Purpose, structure and principle of operation of a millivoltmeter

3.3 Temperature compensation

Conclusion

Literature

Annex 1

Appendix 2

Introduction

Electrical measurements occupy a special place in measuring technology. Modern energy and electronics rely on the measurement of electrical quantities. Currently, instruments have been developed and produced that can be used to measure more than 50 electrical quantities. The list of electrical quantities includes current, voltage, frequency, ratio of currents and voltages, resistance, capacitance, inductance, power, etc. The variety of measured quantities also determined the variety of technical means that implement measurements.

The purpose of the work is to analyze the maintenance and repair of electrical measuring instruments, including the millivoltmeter.

Objectives of the thesis:

Analyze the literature on the problem under study;

Review the basic concepts and general information from measurement theory;

Identify the classification of electrical measuring instruments;

Analyze the concepts of measurement errors, accuracy classes and classification of measuring instruments;

Consider the purpose, structure, technical data, characteristics and principle of operation of the millivoltmeter, its operational verification using the compensation method;

Analyze the maintenance and repair of electrical measuring instruments, including a millivoltmeter, namely: disassembling and assembling the measuring mechanism; adjustment, calibration and testing; temperature compensation;

Consider the organization of the instrumentation and automation repair service, the structure of the instrumentation and automation equipment repair area, the organization of the instrumentation mechanic's workplace;

Draw appropriate conclusions.

Chapter 1. Electrical measuring instruments

1.1 Basic concepts and general information from measurement theory

The readings (signals) of electrical measuring instruments are used to assess the operation of various electrical devices and the condition of electrical equipment, in particular the state of insulation. Electrical measuring instruments are distinguished by high sensitivity, measurement accuracy, reliability and ease of implementation.

Along with measuring electrical quantities - current, voltage, electrical power, magnetic flux, capacitance, frequency, etc. - they can also be used to measure non-electrical quantities.

The readings of electrical measuring instruments can be transmitted over long distances (telemetering), they can be used to directly influence production processes (automatic control); with their help, the progress of controlled processes is recorded, for example by recording on tape, etc.

The use of semiconductor technology has significantly expanded the scope of application of electrical measuring instruments.

To measure any physical quantity means to find its value experimentally using special technical means.

For various measured electrical quantities there are their own measuring instruments, the so-called measures. For example, by measures e. d.s. normal elements serve as measures of electrical resistance, measuring resistors serve as measures of inductance, measuring inductors serve as measures of inductance, capacitors of constant capacitance serve as measures of electrical capacitance, etc.

In practice, various measurement methods are used to measure various physical quantities. All measurements based on the method of obtaining the result are divided into direct and indirect. In direct measurement, the value of a quantity is obtained directly from experimental data. In indirect measurement, the desired value of a quantity is found by counting using a known relationship between this quantity and values ​​obtained from direct measurements. Thus, the resistance of a section of a circuit can be determined by measuring the current flowing through it and the applied voltage, followed by calculating this resistance from Ohm's law.

The most widely used methods in electrical measuring technology are direct measurement methods, since they are usually simpler and require less time.

In electrical measuring technology, the comparison method is also used, which is based on comparing the measured value with a reproducible measure. The comparison method can be compensatory or bridge. An example of the application of the compensation method is measuring voltage by comparing its value with the value of e. d.s. normal element. An example of the bridge method is resistance measurement using a four-arm bridge circuit. Measurements using the compensation and bridge methods are very accurate, but they require complex measuring equipment.

With any measurement, errors are inevitable, i.e. deviations of the measurement result from the true value of the measured value, which are caused, on the one hand, by the variability of the parameters of the elements of the measuring device, the imperfection of the measuring mechanism (for example, the presence of friction, etc.), and the influence of external factors (the presence of magnetic and electric fields), changes in ambient temperature, etc., and on the other hand, the imperfection of human senses and other random factors. The difference between the instrument reading A P and the actual value of the measured quantity A D, expressed in units of the measured value, is called the absolute measurement error:

The reciprocal of the absolute error is called the correction:

(2)

To obtain the true value of the measured quantity, it is necessary to add a correction to the measured value:

(3)

To assess the accuracy of the measurement performed, the relative error is used δ , which is the ratio of the absolute error to the true value of the measured value, usually expressed as a percentage:

(4)

It should be noted that it is very inconvenient to evaluate the accuracy of, for example, pointer measuring instruments using relative errors, since for them the absolute error along the entire scale is practically constant, therefore, as the value of the measured value decreases, the relative error (4) increases. When working with pointer instruments, it is recommended to select the measurement limits of a value so as not to use the initial part of the instrument scale, i.e., read the readings on the scale closer to its end.

The accuracy of measuring instruments is assessed by the given errors, i.e. by the ratio of the absolute error to the standard value expressed as a percentage A H:

(5)

The normalizing value of a measuring device is the conventionally accepted value of the measured quantity, which can be equal to the upper measurement limit, measurement range, scale length, etc.

Instrument errors are divided into the main one, inherent in the device under normal conditions of use due to imperfections in its design and execution, and additional, due to the influence of various external factors on the instrument readings.

Normal operating conditions are considered to be ambient temperature (20 5) ° C with relative humidity (65 15)%, atmospheric pressure (750 30) mm Hg. Art., in the absence of external magnetic fields, in the normal operating position of the device, etc. Under operating conditions other than normal, additional errors arise in electrical measuring instruments, which represent a change in the actual value of the measure (or instrument reading) that occurs when there is a deviation one of the external factors beyond the limits established for normal conditions.

The permissible value of the basic error of an electrical measuring instrument serves as the basis for determining its accuracy class. Thus, electrical measuring instruments are divided into eight classes according to the degree of accuracy: 0.05; 0.1; 0.2; 0.5; 1.0; 1.5; 2.5; 4.0, and the number indicating the accuracy class indicates the highest permissible value of the main error of the device (in percent). The accuracy class is indicated on the scale of each measuring device and is represented by a number circled.

The instrument scale is divided into divisions. The division value (or constant of the device) is the difference between the values ​​of a quantity that corresponds to two adjacent scale marks. Determination of the division value, for example, of a voltmeter and ammeter is carried out as follows: C U = U H /N- the number of volts per scale division; C I = I H /N- the number of amperes per scale division; N is the number of scale divisions of the corresponding device.

An important characteristic of the device is the sensitivity S, which, for example, for a voltmeter S U and ammeter S I, are defined as follows: S U = N/U H- number of scale divisions per 1 V; S I = N/I N- the number of scale divisions per 1 A.

