SU1290217A1 - Method of calibration checking of instrument equipment - Google Patents

Abstract

This invention relates to the field of metrology. The aim of the invention is to reduce the volume and simplify the calibration. The proposed method is as follows. A test signal is connected to the input of the instrument to be tested. Starting from a certain value, equal values of the test signal are formed. The corresponding measurement results are recorded. According to the readings of the instrument, the instrument establishes one of the previously formed values of the test signal. This signal is connected to an exemplary instrument and its actual value is measured, which corresponds to the previously recorded readings of the instrument being tested, thus judging its error. One way to form equal-to-one signal values is to successively add a test signal to a signal, the value of which is determined by comparison block 2. To do this, use a device containing key element 1, comparison block 2, adder + and a testable device 3. Block 2 compare is set to the specified value X ass signal. At the input of the device 3, a certain value of the signal X and B is applied to the materials of the invention, other methods of forming equidistant values of the signal, as well as some variants of the proposed method of calibration of the instruments are indicated. 5 hp f-ly. 3 il. o W O) X ass. Yu

Description

112

The invention relates to metrology and can advantageously be used in the metrological calibration of measuring instruments.

The aim of the invention is to reduce the volume and simplify the calibration.

The method is as follows.

At first, the signal is connected only to the input of the device being checked. The initial value of the signal may coincide with the beginning or end of the measurement range. In this case, the beginning of the range is more preferable, since for many measuring instruments it is zero and provides a simple estimate (without the use of exemplary means) of the error of zero or the adaptive component of the error of the instrument being tested.

The change in the initial value of the test signal is carried out in such a way as to ensure at the output of the device under test a measurement of the measurement results corresponding to the equal values of the signal. Specific examples of the formation of such equal values and the corresponding measurements of the c1-shchut test signal connection circuits shown in Figs 1-3,

The formation of equidistant values of the test signal at the input must be carried out in such a way that any subsequent value of the test signal differs from the previous one, including the initial value X, by the same constant value. Essential to the realization of this condition and the entire verification in general is that during these operations with the input signal, knowledge of the actual values of the signal or the value of its increment A is not required.

Assume that during the verification process, equal values of the test signals were formed at the input and the corresponding readings were recorded at the output of the device under test. A number of results were obtained

V °

° t:

X,

A - + X „a. °

2A + X.

{)

KA - Hey

. Sn

PA

Zs

2

n- x

+ X

where X, ..., X are the readings of the instrument being checked;

a t f is the actual conversion coefficients of the instrument to be tested, corresponding to the generated values of the test signal; a - nominal coefficient

convertible instrument transforms (usually unchanged for certain a priori known portions of the range);

A - constant increment of the test signal; K is the serial number of the increment. The first and subsequent differences of the obtained measurement results are determined.

X

nd x, a

2 2 - X, 2A

aj-a,

thirty

yK X - X., KA

Ek - AKM

five

The sign of the increment A is known, therefore the sign of the first differences is determined by the difference in the values of the transformation coefficients

To and allows to judge, taking into account that

you can write SK km

 but

+ aa 0

0

five

- U and c ..

five

a, - ЗЗк-, U а, - uan-i where & a is the deviation of the real value

coefficient of the nominal increase or decrease in error in certain parts of the range of indications. The second D u, j, -u,

U2

and funnel: eating differences

  k k-1

ALLOW to determine the order of non-linearity of the real function of transforming the instrument being tested and the most characteristic parts of the function (characteristic breaks, its curvature, the degree of increase of the error in certain areas). Then, according to the indications of the device being tested at its input,

one of the previously generated test signal values,,

Depending on the information obtained in the analysis of the first and subsequent differences, one of the readings of the instrument being checked is selected, for example, the corresponding one

maximum error or maximum reading of the device. In this case, one of the values of the test signal should be zero.

The actual value of the set test signal is measured with a sample meter.

X,

X.

where X .. is a real value

N

signal.

The number K of increments of the test signal needed to increase the value of the signal from O to X is determined.

Then the actual value of the increment A is

A-K-

and each of the previously obtained indications (1) can be compared with the real value of the test signal

(2)

The validity of recent computational operations is based on the constancy of the increments of the test signals.

The values of the errors corresponding to the previously obtained indications of the device being turned on are determined as the difference of the values of the signals entering in (2).

In the event that the error values thus established are close to their normalized values, the information on the first and subsequent differences of the measurement results is again attracted and it is concluded that there is an error exceeding the values obtained.

The operations of connecting the test signal to the input of the device being tested and forming its equidistant values implement the following; shimm way.

One way is that equal signal values are generated by

Summation of the test signal connected to the input of the device under test with a signal whose value is determined by a comparison unit, for example, a measuring instrument.

