifiers.

Let's take a simplified look at the most commonly used nodes.

Triggers consist of a device with two states of stable equilibrium, capable of jumping from one state to another using an external signal. After such a transition, the new stable state is maintained until another external signal changes it.

Recalculation devices (PU) are used to perform various tasks, for example, to divide the pulse frequency, to convert a number-pulse code into binary, etc.

If the PU is equipped with an op-amp to display the circuit state number, then it is possible to count the pulses arriving at the PU input, i.e. in this case, you can get a pulse counter.

Sign indicators are used to obtain readings in digital form in the form of special gas-discharge lamps or segmented sign indicators (liquid crystals, LEDs, electroluminescent strips, etc. are used as luminous elements),

Keys - These are devices that perform the functions of switches and switches. Electronic switches are mainly used on diodes, transistors, and other elements of electronic circuits.

Logic elements implement logical functions. The input and output values ​​of these elements are variables that take only two values ​​-1 and 0. Let's consider the basic logical elements, which make it possible to implement any logical function by connecting them.

The OR logic gate is an addition function, has several inputs and one output, which takes the value 1 if at least one input value is 1 and takes the value 0 if all inputs are 0;

The NOT logical element is a negation function (if the input has a value of 0, then the output will be 1 and vice versa) is used for inversion;

The logical AND function is a multiplication function that has several inputs and one output, which takes the value 1 if all inputs are 1 and takes the value 0 if at least one input is 0. The AND element is called a matching circuit and can be used as a logical switch, one of the input signals of which serves as a control signal.

Logic elements are performed both on discrete devices (diodes, transistors, resistors) and in the form of integrated circuits.

Decoders - these are devices for converting codes of one type into others.

3 Calibration and verification of measuring instruments

Calibration of measuring instruments- a set of operations performed to determine and confirm the actual values ​​of metrological characteristics and (or) suitability for use of a measuring instrument. The definition is similar to verification, from which calibration is distinguished by the fact that it applies to measuring instruments that are not subject to state metrological control and supervision, i.e. in fact. Calibration combines the functions previously performed during metrological certification and departmental verification of measuring instruments.

Measuring instruments that are not within the scope of state control and supervision (or used outside the scope of GMKiN) may be subject to calibration, but it is necessary to control their metrological characteristics, for example, when releasing measuring instruments from production or repair, when importing, during operation, rental and sale. Calibration of measuring instruments is carried out by calibration laboratories or in accordance with the terminology accepted in Russia “metrological services of legal entities” using standards subordinate to state standards of units of quantities. Calibration tools (standards) are subject to mandatory verification and, when calibration work is carried out, must have valid verification certificates.

Calibration results allow you to determine:

actual values ​​of the measured quantity; amendments to the readings of measuring instruments;

error of measuring instruments.

Main principle difference between calibration and verification, is that calibration is not part of the conformity assessment procedure. Confirmation of conformity is only verification, during calibration, the actual values ​​of metrological characteristics are determined and it is rather a research work. As a rule, due to the lack of special techniques, calibration is carried out according to verification methods for calibrated or similar measuring instruments. However, calibration may differ from verification, both in the direction of simplifying and in the direction of complicating the procedure. When calibrating, it is quite legitimate to pose the problem of determining the error characteristics of a measuring instrument only at one point in the measurement range and under conditions different from normal ones.

The results of calibration of measuring instruments are certified calibration mark, applied to measuring instruments or a calibration certificate, as well as an entry in operational documents.

Unlike verification, SI calibration is a voluntary procedure and can be performed by any metrological service. Accreditation for the right to calibrate is also a voluntary (not mandatory) procedure and is needed to a greater extent for the recognition of calibration results by third-party institutions and to improve the image of the enterprise.

3 3Verification of measuring instruments

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

The operation of measuring instruments that have not undergone timely verification may lead to the receipt of false information about the progress of the technological process. In this case, the difference between the obtained measurements and the actual values ​​is not predictable. Possible results of this situation: disruption of security systems, release of defective products, accidents of technological equipment. Elimination of consequences is associated with significant time and economic losses.

The verification of measuring instruments is entrusted to persons accredited in this area. Persons using measuring instruments are responsible for timely provision of means for verification.

1.4.1 Types of measuring instruments

According to their metrological purpose, measuring instruments are divided into exemplary and working.

Exemplary are intended for verification of other measuring instruments, both working and exemplary, of less high accuracy.

Workers measuring instruments are designed to measure the sizes of quantities necessary in various human activities.

The essence of dividing measuring instruments into exemplary and working ones is not in design or accuracy, but in their purpose.