1.2 Classification of electrical measuring instruments

Electrical measuring equipment and instruments can be classified according to a number of characteristics. Based on their functionality, this equipment and devices can be divided into means of collecting, processing and presenting measurement information and means of certification and verification.

Electrical measuring equipment can be divided into measures, systems, instruments and auxiliary devices according to their intended purpose. In addition, an important class of electrical measuring instruments consists of converters designed to convert electrical quantities in the process of measurement or conversion of measurement information.

According to the method of presenting measurement results, instruments and devices can be divided into indicating and recording.

According to the measurement method, electrical measuring equipment can be divided into direct assessment devices and comparison (balancing) devices.

According to the method of application and design, electrical measuring instruments and devices are divided into panel, portable and stationary.

According to measurement accuracy, instruments are divided into measuring instruments, in which errors are standardized; indicators, or extracurricular devices in which the measurement error is greater than that provided for by the relevant standards, and pointers in which the error is not standardized.

Based on the principle of action or physical phenomenon, the following large groups can be distinguished: electromechanical, electronic, thermoelectric and electrochemical.

Depending on the method of protecting the device circuitry from the influence of external conditions, the housings of the devices are divided into ordinary, water-, gas-, and dust-proof, hermetic, and explosion-proof.

Electrical measuring equipment is divided into the following groups:

1. Digital electrical measuring instruments. Analog-to-digital and digital-to-analog converters.

2. Testing installations and installations for measuring electrical and magnetic quantities.

3. Multifunctional and multichannel tools, measuring systems and measuring and computing complexes.

4. Panel analog devices.

5. Laboratory and portable instruments.

6. Measures and instruments for measuring electrical and magnetic quantities.

7. Electrical recording instruments.

8. Measuring transducers, amplifiers, transformers and stabilizers.

9. Electric meters.

10. Accessories, spare and auxiliary devices.

1.3 Concept of measurement errors, accuracy classes and classification of measuring instruments

The error (accuracy) of a measuring device is characterized by the difference between the readings of the device and the true value of the measured value. In technical measurements, the true value of the measured quantity cannot be accurately determined due to the existing errors of measuring instruments, which arise due to a number of factors inherent in the measuring instrument itself and changes in external conditions - magnetic and electric fields, ambient temperature and humidity, etc. d.

Instrumentation and automation equipment (I&A) is characterized by two types of errors: main and additional.

The main error characterizes the operation of the device under normal conditions specified by the manufacturer's technical specifications.

An additional error occurs in the device when one or more influencing quantities deviate from the required technical standards of the manufacturer.

Absolute error Dx is the difference between the readings of the working device x and the true (actual) value of the measured quantity x 0, i.e. Dx = X - X 0.

In measuring technology, relative and reduced errors are more acceptable.

The relative measurement error g rel is characterized by the ratio of the absolute error Dx to the actual value of the measured quantity x 0 (in percent), i.e.

g rel = (Dx / x 0) · 100%.

The reduced error g pr. is the ratio of the absolute error of the device Dx to the constant standard value x N for the device (measurement range, scale length, upper measurement limit), i.e.

g ex. = (Dx / x N) 100%.

The accuracy class of instrumentation and automation equipment is a generalized characteristic determined by the limits of permissible main and additional errors and parameters affecting the accuracy of measurements, the values ​​​​of which are established by standards. There are the following instrument accuracy classes: 0.02; 0.05; 0.1; 0.2; 0.5; 1; 1.5; 2.5; 4.0.

Measurement errors are divided into systematic and random.

Systematic error is characterized by repeatability in measurements, since the nature of its dependence on the measured value is known. Such errors are divided into permanent and temporary. Constants include errors in calibration of instruments, balancing of moving parts, etc. Temporary errors include errors associated with changes in the conditions of use of instruments.

Random error is a measurement error that changes according to an indefinite law during repeated measurements of any constant quantity.

The errors of measuring instruments are determined by comparing the readings of the standard and the instrument being repaired. When repairing and checking measuring instruments, instruments with an increased accuracy class of 0.02 are used as reference tools; 0.05; 0.1; 0.2.

In metrology - the science of measurements - all measuring instruments are classified mainly according to three criteria: by type of measuring instrument, principle of operation and metrological use.

By type of measuring instruments, measures, measuring devices and measuring installations and systems are distinguished.

A measure is a measuring instrument used to reproduce a given physical quantity.

A measuring device is a measuring instrument used to generate measurement information in a form suitable for control (visual, automatic recording and input into information systems).

Measuring installation (system) - a set of various measuring instruments (including sensors, converters) used to generate measurement information signals, process them and use them in automatic product quality control systems.

When classifying measuring instruments according to the principle of operation, the name uses the physical principle of operation of this device, for example, a magnetic gas analyzer, thermoelectric temperature transducer, etc. When classifying according to metrological purpose, working and standard measuring instruments are distinguished.

A working measuring instrument is a means used to estimate the value of the measured parameter (temperature, pressure, flow) when monitoring various technological processes.

Chapter 2. Millivoltmeter F5303

2.1 Purpose, structure and principle of operation of the millivoltmeter

Fig.1. Millivoltmeter F5303

The F5303 millivoltmeter is designed for measuring rms voltage values ​​in alternating current circuits with sinusoidal and distorted signal shapes (Fig. 1).

The operating principle of the device is based on the linear conversion of the root mean square value of the output reduced voltage into direct current, followed by its measurement by a magnetoelectric system device.

The millivoltmeter consists of six blocks: input; input amplifier; final amplifier; DC amplifier; calibrator; power and control.

The device is mounted on a horizontal chassis with a vertical front panel, in a metal case with holes for cooling.

Used for precise measurements in low-power circuits of electronic devices when checking, configuring, adjusting and repairing them (only in enclosed spaces).

2.2 Technical data and characteristics

Voltage measurement range, mV:

0,2 – 1; 0,6 – 3;

2 – 10; 6 – 30;

600 – 3*10 3 ;

(2 ÷ 10) *10 3 ;

(6 ÷ 30) *10 3 ;

(20 ÷ 100) *10 3 ;

(60 ÷ 300) *10 3 ;

Limits of permissible basic error in the normal frequency range as a percentage of the highest value of the measurement ranges: in voltage measurement ranges with the highest values ​​from 10 mV to 300 V - no more than ±0.5; in voltage measurement ranges with the highest values ​​1; 3 mV - no more than ±1.0.

The largest values ​​of voltage measurement ranges:

o 1; 3; 10; thirty; 100; 300 mV;

o 1; 3; 10; thirty; 100; 300 V.

Normal frequency range is from 50 Hz to 100 MHz.

The operating frequency range for measurements is from 10 to 50 Hz and from 100 kHz to 10 MHz.