Dp of this, for example (Fig. 1), an adjustable test signal through a series-connected controlled key element I, 6 / JOK 2 comparison and an adder is connected to the input of a rotating device 3. At the input of the device 3, at the same time, some value of the signal is given

0 Comparison block 2 can be a measurement tool, an indicator tool or a threshold element set to a certain set value X

bum

test signal.

The value of the signal X is changed. At the moment of equality X with some given value (ed determines the number of sections to be turned

measurement range) disconnect the test signal X and feed the generated increment A into the adder, which for this circuit simultaneously performs the role of a signal accumulator and provides its connection to the input of the device under test 3. At its output, record the measurement X, the signal X + A. Repeat until the occurrence of

at the output of the checked instrument 3, the measurement result X, which is close to the limiting value of the range of the instrument readings 3. The previously indicated processing of the measurement results of the test signal is carried out.

I. .

The formation of equidistant values of the test signal is also carried out in cases where

The type of signal does not allow simple (natural) summation at the input of the device being scanned or existing 1st accumulators (signal accumulators) can affect the accuracy of the calibration. The successive summation of a test signal, for example, an electrical signal connected to the input of a test instrument, with a signal whose value is determined by the comparison unit, can be carried out according to the circuit shown in Fig. 2.

In this case, the test signal Hz at the input of the device under test

pa 4 is obtained by summing the signals from control a1x of sources 5 and 6. The signal from source 6 determines the initial value of the test signal X, which can be zero or coincide with the beginning (end) of the measuring range of the device 4. Equal increments A form by means of the signal source 5, the comparator unit 7 and the key element 8, the Comparison Unit 7 controls the signal change at the output of the source 5 and compares its value with the specified increment value Xsdd.

The real accuracy of matching the realized increment A to the given value X & a, d is not significant. The above mentioned devices and operations are required only to ensure the equality of each subsequent increment A to all previous ones, which for a relatively short verification period can be achieved due to the natural stability of the parameters and characteristics of source 5 and block 7. Signal source 5 and comparison block 7 can replace with the source of the constant signal X, which for the verification period provides some inequality. well-known, but stable signal value.

Managed key element 8 implements the connection of increment A to the adder according to a specific algorithm. The sequence of operations for this exemplary implementation (FIG. 2) is as follows.

The measuring device 4 measures the initial value of the test signal, the result obtained is recorded in the control block 9, which opens the key element 8, and that caN & iM provides the connection to

increment adder A. The initial value of the signal Xd from source 6 is summed up with increment A and simultaneously acts on the input of the instrument being checked, the output of which is the measurement result X.

This result is stored in control block 9, which closes key element 8 (turns off increment A from the adder) and issues a command to change the signal from source 6. The measured values of this signal in block 9 control

five

0 5

0

five

compared with the previous result X (measurement of the total value of the signal X and increment A, At the moment of equality of these values (according to the indications of the device being turned)) control unit 9 gives commands to stop the change in the magnitude of the signal from source 6 and to open the key element 8. Summation occurs increments of A and the signal from source 6, equal to the sum of the initial value of X and the previous increment of A, the last equality is provided fairly strictly, since it does not depend on the metrological characteristics of the calibrated polarization Boron 4 and its stability is determined by the coefficient conversion to the same point in a short range interm; / current time between step E indicated previously,

Further, the sequence of operations is similar.

Sum: signal from source 6 can be performed with a negative value of increment A, if the initial value X of the signal corresponds to the limit value of the range of indications of the instrument being scanned. The actual value of X in this case may be unknown if it is established that one of the measurement results corresponds to a zero value of the signal from source 6,

The given example of the scheme provides a simple automation of the calibration of measuring instruments for electrical and other continuous quantities for which it is difficult to precisely fix the total effect. ,

It is possible to further simplify the proposed method of verification in terms of the formation of equally spaced values of the test signal by successively summing the signal connected to the input of the test instrument with equal values of increments. For this, the increment value is determined directly by a measuring instrument,

As an example, the calibration scheme shown in FIG. 3 is shown. To calibrate the measuring device 10, two adjustable signal sources 11 and 12 are used, two control units 13 and 14, key elements 15 and 16. Formation of constant increment A is carried out

A signal source 12, a key element 16, a measuring device 10 and a control unit 14 controlling the output signal values X from the signal source 12. For this, the control unit 14 records the value of a constant increment of the measurement result X, dd, corresponding to a certain value of the signal increment A. The control unit 14 with the closed element 15 and the open 16 controls the change in the signal at the output of the source 12 until the result of its measurement coincides with given value

hello

Then by the commands of block 14

The control stops the signal change from the source 12 and opens the key element 15. The total value of the initial value of the signal from the source 11 and the increment A from the source 12 form at the output of the measuring device 10.

