SU1420410A1 - Method of testing measurement instruments - Google Patents

Abstract

This invention relates to instrumentation technology. The purpose of the invention is to simplify the method of checking in conditions other than normal, and without an exemplary instrument. In the device, the operation associated with the setting of the setpoint characteristics of the reference device with the reference device under operating conditions is replaced with the transferring characteristics of the real settingter under the same conditions and recalculated into the time scale. 2 Il.

Description

SL C

11420410

 The invention relates to the control-nr measuring technique, in particular to | methods of calibrating instruments, and can be used when calibrating instruments for measuring pressure, voltage, etc. , . The purpose of the invention is to simplify the method of checking under conditions different from

During calibration, the device is installed according to FIG. 2 and the input of the device under test-5 under conditions different from normal (the operating conditions of the instrument calibration) 5 serves the measured value X from the setting device with the same fixed value X (in the general case with other parameters a) by opening the switch off of the normal, and without the exemplary addition of bodies 2, the change in the measurement of the monitor is recorded.

1 In FIG. 1 presents: 1 Hz (t) is the characteristic of the setpoint of the Measured value in time, it is midday in normal conditions with POM with

| q $ on a model device; X (t) is also a characteristic assigned under the conditions of operation with (using a scanned instrument;: X ,, (t) .- a characteristic of the setting device –– JB of operating conditions obtained from one point X, tp, obtained by meter;

x j, Ctn) - the characteristic of the setter.

my values in time of change.), and

of this curve, the POINT t, (CM "

FIG. one).

Record the achievement of the value X (measured value at the input of the instrument being checked using a 4 .- meter (and mark the point tp, X,) ...) (since the measured value is fed through the accumulator, then ha: the pattern of its change under working conditions is the same as in normal, in this case the exponential is the curve XD (t). However, the time constant of the transition process under operating conditions will be different than in normal, due to various external factors and parameters of the drive.

obtained by recalculating the characteristics of Xn (t) into a function of tj ..

{FIG. 2 shows a device I for implementing a method of checking-on an example-device for checking pressure sensors.

; A device for realizing the method; calibration of pressure meters with a pressure setting device in the form of source 1 of fixed pressure X, (switch 2 and accumulator 3. The sensor supplies pressure to the inlet from meter 4 fixed pressure start Xj and 1 {d input turn pressure gauge 5 connected to a recording device 6.

The method is implemented as follows.

First, under normal conditions, the characteristic is removed) under normal conditions with an exemplary instrument. In this case, instead of the instrument being turned on. 2 install an exemplary appliance. To do this, under normal conditions, the measured value X from the setpoint generator with drive 3 is opened to the input of the sample device by opening the switch 2 and the change in the measured value in time XflCt is recorded using the reference device.

Record the time t to achieve the value of X (measured value at the input of the reference instrument with the help of meter 4 (parameters), (to), X, X (- passport data of the setting device).

During calibration, the device is installed according to FIG. 2 and the input of the device under test-5 under conditions different from normal (the operating conditions of the instrument calibration) 5 serves the measured value X from the setting device with the same fixed value X (in the general case with other parameters ) by opening the switch 2 and fix the change in the measurement

my values in time of change.), and

of this curve, the POINT t, (CM "

FIG. one).

Record the achievement of the value X (measured value at the input of the instrument being checked using a 4 .- meter (and mark the point tp, X,) ...) (since the measured value is fed through the accumulator, then ha: the pattern of its change under working conditions is the same as in normal, in this case the exponential is the curve XD (t). However, the time constant of the transition process under operating conditions will be different than in normal, due to various external factors and parameters of the drive.

Recalculate the characteristic of the setpoint adjuster, taken with the help of a rotatable instrument Xn (t) as a function of

given time H ,.

t- according to the formula

0

where t

P

t 5

0

values of reduced and infinite time; tp, tp is the time to reach the same final values of the measured value at the instrument input,. . and the value of the measured by the testable instrument X as a function of the reduced time t.p-Xn (tn) determines the error of the device b. X according to the difference of the curves -Xц (t) and Xn (tt,) for different values of t;

five

According to the proposed method, the dependence Xn (t) ,. created under the operating conditions at the input of the scanned instrument, results in normal conditions X3 (t),

Sequential, timeless, destabilization of the characteristics of the setter with the help of t. using a model instrument and a test instrument (a test one), it is possible to remove a characteristic XtiCt), only once in the factory conditions and attach it as a passport data of the instrument. This allows self test of the instrument in working conditions. x without a model device.

314

using only one source of measured value with only one fixed value, and one meter 4 of this value only ONE value. The verification method is simplified.

In the proposed technical solution, the operation associated with the destabilization of the characteristics of the setter to the reference devices under operating conditions is replaced by the removal of the transient characteristic of the real setter under the same conditions (Xd, X ,, t,) and recalculated in the time scale. .

Claims (1)

Invention Formula Method of calibration of measuring devices by comparison of characteristics. unit of measured value, obtained with the help of verified and exemplary devices, characterized in that, in order to simplify five 0 five 0 104 The calibration process uses a drive with a fixed initial level of the measured value as the unit of the measured value. X and with the initial characteristic X (t) in the form of exponential, which is initially obtained under normal conditions using an exemplary device, then during calibration under operating conditions remove the characteristic X (t) of the setter with the help of a calibrated device, which is recalculated as a function of the reduced time tц, obtaining the characteristic. Xf, (ti), with:  : where tp is the time to reach some identical value of the measured quantity X ,, respectively, according to the characteristic X (t) and X, (t), and t is the value of the current time, and by: the obtained characteristic XnCt) is compared with the characteristic XnCt), one X / y (n (i) fae.2