Power supply from AC mains with frequency (50 ± 1) Hz and voltage (220 ± 22) V.

2.3 Operational verification of the millivoltmeter using the compensation method

Devices of the highest classes 0.1 - 0.2 and 0.5 are verified using the compensation method on a potentiometric installation.

Verification of millivoltmeters whose nominal limit is higher than 20 mV, as well as voltmeters with an upper measurement limit not exceeding the nominal limit of the potentiometer, is carried out according to schemes 1 and 2 (Fig. 2, Fig. 3).

Scheme 1 is used in cases where the voltage is measured directly at the terminals of the millivoltmeter, and scheme 2 when the voltage is measured at the ends of the connecting conductors of the device.

If the nominal limit of the millivoltmeter is less than 20 mV, then the circuit shown in Fig. 4 is used.

Fig.2. Scheme for testing millivoltmeters with a limit of mV h > 20 mV without calibrated connecting wires

Fig.3. Scheme for testing millivoltmeters with a limit of mV h > 20 mV together with calibrated connecting wires

Fig.4. Scheme for testing millivoltmeters with a measurement limit of less than 20 mV

Chapter 3. Maintenance and repair of electrical measuring instruments (millivoltmeter)

3.1 Disassembly and assembly of the measuring mechanism

Due to the wide variety of designs of measuring mechanisms of devices, it is difficult to describe all the operations of disassembling and assembling devices. However, most operations are common to any device design, including a millivoltmeter.

Homogeneous repair operations must be performed by craftsmen of various qualifications. Repair work on devices of classes 1 – 1.5 – 2.5 – 4 is carried out by persons with qualifications of 4 – 6 categories. Repair of devices of class 0.2 and 0.5, complex and special devices is carried out by electromechanics of 7-8 categories and technicians with special education.

Disassembly and assembly are critical operations when repairing devices, so these operations must be performed carefully and thoroughly. If disassembled carelessly, individual parts will deteriorate, resulting in new ones being added to existing faults. Before you begin disassembling the devices, you need to come up with a general procedure and feasibility of carrying out complete or partial disassembly.

Complete disassembly is carried out during major repairs associated with rewinding frames, coils, resistances, manufacturing and replacing burnt and destroyed parts. Complete disassembly involves separating individual parts from each other. During an average repair, in most cases, incomplete disassembly of all components of the device is performed. In this case, the repair is limited to removing the moving system, replacing the thrust bearings and filling cores, assembling the moving system, adjusting and adjusting the instrument readings to the scale. Re-calibration of the device during an average repair is carried out only if the scale is tarnished, dirty, and in other cases the scale should be preserved with the same digital marks. One of the quality indicators of average repair is the production of devices with the same scale.

Disassembly and assembly must be done using watch tweezers, screwdrivers, small electric soldering irons with a power of 20 - 30 - 50 W, watch cutters, oval pliers, pliers and specially made keys, screwdrivers, etc. Based on the identified malfunctions of the device, disassembly begins. In this case, the following order is observed. First, the casing cover is removed and the inside of the device is cleaned of dust and dirt. Then the moment of the antimagnetic spring is determined and the scale (underscale) is unscrewed.

When overhauling complex and multi-range devices, the circuit is removed and all resistances are measured (recorded in the master’s workbook).

Then the outer end of the spring is unsoldered. To do this, the arrow is retracted by hand to the maximum, and the spring is twisted. A heated electric soldering iron is applied to the spring holder, and the spring, unsoldered, slides off the spring holder. Now you can begin further disassembly. Use a special wrench, combination screwdriver or tweezers to unscrew the locknut and the mandrel with the thrust bearing. The wing of the air or magnetic damper is removed, and for devices with a square cross-section of the box, the damper cover is removed.

After performing these operations, the moving system of the device is removed, the thrust bearings and the ends of the axles or cores are checked. To do this, they are examined under a microscope. If necessary, the cores are removed for refilling using hand vises, side cutters or wire cutters. The captured core is slightly rotated under a simultaneous axial force.

Further disassembly of the moving system into its component parts is carried out in cases where it is not possible to remove the core (the axle is removed). But before disassembling the moving system into parts, it is necessary to record the relative position of the parts attached to the axis: the arrows relative to the iron petal and the stabilizer wing, as well as the parts along the axis (along the height). To fix the location of the arrow, petal and wing of the stabilizer, a device is made in which there is a hole and recesses for the passage of the axis and piston.

The millivoltmeter is disassembled in the following order: the cover or casing of the device is removed, the torque of the springs is measured, an internal inspection is performed, the electrical circuit of the device is removed, the circuit circuits are checked, the resistance is measured; the underframe is removed, the conductors going to the spring holders are unsoldered, then the cage of the moving system is removed.

Particularly carefully inspect and clean the parts and assemblies of the moving and fixed parts; the ends of the axes are pierced through lint-free paper or pierced into the core of a sunflower. The deepening of the thrust bearing is wiped with a stick dipped in alcohol, the chamber and the damper wing are cleaned.

When assembling devices, special attention must be paid to carefully installing the moving systems in the supports and adjusting the gaps. the sequence of assembly operations is the reverse of their sequence during disassembly. The procedure for assembling the device is as follows.

First, the moving system is assembled. In this case, it is necessary to maintain the same relative position of the parts that were fixed during disassembly. The moving system is installed in the device supports. The lower mandrel is firmly secured with a lock nut, and the upper mandrel is used to make the final installation of the axle in the centers of the thrust bearings. The gap is adjusted so that it is of normal size. In this case, it is necessary to turn the mandrel 1/8 - 1/4 turn, while controlling the amount of the gap.

If the mandrel is not carefully assembled and screwed in until it stops, the thrust bearing (stone) and the axle are destroyed. Even slight pressure on the moving system causes large specific pressures between the ends of the axles and the recesses of the thrust bearings. In this case, secondary disassembly of the moving system is required.

After adjusting the gap, it is checked whether the moving system moves freely. The damper wing and petal should not touch the walls of the stilling chamber and the coil frame. To move the moving system along the axis, the mandrels are alternately unscrewed and screwed in at the same number of revolutions.

Then the outer end of the spring is soldered to the spring holder so that the arrow is located at the zero mark. After soldering the spring, the possibility of free movement of the moving system is checked again.

3.2 Adjustment, calibration and testing

Upon completion of the alteration of the device or after a major overhaul, the scale limit is adjusted. For a normally adjusted device, the needle deviation from the original should be 90°. In this case, the zero and maximum scale marks are located symmetrically at the same level.