The result of measuring this total value goes to control unit 13, which stores it and issues commands to close key element 6 and change the signal from source 11. This signal is continuously fed to the input of measuring device 10 and its results in control block 13 are compared with previously recorded the measurement result X + A, At the moment of coincidence of these measurement results, the control unit 13 issues commands to stop the signal change from the source 11, transfer the control to the block 14 to form increments A and the discovery of the key element 16.

The control unit 14, regulating the signal change from the source 12 according to the readings of the device 10, generates an increment signal A. Then it issues a command to the source 1 2, prohibiting the signal change, and opening the key element 15. Thus, a new signal is formed at the input of the measuring device 10 the value of the test signal different from the one previously stored in block 13 by a constant value. The measurement result is stored and. similar operations are carried out to change the signal from the source 1 1 until the moment when the result of its measurement coincides with the new value in the memory of the block- 13.

about

Thus carried out the sequential summation of signals

0

0

five

from source 11 in increments of A, from source I2 of the signal, form equal values of the signals at the input of the verified instrument 10 over the entire range of its readings. The measurement results are processed according to the previously specified algorithm. The links between the circuit elements and the verification scheme itself may be somewhat different in terms of the composition of the elements.

The formation of equal values of the test signal at the input of the device being tested is also possible in another way. To do this, a regulated signal source is connected to the input of the instrument to be tested and, starting with a certain known value, for example, zero, uniformly increases (decreases) the signal size. At the output of the device being tested, the measurement results are recorded at the time of the beginning of the measurement and at equal intervals of time,

In this case, a means of measuring time and realizing the timing of the time reference and the beginning of the signal change is necessary, which is practical for any information-measuring system.

The method of verification is also realized when connecting the initial value of a signal (for example, an electric signal) through the known signal dividing devices 5, and no higher (exemplary) level of accuracy of the dividers is required. This is due to the fact that it is necessary not to determine the actual value of the increment of the Signal, which is sorbed by the divider, but only the constancy of these increments for each subsequent value of the input signal.

5 Similarly, the equal values of the test signal are generated by multiplying the initial value of the signal by certain coefficients in the scale amplifier. Processing operations

The measurement results of the test signals do not differ from the previously discussed options.

0

0

The method before industrial application, depending on the instrument being scanned, in the form of a signal measured by it, requires the selection of specific devices necessary to implement the totality of its operations.

912902;

Claims (4)

Invention Formula I, A method of calibrating measuring instruments based on connecting a test signal to the inputs of a calibrated and exemplary measuring instrument, which is different. By the fact that, in order to reduce the volume and simplify the verification, the test signal is initially connected only to the input of the device being tested and, starting with some, for example, zero, form equal values of the test signal fix the corresponding measurement results, according to the indications one of the previously formed values of the test signal is installed, then this signal is sampled to the reference instrument, its actual value is measured, which corresponds to the previously recorded the readings of the instrument being checked and, according to the indications of these instruments, the accuracy of the instrument being checked, 2. Method POP1, characterized in that the first and subsequent differences in the measurement results of the test signal are determined, the degree of nonlinearity of the real conversion function of the device under test in certain parts of its measurement range is determined, the possibility of increasing the error in the intervals between directly controlled points of the range, then, if necessary, or re-perform all operations with the test signal while reducing 7 10 the constant value of its constant increment, or, by means of a testable instrument, form a test signal for the maximum depth range and measure its value with an exemplary measuring instrument, 3. Method POP1, characterized in that equal values of the test signal are formed by successively summing the test signal connected to the input of the device under test with the signal the value of which is determined by the comparison unit, for example, a measuring instrument. 4. The method according to p. 3, which differs from and with the fact that the magnitude of the increment of the test signal is first determined directly by the first electronic device, and then summed with the test signal connected to its input, 5, non.l method, characterized in that the formation of equidistant test values (signal is carried out by connecting a uniformly increasing (decreasing) test signal to the input of the test instrument and fixing the measurement results at regular intervals of time 6, Method pop, characterized in that the equally significant values of the test signal are carried out by dividing (multiplying) the initial value of the test signal applied to the input of the device under test using dividers or scaling transducers of the input signal. Editor N.Gorvat Compiled by A. Zaborn Tehred A. KravchukKorrektor L. Patay Order 7896/42 Circulation 752 Subscription VNIIPI USSR State Committee for Inventions and Discoveries 4/5, Moscow, Zh-35, Raushsk nab. 113035 Production and printing company, Uzhgorod, Proektna St., 4 fie.Z