Measuring instruments include:

Measures designed to reproduce a physical quantity of a given size. There are single-valued and multi-valued measures, as well as sets of measures (weights, quartz oscillators, etc.). Measures that reproduce physical quantities of the same size are called unambiguous. Multivalued measures can reproduce a number of sizes of a physical quantity, often even continuously filling a certain gap between certain boundaries. The most common multi-valued measures are the millimeter ruler, variometer and variable capacitor.

In sets and stores, individual measures can be combined in various combinations to reproduce some intermediate or total, but always discrete sizes of quantities. The stores are combined into one mechanical whole, equipped with special switches that are connected to reading devices. In contrast, a set usually consists of several measures that can perform their functions both individually and in various combinations with each other (a set of end length measures, a set of weights, a set of quality factors and inductance measures, etc.).

Comparison with the measure is carried out using special technical means - comparators(equal-arm scales, measuring bridge, etc.).

Unambiguous measures also include samples and reference substances. Standard samples of the composition and properties of substances and materials are specially designed bodies or samples of a substance of a certain and strictly regulated content, one of the properties of which, under certain conditions, is a quantity with a known value. These include samples of hardness, roughness, white surface, as well as standard samples used when calibrating instruments to determine the mechanical properties of materials. Sample substances play a large role in creating reference points when implementing scales. For example, pure zinc serves to reproduce a temperature of 419.58°C, gold - 1064.43°C.

Depending on the certification error, measures are divided into categories (measures of the 1st, 2nd, etc. categories), and the error of the measures is the basis for their division into classes. Measures assigned to one category or another are used to verify measuring instruments and are called exemplary.

Transducers- these are measuring instruments that process measuring information into a form convenient for further conversion, transmission, storage and processing, but, as a rule, not accessible to direct perception by an observer (thermocouples, measuring amplifiers, etc.).

The quantity being converted is called input, and the result of the transformation is day off size. The relationship between them is specified by the transformation function (static characteristic). If, as a result of the transformation, the physical nature of the quantity does not change, and the transformation function is linear, then the transformer is called large-scale, or amplifier(voltage amplifiers, measuring microscopes, electronic amplifiers). The word “amplifier” is usually used with a definition that is assigned to it depending on the type of quantity being converted (voltage amplifier, hydraulic amplifier) ​​or on the type of individual transformations occurring in it (tube amplifier, jet amplifier).

In those cases when the input quantity in the converter is converted into a quantity of another physical nature, it is named after the types of these quantities (electromechanical, pneumocapacitive, and so on).

Based on the space occupied in the device, converters (Fig. 3.1) are divided into: primary, to which the directly measured physical quantity is supplied; transmitting, at the output of which quantities are formed that are convenient for their registration and transmission over a distance; intermediate, occupying a place in the measuring circuit after the primary ones.

Rice. 3.1. Conversion of measuring information: 1 - sensitive element;
2 - primary converter; 3 - intermediate converters;
4 - transmitting converter

Measuring instruments refer to measuring instruments designed to obtain measurement information about the quantity to be measured in a form convenient for perception by the observer.

The most widespread direct acting devices, when used, the measured value is subjected to a series of sequential transformations in one direction, that is, without returning to the original value. Direct-acting instruments include most pressure gauges, thermometers, ammeters, voltmeters, etc.

They have significantly greater accuracy capabilities comparison devices, intended for comparison of measured quantities with quantities whose values ​​are known. Comparison is carried out using compensation or bridge circuits. Compensatory circuits are used to compare active quantities, that is, those that carry a certain supply of energy (forces, pressures and torques, electrical voltages and currents, brightness of radiation sources, etc.). The comparison is carried out by including these quantities side by side in a single circuit and observing their difference effect. Instruments such as equal-arm and half-arm scales (comparison of the force effects of mass action on a lever), deadweight and deadweight manometric and vacuum gauge instruments (comparison of the force effects of measured pressure and mass measures on a piston), etc. work on this principle.

To compare passive magnitudes (electrical, hydraulic, pneumatic and other resistances), bridge circuits such as electric balanced or unbalanced bridges are used.

According to the method of counting the values ​​of measured quantities, devices are divided into showing, including analog And digital, and on registering.

The most widely used are analog instruments, the reading devices of which consist of two elements - a scale and an indicator, one of which is connected to the moving system of the device, and the other to the body. In digital instruments, reading is carried out using mechanical, electronic or other digital reading devices.

According to the method of recording the measured value, recording instruments are divided into self-writing And printing. In recording instruments (for example, a barograph or a loop oscilloscope), the recording of readings is a graph or diagram. In printing devices, information about the value of the measured quantity is provided in numerical form on a paper tape.