To adjust the scale limit, the repaired device is connected to an electrical circuit with smooth current adjustment from zero to maximum. Using a sharp pencil, place a zero mark at the end of the arrow when there is no current in the circuit. Then measure the distance from the screw securing the scale to the zero mark and transfer this distance with a measuring compass to the other end of the scale. In this case, they correspond to the end of the moved arrow. After this, turn on the current and bring the arrow of the control device to the upper limit for which the device is manufactured. If the needle of the adjustable device does not reach the end point of the scale, then the magnetic shunt moves towards the center of the magnetic field until the needle reaches the maximum mark. If the arrow deviates beyond the limit mark, the shunt moves in the opposite direction, i.e. the magnetic field decreases. It is not recommended to remove the shunt during adjustment.

After adjusting the scale limit, begin calibrating the device. When calibrating, the choice of the number of digital marks and the division value is important. The device is calibrated as follows.

1. Set the arrow to the zero mark with the corrector and connect the device to the circuit with the reference device. Check that the pointer can move freely along the scale.

2. Using the reference instrument, set the needle of the instrument being calibrated to the nominal value.

3. Reducing the instrument readings, set the calculated calibration values ​​for the standard instrument and mark them with a pencil on the scale of the instrument being calibrated. If the scale is uneven, it is recommended to apply intermediate points between the digital marks.

4. Turn off the current and notice whether the arrow has returned to zero; if not, then the arrow is set to zero using a corrector.

In the same order, calibration marks are applied when moving the arrow from zero to the nominal value.

After repairing the device, they check again whether the moving system moves freely, inspect the internal parts of the device and record the readings of the standard and repaired devices when the measured value changes from maximum to zero and back. The pointer of the device being tested is brought to the digital marks smoothly. The results of the inspection are recorded in a special protocol.

A diagram for checking electromagnetic system devices is given in Appendix 1.

We summarize the calculated data for calibration and testing of the millivoltmeter in Table 1.

Table 1. Calculated data for millivoltmeter

3.3 Temperature compensation

The presence in the circuits of devices of wires and spiral springs, which are used to supply current to the moving system, leads to additional errors from temperature changes. According to GOST 1845-52, the error values ​​of the device due to temperature changes are strictly regulated.

To prevent the influence of temperature changes, the devices are equipped with temperature-compensated circuits. In devices with the simplest temperature compensation circuit, such as millivoltmeters, an additional resistance made of manganin or constantan is connected in series with the resistance of a frame or working coil made of copper wire (Fig. 5).

Fig.5. Millivoltmeter circuit with simple temperature compensation

A diagram of complex temperature compensation of a millivoltmeter is given in Appendix 2.

3.4 Organization of instrumentation and automation repair service, structure of the instrumentation and automation equipment repair area

Depending on the structure of the enterprise, the repair area for instrumentation and automation equipment, as well as the operation area for instrumentation and automation equipment, belongs to the instrumentation and automation workshop or the metrology department.

The management of the instrumentation and automation repair section is carried out by the section manager or senior foreman. The staffing schedule of the site depends on the range of control, measurement and regulation equipment in use, as well as the volume of work performed. At large enterprises with a wide range of instrumentation and automation equipment, the repair department includes a number of specialized repair units: temperature measurement and control devices; pressure, flow and level instruments; analytical instruments; instruments for measuring physical and chemical parameters; electrical and electronic instruments.

The main tasks of the site are the repair of instrumentation and automation equipment, their periodic verification, certification and submission of devices and measures within the established time frame to the State verification authorities.

Depending on the volume of repair work, the following types of repairs are distinguished: current, medium, major.

Current repairs of instrumentation and automation equipment are carried out by the operating personnel of the instrumentation and automation department.

Medium repair involves partial or complete disassembly and adjustment of measuring, control or other instrument systems; replacement of parts, cleaning of contact groups, assemblies and blocks.

A major overhaul involves the complete disassembly of a device or regulator with the replacement of parts and assemblies that have become unusable; calibration, production of new scales and testing of the device after repair on test benches with subsequent verification (state or departmental).

Device verification - determining whether the device meets all technical requirements for the device. Verification methods are determined by factory specifications, instructions and guidelines of the State Committee of Standards. Metrological supervision is carried out by verification of control equipment, measurements, metrological audit and metrological examination. Metrological supervision is carried out by a unified metrological service. State verification of instruments is carried out by the metrological service of the State Committee of Standards. In addition, individual enterprises are given the right to conduct departmental verification of certain groups of devices. At the same time, enterprises that have the right to departmental verification are issued a special stamp.

After satisfactory verification results, a verification stamp is applied to the front of the device or glass.

Measuring instruments are subjected to primary, periodic, extraordinary and inspection verifications. The timing of periodic verification of instruments (measuring instruments) is determined by the current standards (Table 2).

Table 2. Frequency of verification of measuring instruments

Note: GMS is the state metrological service, VMS is the departmental metrological service.

3.5 Organization of the instrumentation mechanic’s workplace

Depending on the structure of the enterprise, instrumentation mechanics perform both repair and operational work.

The task of operating instrumentation and automation equipment installed in production areas and workshops is to ensure uninterrupted, trouble-free operation of control, signaling and regulation devices installed in switchboards, consoles and individual circuits.

Repair and verification of instrumentation and automation equipment is carried out in instrumentation and automation workshops or the metrology department in order to determine the metrological characteristics of measuring instruments.

The workplace of an instrumentation mechanic involved in the operation of equipment has panels, consoles and mnemonic diagrams with installed equipment and devices; table-workbench with a source of adjustable alternating and direct current; testing devices and stands; in addition, the workplace must have the necessary technical documentation - installation and circuit diagrams of automation, instructions from device manufacturers; personal protective equipment for working in electrical installations up to 1000 V; voltage indicators and probes; devices for testing the performance of measuring instruments and automation elements.

Sanitary conditions must be maintained at the workplace: the area per workplace of an instrumentation mechanic is at least 4.5 m2, the air temperature in the room is (20±2)°C; In addition, supply and exhaust ventilation must work, and the workplace must be sufficiently lit.

For each device in operation, a passport is issued, which contains the necessary information about the device, the date of start of operation, information about repairs and verification.

The file cabinet for measuring instruments in use is stored in the area involved in repairs and verification. Certificates for standard and control measurement measures are also stored there.

To carry out repairs and verification, the site must have design documentation regulating the repair of each type of measuring equipment, as well as its verification. This documentation includes standards for medium and major repairs; consumption standards for spare parts and materials.

Storage of funds received for repairs and those that have undergone repairs and verification must be carried out separately. There are appropriate racks for storage; The maximum permissible load on each shelf is indicated by the corresponding tag.

Conclusion

The work summarizes the practice of repair and maintenance of electrical measuring instruments, including the millivoltmeter.

The advantages of electrical measuring instruments are ease of manufacture, low cost, absence of currents in the moving system, and resistance to overloads. The disadvantages include the low dynamic stability of the devices.

In the thesis we reviewed the basic concepts and general information from measurement theory; identified a classification of electrical measuring instruments; carried out an analysis of the literature on the problem under study; analyzed the concepts of measurement errors, accuracy classes and classification of measuring instruments; reviewed the purpose, structure, technical data, characteristics and operating principle of the millivoltmeter, its operational verification using the compensation method; analyzed the maintenance and repair of electrical measuring instruments, including a millivoltmeter, namely: disassembling and assembling the measuring mechanism; adjustment, calibration and testing; temperature compensation; reviewed the organization of the instrumentation and automation repair service, the structure of the instrumentation and automation equipment repair area, the organization of the instrumentation mechanic's workplace; made the appropriate conclusions.

This topic is very interesting and requires further study.

As a result of the work carried out, its goal was achieved and positive results were obtained in solving all the assigned tasks.

Literature

1. Arutyunov V.O. Calculation and design of electrical measuring instruments, Gosenergoizdat, 1956.

2. Minin G.P. Operation of electrical measuring instruments. – Leningrad, 1959.

3. Mikhailov P.A., Nesterov V.I. Repair of electrical measuring instruments, Gosenergoizdat, 1953.

4. Fremke A.V. and others. Electrical measurements. – L.: Energy, 1980.

5. Khlistunov V.N. Digital electrical measuring instruments. – M.: Energy, 1967.

6. Chistyakov M.N. A young worker's guide to electrical measuring instruments. – M.: Higher. school, 1990.

7. Shabalin S.A. Repair of electrical measuring instruments: Reference. metrologist's book. - M.: Standards Publishing House, 1989.

8. Shilonosov M.A. Electrical instrumentation. – Sverdlovsk, 1959.

9. Shkabardnya M.S. New electrical measuring instruments. - L.: Energy, 1974.

10. Electrical and magnetic measurements. Ed. E.G. Shramkova, ONTI, 1937.

Annex 1

Scheme for checking electromagnetic system devices

Appendix 2

Circuit of complex temperature compensation of a millivoltmeter

a – general diagram for the limits of 45 mV and 3 V; b, c, d – transformation of a complex circuit into a simple one (limit 45 mV); d, f, g – transformation of a complex circuit into a simple one (limit 3 c)

MINISTRY OF AGRICULTURE OF THE RUSSIAN FEDERATION FGOU VPO "Vologda State

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GENERAL PHYSICS

Laboratory workshop on the course “Physics” for students

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E.V.Slavorosova, art. Lecturer at the Department of Higher Mathematics and Physics,

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N.V. Kiseleva, Associate Professor of the Department of Higher Mathematics and Physics of VSMHA, Candidate of Technical Sciences,

A.E. Grishchenkova, senior lecturer at the Department of General and Applied Chemistry at VSMU.

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MEASUREMENT OF PHYSICAL QUANTITIES

AND CLASSIFICATION OF ERRORS

One of the main objectives of the laboratory workshop, in addition to promoting a better understanding of the ideas and laws of physics, is to develop in students the skills of independent practical work and, above all, the competent performance of measurements of physical quantities.

To measure a quantity means to find out how many times it contains a homogeneous quantity taken as a unit of measurement.

Directly measure this value ( direct measurement) happens very rarely. In most cases, not direct measurements of this quantity are made, but indirect- through quantities associated with the measured physical quantity by a certain functional dependence.

It is impossible to measure a physical quantity absolutely accurately, because Every measurement is accompanied by some error or inaccuracy. Measurement errors can be divided into two main groups: systematic and random.

Systematic errors are caused by factors acting in the same way when the same measurements are repeated many times. They arise most often from the imperfection of measuring instruments, from an insufficiently developed theory of experience, as well as from the use of inaccurate data for calculations.

Systematic errors always have a one-sided effect on the measurement result, only increasing or decreasing them. Detecting and eliminating these errors is often not easy, since it requires a painstaking and careful analysis of the method by which the measurements were made, as well as checking all measuring instruments.

Random errors arise due to a variety of both subjective and objective reasons: changes in voltage in the network (during electrical measurements), changes in temperature during the measurement process, inconvenient arrangement of instruments on the table, insufficient sensitivity of the experimenter to certain physiological sensations, excited state of the worker and others. All these reasons lead to the fact that several measurements of the same quantity give different results.

Thus, random errors include all those errors whose numerous causes are unknown or unclear to us. These errors are also not constant, and therefore, due to random circumstances, they can either increase or decrease the value of the measured value. Errors of this type obey the laws of probability theory established for random phenomena.

It is impossible to exclude random errors that arise during measurements, but it is possible to estimate the errors with which this or that result was obtained.

Sometimes they also talk about mistakes or miscalculations- these are errors that arise as a result of negligence in instrument readings and illegibility in recording their readings. Such errors do not obey any law. The only way to eliminate them is to carefully take repeated (control) measurements. These errors are not taken into account.

DETERMINATION OF ERRORS FOR DIRECT LINES

MEASUREMENTS

1. It is necessary to measure a certain quantity. Let N 1, N 2, N 3 ... N n- results of individual measurements of a given quantity, n- number of individual measurements. The closest to the true value of the measured quantity is the arithmetic mean of a series of individual measurements, i.e.

The results of individual measurements differ from the arithmetic mean. These deviations from the average are called absolute errors. The absolute error of a given measurement is the difference between the arithmetic mean and the given measurement. Absolute errors are usually denoted by the Greek letter delta () and placed in front of the value for which this error is found. Thus,

N 1 = N avg -N 1

N 2 = N avg -N 2

…………….. (2)

N n = N avg -N n

The absolute errors of individual measurements of a certain quantity characterize to some extent the accuracy of each measurement. They can have different meanings. The accuracy of the result of a series of measurements of one particular quantity, i.e. The accuracy of the arithmetic mean can naturally be characterized by a single number. The average absolute error is taken as such a characteristic. It is found by adding the absolute errors of individual measurements without taking into account their signs and dividing by the number of measurements:

Both signs are assigned to the mean absolute error. The measurement result, taking into account the error, is usually written in the form:

with the dimension of the measured quantity indicated outside the brackets. This entry means that the true value of the measured value lies in the range from N cp - N avg before N avg + N avg, those.

Obviously, the smaller the average absolute error N cp, the smaller the interval in which the true value of the measured value is contained N, and the more accurately this value is measured.