Automatic comparison instruments are most often produced in the form of combined instruments, in which a scale or digital reading is combined with recording on a diagram or printing of measurement results.

1. Auxiliary measuring instruments. This group includes instruments for measuring quantities that affect the metrological properties of another measuring instrument during its use or verification. Readings from auxiliary measuring instruments are used to calculate corrections to measurement results (for example, thermometers for measuring ambient temperature when working with deadweight testers) or to monitor the maintenance of the values ​​of influencing quantities within specified limits (for example, psychrometers for measuring humidity for precise interference length measurements) .
2. Measuring installations. To measure any value or several values ​​at the same time, sometimes one measuring device is not enough. In these cases, entire complexes of measuring instruments (measures, transducers, measuring instruments and auxiliary equipment) located in one place and functionally integrated with each other are created, designed to generate a signal of measurement information in a form convenient for direct perception by the observer.
3. Measuring systems are means and devices that are geographically separated and connected by communication channels. Information can be presented in a form convenient both for direct perception and for automatic processing, transmission and use in automated control systems.

Technical devices designed to detect (indicate) physical properties are called indicators(compass needle, litmus paper). With the help of indicators, only the presence of a measurable physical quantity of the property of matter that interests us is established. An example of an indicator is the indicator of the amount of gasoline in a car's gas tank.

1. Curriculum for higher educational institutions in the specialty i-54 01 04 Metrological support of information systems and networks Coordinated with the Educational and Methodological Directorate

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   S.V. Lyalkov, Associate Professor of the Department of Metrology and Standardization of the Educational Institution “Belarusian State University of Informatics and Radio Electronics”,

2. Gram for higher educational institutions in the specialty i-54 01 04 metrological support of information systems and networks special disciplines in 3 parts part 1 Minsk 2006

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   Development of practical skills in the use of methods and means of measurement, testing and control to implement a quality management system for the production of printed products.

4. Lecture notes 2010 Contents 1 Instruments for measuring process parameters 4 1Measurements for pressure 12

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5. Contents general issues of metrological support of measuring systems 9 Bryukhanov V. A. 9

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   Metrological support of measuring systems. / Collection of reports of the international scientific and technical conference. Ed. A.A. Danilova. – Penza, 2005.

Measuring instrument

Measuring instrument- a technical device intended for measurements, having standardized metrological characteristics, reproducing and (or) storing a unit of physical quantity, the size of which is taken unchanged (within the established error) for a known time interval. The Law of the Russian Federation “On Ensuring the Uniformity of Measurements” defines a measuring instrument as a technical means intended for measurements. The formal decision to classify a technical device as a measuring instrument is made by the Federal Agency for Technical Regulation and Metrology.

Classification of measuring instruments

By technical purpose:

• measure of physical quantity - a measuring instrument designed to reproduce and (or) store a physical quantity of one or more specified sizes, the values ​​of which are expressed in established units and are known with the required accuracy;
• measuring device - a measuring instrument designed to obtain the values ​​of a measured physical quantity within a specified range;
• measuring transducer - a technical device with standard metrological characteristics, used to convert a measured value into another value or measuring signal, convenient for processing, storage, further transformations, indication or transmission;
• measuring installation (measuring machine) - a set of functionally combined measures, measuring instruments, and other devices, intended for measuring one or more physical quantities and located in one place
• measuring system - a set of functionally combined measures, measuring instruments, measuring transducers, computers and other technical means located at different points of a controlled object, etc. for the purpose of measuring one or more physical quantities characteristic of this object and generating measuring signals in different purposes;
• measuring and computing complex - a functionally integrated set of measuring instruments, computers and auxiliary devices, designed to perform a specific measuring task as part of a measuring system.

• automatic;
• automated;
• manual.

• working measuring instruments.

According to the significance of the measured physical quantity:

• the main means of measuring the physical quantity whose value must be obtained in accordance with the measurement task;
• auxiliary measuring instruments of that physical quantity, the influence of which on the main measuring instrument or measurement object must be taken into account in order to obtain measurement results of the required accuracy.

According to measuring physical and chemical parameters:

• for measuring temperature;
• pressure;
• consumption and quantity;
• solution concentration;
• for level measurement, etc.

Metrological characteristics of measuring instruments

For a measuring instrument of an approved type, a certificate (formerly a certificate) of approval of the type of measuring instrument is issued.

Only measuring instruments included in the state register of measuring instruments approved for use in the Russian Federation are subject to verification. After the verification procedure, a verification certificate is issued. Other technical devices are subject to calibration. After the calibration procedure, a calibration certificate is issued.