2. If the accuracy of the instrument is such that for any number of measurements the same number is obtained, lying somewhere between the scale divisions, then the given method for determining the error is not applicable. In this case, the measurement is performed once and the measurement result is written as follows:

Where N"- the desired measurement result;

N" cp- the average result, equal to the arithmetic mean of two values ​​corresponding to adjacent scale divisions, between which lies the remaining unknown value of the measured quantity;

Nnp- maximum error equal to half the scale of the instrument.

3. Often in works the values ​​of quantities measured in advance are given. In such cases, the absolute error is taken equal to its maximum value, i.e. equal to half one of the smallest digit represented in the number. For example, if given body weight m= 532.4 g. In this number, the smallest represented digit is tenths, then the absolute error Δ m=0.1/2 = 0.05 g, therefore:

m= (532.4 ± 0.05) g

To get a more accurate idea of ​​the measurements of a certain quantity and to be able to compare the accuracy of different measurements (including quantities of different dimensions), it is customary to find the relative error of the result. Relative error is the ratio of the absolute error to the value itself.

Usually only the average relative error of the measurement result is found "E", which is calculated as the ratio of the average absolute error of the measured value to its arithmetic mean value and is usually expressed as a percentage

It is convenient to determine errors for direct measurements using the following table.

ERROR IDENTIFICATION

FOR RESULTS OF INDIRECT MEASUREMENTS

In most cases, the desired physical quantity is a function of one or more measured quantities. To determine such a value, it is necessary to carry out a series of direct measurements of auxiliary quantities, and then, using the known relationships between these quantities (formulas of physical laws) and the tabulated values ​​of the constants included in these relationships, calculate the desired value. Next, knowing the errors made when measuring auxiliary quantities and the accuracy with which the tabulated values ​​are taken, it is necessary to find the possible error in the measurement result.

In cases where the desired value is found by elementary mathematical operations, the formulas given in the table can be used to determine the error of the result based on the errors in the source data.

These formulas are derived under the assumption that the errors of all initial data are small compared to the quantities themselves and that products, squares and higher degrees of errors can be neglected as quantities of the second order of smallness. In practice, these formulas can be used if the errors in the source data are of the order of 10% or less. In addition, when deriving the formulas, the most unfavorable combination of error signs in the source data was assumed, i.e. formulas determine the value of the maximum possible or maximum error of the result.

In the case when the calculation formula contains a combination of actions that is not in the table, errors should be found by sequentially applying these rules to each mathematical operation.

For example, the surface tension coefficient is calculated using the formula. We obtain a formula for calculating the absolute measurement error of a given value. To do this, we derive the relative error formula using the table:

And using the relative error formula, we get the absolute error from here.

GRAPHIC PROCESSING OF MEASUREMENT RESULTS

When processing measurement results, the graphical method is often used. This method happens to be necessary when it is necessary to trace the dependence of any physical quantity on another, for example y=f(x). To do this, make a series of observations of the desired quantity at for different values ​​of the variable X. For clarity, this dependence is depicted graphically.

In most cases, a rectangular coordinate system is used. Independent argument value X are plotted along the abscissa axis on an arbitrarily chosen scale, and values ​​are also plotted along the ordinate axis on an arbitrary scale at. The points obtained on the plane (Fig. 1) are connected by a curve, which is a graphic representation of the function y=f(x).

This curve is drawn smoothly, without sharp curvatures. It should cover as many points as possible or pass between them so that the points on both sides of it are evenly distributed. The curve is finally drawn using patterns in parts that overlap each other.

Using a curve depicting the dependence y=f(x), interpolation can be done graphically, i.e. find values at even for such values X, which were not directly observed, but which lie in the range from x 1 before x n. From any point in this interval you can draw an ordinate until it intersects with the curve; the length of these ordinates will represent the values ​​of the quantity at for the corresponding values X. Sometimes it is possible to find y=f(x) at values X, lying outside the measured interval (x 1 ,x n), by curve extrapolation y=f(x).

In addition to a coordinate system with a uniform scale, semi-logarithmic and logarithmic scales are used. The semi-logarithmic coordinate system (Fig. 2) is very convenient for constructing curves like y=ae k x. If the values X plotted on the x-axis (uniform scale), and the values at- along an uneven ordinate axis (logarithmic scale), then the dependence graph is a straight line.

To measure any physical quantity means to find its value experimentally using special technical means.

Basic concepts and general information from measurement theory

The readings (signals) of electrical measuring instruments are used to assess the operation of various electrical devices and the condition
electrical equipment, in particular the state of insulation. Electrical measurements
The devices are highly sensitive and accurate
measurements, reliability and ease of execution.

Along with measuring electrical quantities - current, voltage,
power of electrical energy, magnetic flux, capacitance, frequency
etc. - they can also be used to measure non-electrical quantities.

The readings of electrical measuring instruments can be transmitted to
long distances (telemetering), they can be used for non-
mediocre impact on production processes (automatic
ical regulation); with their help they record the progress of controlled
processes, for example by recording on tape, etc.

The use of semiconductor technology has significantly expanded
area of ​​application of electrical measuring instruments.

To measure any physical quantity means to find its value experimentally using special technical means.

For various measured electrical quantities there are their own measuring instruments, the so-called measures. For example, by measures e. d.s.
normal elements serve as measures of electrical resistance -
measuring resistors, inductance measures - measuring ca-
inductance bodies, measures of electrical capacitance - capacitors
constant capacity, etc.

In practice, to measure various physical quantities it is used
Various measurement methods are used. All measurements depending on
methods for obtaining results are divided into direct and indirect. At direct measurement the value of the quantity is obtained directly from experimental data. At indirect measurement the desired value of a quantity is found by counting using a known relationship between this quantity and values ​​obtained from direct measurements. Thus, the resistance of a section of a circuit can be determined by measuring the current flowing through it and the applied voltage, followed by calculating this resistance from Ohm’s law. Most
methods have become widespread in electrical measuring technology
direct measurement, since they are usually simpler and require less
time expenditure.

In electrical measuring technology they also use comparison method, which is based on a comparison of the measured value with a reproducible measure. The comparison method can be compensatory or bridge. Application example compensation method serves because
measuring voltage by comparing its value with the value of e. d.s.
normal element. Example bridge method is the measurement
resistance using a four-arm bridge circuit. Measurements
compensation and bridge methods are very accurate, but to test them
This requires sophisticated measuring technology.

At any measurement are inevitable errors, i.e. deviations
measurement result from the true value of the measured value,
which are determined, on the one hand, by the variability of parameters
elements of the measuring device, imperfection of the measuring device
mechanism (for example, the presence of friction, etc.), the influence of external
factors (presence of magnetic and electric fields), changes
ambient temperature, etc., and on the other hand, imperfect
the sensitivity of human senses and other random factors.
The difference between the reading of the A P device and the actual value
measured quantity A d, expressed in units of the measured quantity,
is called the absolute measurement error:

The reciprocal of the absolute error is called
amendment:

(9.2)

To obtain the true value of the measured value, it is necessary
You can add a correction to the measured value:

(9.3)

To assess the accuracy of the measurement performed, the relative
error δ, which is the ratio of the absolute
error to the true value of the measured quantity, expressed
usually in percentage:

(9.4)

It should be noted that using relative errors to evaluate
the accuracy of, for example, pointer measuring instruments is very inconvenient, since for them the absolute error along the entire scale
is practically constant, therefore, with a decrease in the value of the measured
the relative error (9.4) increases. Recommended for
When working with pointer instruments, select measurement limits of great
ranks so as not to use the initial part of the instrument scale, i.e.
count readings on the scale closer to its end.

The accuracy of measuring instruments is assessed by given
errors, i.e., according to the absolute ratio expressed as a percentage
error to the normalizing value A n:

The normalizing value of a measuring device is the conventionally accepted value of the measured quantity, which can be equal to
upper measurement limit, measurement range, scale length
and etc.

Instrument errors are divided into main, inherent
device under normal conditions of use due to imperfect
quality of its design and execution, and additional, conditioned
the influence of various external factors on the instrument readings.

Normal operating conditions are considered to be ambient temperature.
living environment (20 5)°C at relative humidity (65 15)%,
atmospheric pressure (750 30) mm Hg. Art., in the absence of external"
magnetic fields, in the normal operating position of the device, etc.
Under operating conditions other than normal, in electrical measurements
In real devices, additional errors arise, which
represent a change in the actual value of the measure (or
instrument readings) that occurs when one of the external
factors beyond the limits established for normal conditions.

Permissible value of the main error of the electrical measuring instrument
of the device serves as the basis for determining its accuracy class. So,
Electrical measuring instruments according to the degree of accuracy are divided into
eight classes: 0.05; 0.1; 0.2; 0.5; 1.0; 1.5; 2.5; 4.0, and the figure
denoting the accuracy class, indicates the highest permissible
the value of the basic error of the device (in percent). Accuracy class
indicated on the scale of each measuring instrument and represents
is the number circled.

The instrument scale is divided into divisions. Price division (or constant
device) is the difference in the values ​​of the quantity that corresponds
corresponds to two adjacent scale marks. Determining the division price,
For example, a voltmeter and an ammeter are produced as follows:
C U = U H /N - the number of volts per scale division;
C I = I H /N - number of amperes per scale division; N-
the number of scale divisions of the corresponding device.

An important characteristic of the device is the sensitivity S, which, for example, for a voltmeter S U and an ammeter S I, is determined
as follows: S U = N/U H - number of scale divisions per
at 1 V; S I = N/I N - number of scale divisions per 1 A.

Refusal in favor of the state– a customs procedure in which foreign goods are transferred into state ownership (federal property) without paying customs duties and without applying non-tariff regulation measures.

Only:

1) foreign goods permitted for import into the territory;

2) foreign goods permitted for free circulation in the customs territory

These conditions are enshrined in the code. But the code does not talk about other important conditions. These goods must be liquid – i.e. the price of these goods must be higher than the cost of selling them.

Placing goods under the customs procedure should not entail additional costs beyond those that can be covered by the sale of goods.

Another condition is the requirement to clean the goods. The goods must be “clean” in relation to third parties (should not be encumbered by the claims of third parties).

The Eurasian Commission determined list of goods, which cannot be placed under this procedure:

1) Cultural values

2) Any types of energy

3) Industrial waste

5) Weapons and ammunition

6) WMD (chemical, nuclear, bacteriological)

7) Technical documentation for creating weapons of mass destruction

8) Dual-use goods

9) High-frequency and radio-electronic transmitting devices

Any transformation or manifestation of the properties of a substance that occurs without changing its composition is called a physical phenomenon.

2.Matter and forms of its existence. Give examples.

Substance- this is one of the types matter. The word “matter” in science refers to everything that exists in the Universe.

Matter is what exists in the Universe regardless of our consciousness (celestial bodies, animals, etc.)

3. Observations and experiments in physics. Physical quantities. Measurement of physical quantities.

Much knowledge is gained by people from their own observations. To study a phenomenon, it is necessary first of all to observe it and, if possible, more than once.

Height, mass, speed, time, etc. are physical quantities.

A physical quantity can be measured.

To measure any quantity means to compare it with a homogeneous quantity taken as a unit.

In physics, permissible when measuring

4. The first position of the MKT and its experimental justification.
- a description of calculating the size of molecules from a photograph taken using a tunnel microscope;
-experience with paint;
- experiments on the expansion of solids, liquids and gases when heated.

A molecule of a substance is the smallest particle of a given substance.

For example, the smallest particle of water is a water molecule.

The smallest particle of sugar is a sugar molecule.

Molecule

Due to their small size, molecules are invisible to the naked eye or ordinary microscopes! But with the help of a special device - electron microscope- Can see. Molecules are made up of even smaller particles - atoms. There is mutual attraction between molecules. At the same time, there is repulsion between molecules and atoms. At distances comparable to the size of the molecules (atoms) themselves, attraction becomes more noticeable, and upon further approach, repulsion becomes more noticeable.

5. The second position of the MKT and its experimental justification.
-diffusion in solids, liquids and gases; comparison of the rate of diffusion.
-Brownian motion, its explanation; examples of Brownian motion in liquids and gases.

Very often in our lives we encounter all kinds of dimensions. "Measurement" is a concept that is used in various human activities. Later in the article, this concept will be examined from several angles, although many believe that it relates specifically to mathematical action. However, this is not quite true. Measurement data is used by people every day and in various areas of life, helping to build many processes.

Measurement concept

What does this word mean and what is its essence? Measurement is the establishment of the real value of a quantity using special means, devices and knowledge. For example, you need to find out what size blouse a girl needs. To do this, it is necessary to measure certain parameters of her body and derive from them the size of the desired clothing.

In this case, there are several size tables: European, American, Russian and letter. This information is readily available and we will not provide the mentioned tables in our article.

Let's just say that the key point in this case is the fact that we get a certain, specific size that was obtained by measurement. Thus, any girl can purchase things without even trying them on, but simply by looking at the size range or the tag on the clothing. Quite convenient, given the modern operation of cheap online stores.

About measuring instruments

Measurement is a concept that can be used anywhere, and people encounter it almost every day. In order to measure something or find any value, a lot of different methods are used. But there are also many tools specially created for these purposes.

Measuring instruments have their own specific classification. It includes various measures of quantities, measuring installations, instruments, converters, and systems. All of them exist in order to identify a certain value and measure it as accurately as possible. Some of these devices make direct contact with the measurement object.

In general, measuring instruments can be used and applied only when they are intended for the named purposes and are capable of maintaining the unit of measurement at a stable level for a certain time. Otherwise the result will be inaccurate.

Variety of speed

Also, every day people come across the concept of “speed”. We can talk about the speed of transport, human movement, water, wind and a host of other examples. However, for each of the objects it happens differently, using completely different methods and instruments:

• a device such as an atmometer is designed to measure the rate of evaporation of liquids;
• the nephoscope measures the direction of movement and speed of clouds;
• radar determines the speed of the vehicle;
• a stopwatch measures the time of various processes;
• anemometer - wind speed;
• the turntable allows you to clarify the speed of river flow;
• hemocoagulograph detects the rate of human blood clotting;
• The tachometer measures speed and rpm.

And there are many more such examples. Almost everything in this world can be measured, so the meaning of the word “measurement” is so multifaceted that it is sometimes difficult to imagine.

Measurements in physics

Many terms and concepts are closely related to each other. It would seem that a person is engaged in work every day at his workplace. And it is usually measured in wages, as well as time spent on it or other criteria. But there is another dimension of work, in this case mechanical. Naturally, there are several more scientific concepts. These include work in an electrical circuit, thermodynamics, and kinetic energy. As a rule, such work is measured in Joules, as well as in ergs.

Of course, these are not the only designations of work; there are other units of measurement used to designate physical quantities. But they all take one designation or another, depending on what kind of process they are measuring. Such quantities most often relate to scientific knowledge - to physics. They are studied in detail by schoolchildren and students. If you wish, you can study these concepts and quantities in depth: on your own, with the help of additional sources of information and resources, or by hiring a qualified teacher.

Information dimension

There is also such a thing as “information measurement”. It would seem, how can information be measured? Is this even possible? It turns out that it is quite possible. It just depends on what you mean by information. Since there are several definitions, there are different ones. The measurement of information occurs in technology, in everyday life and in information theory.

Its unit of measurement can be expressed in bits (the smallest) or bytes (the larger one). Derivatives from the named unit also differ: kilobytes, megabytes, gigabytes.

In addition, it is quite possible to measure information in the same way as, for example, energy or matter. Information assessment exists in two types: its measurability (objective assessment) and meaning (subjective assessment). An objective assessment of information is a rejection of the human senses; it is calculated using all kinds of sensors, devices, instruments that can provide much more data than human perception.

Method of measurement

As is already clear from the above, measurement is a method of studying the world as a whole. Of course, such a study occurs not only using the measurement method, but also through observations, experiments, and descriptions. A wide range of sciences in which measurement is used makes it possible to have not only specific information, but also accurate information. Most often, the data obtained during measurement is expressed in numbers or mathematical formulas.

Thus, it is easy to describe the size of figures, the speed of a process, the size and power of a device. Having seen this or that number, a person can easily understand the further characteristics of the desired process or object and use them. All this knowledge helps us every day in everyday life, at work, on the street or at home. After all, even the simple process of preparing dinner involves a measurement method.

Ancient quantities

It is easy to understand that each science has its own measurement values. Any person knows how seconds, minutes, hours, the speed of a car, the power of a light bulb and many other parameters of a particular object are expressed and designated. There are also very complex formulas, and quantities no less complex in their designation.

As a rule, such formulas and measurement values ​​are required by a narrower circle of people involved in a certain area. And a lot can depend on the possession of such information.

There are also many ancient values ​​that were used in the past. Are they used now? Certainly. They are simply translated into modern designations. Finding information about this process is quite easy. Therefore, if necessary, it will not be difficult for anyone to convert, for example, arshins into centimeters.

About measurement error

Complex processes can also include classes of measurements. More precisely, the accuracy classes of the means used for measurement. These are the final characteristics of certain devices, showing the degree of their accuracy. It is determined by the permissible error limits or other values ​​that can affect the level of accuracy.

A rather complex and incomprehensible definition for a person who does not understand this. However, an experienced specialist will not be hampered by such concepts. For example, you need to measure some quantity. For this, a certain measuring instrument is used. The readings of this remedy will be considered the result. But obtaining this result can be influenced by a number of factors, including a certain error. Each selected one has its own error. The permissible error limit is calculated using a special formula.

Areas of application of knowledge

There is a lot to be said about all the intricacies of the measurement process. And everyone will be able to obtain new and useful information on this issue. Measurement is a rather interesting method of obtaining any information, requiring a serious, responsible and high-quality approach.

Of course, when a housewife prepares a pie according to a special recipe, measuring in measuring cups the required amount of ingredients that are needed, she does it easily. But if you go into details in more detail, on a larger scale, then it is not difficult to understand that a lot in our lives depends on measurement data. When going to work in the morning, people want to know what the weather will be like, how to dress, and whether to take an umbrella with them. And for this, a person finds out the weather forecast. But weather data was also obtained by measuring many indicators - humidity, air temperature, atmospheric pressure, etc.

Simple and complex

Measurement is a process that comes in many varieties. This was mentioned above. Data can be obtained in various ways, using various objects, installations, instruments, and methods. However, devices can be divided according to their purpose. Some of them help to control, others help to clarify errors and deviations from them. Some are aimed at certain specific quantities that a person uses. The obtained data and values ​​are then converted into the necessary parameters using a specific method.

Perhaps the simplest measuring instrument is a ruler. With its help, you can obtain data on the length, height, width of an object. Naturally, this is not the only example. It has already been said about measuring cups. You can also mention floor and kitchen scales. In any case, such examples are available in a huge variety, and the presence of such devices often makes a person’s life much easier.

Measurement as a whole system

Indeed, the meaning of the word “measurement” is very great. The scope of application of this process is quite extensive. There are also a huge number of methods. It is also true that different countries have their own system of measurement and quantities. The name, the information contained, and the formulas for calculating any units may differ. The science that is closely concerned with the study of measures and precise measurement is called metrology.

There are also certain official documents and GOSTs that control quantities and measurement units. Many scientists have devoted and are devoting their activities to studying the measurement process, writing special books, developing formulas, and contributing to the acquisition of new knowledge on this topic. And every person on Earth uses this data in everyday life. Therefore, knowledge about measurement always remains relevant.