SU930185A1 - Device for automatic checking of electromeasuring instruments - Google Patents

Description

The invention relates to a measurement technique and can be used in the construction of calibration systems.

A device for calibrating electrical measuring instruments is known, comprising two opto-electronic converters forming a movable unit, an analyzer of output signals of converters, a tracking system moving the movable unit following the indicator of the device being turned, a time interval converter into the number of pulses, a reversible counter, a generator clock pulses, a stepper motor and a voltage switch; with this, the inputs of the time interval to the number of pulses are connected to the output an recuperators output signals of the transducers, and the output - to the input of down counter, the output of which through a clock generator coupled to the stepper motor, the output shaft of which is coupled to voltage switch connected to the power metal emomu device (1.

This device does not provide the required accuracy due to the dynamic errors of the measuring device and the exemplary source of the voltage.

Also known is an installation for automatic calibration of electrical instruments, comprising a reference signal source, an optoelectronic converter unit (OEP), an OEP movement device, a pulse shaping unit, a programmer, an error calculator, and a magnetic device for recording signals, the first and the inputs of which are connected via A gaiter device with a pulse shaping unit, and its outputs are connected to an error calculator 2.

The disadvantages of this setup include the complexity of the verification process, due to the use of a magnetic signal recorder and a sinusoidal signal generator as the source of the reference signal. The device of magnetic recording of signals, in addition to the complexity of the installation / also leads to a noticeable decrease in its reliability.

The purpose of the invention is to improve the accuracy and reliability of the device.

The goal is achieved by the fact that a device for automatic calibration of electrical measuring instruments containing serially connected reference source of a constant signal and an exemplary divider, a block of optical-electronic converters (OED), the first inputs of which are connected through a communication channel with scale marks and a pointer device, the second - with the output of the locating movement of opto-electronic converters, and the outputs - with the inputs of a two-channel pulse shaper, the first output of which is connected to the first m input of the first key, and the second with the second input of the first key and the input of the program block, the first output of which is connected to the second input of the model divider, the second - to the first input of the adder, and the third to the first input of the arithmetic unit, the second input of which is connected to the output the adder has a frequency divider, an exemplary frequency generator, a time interval former and a second key, the output of the frequency divider is connected to the input of the optical-electronic converter displacement unit, and the input is via the first key from the output generator of exemplary frequency and the first input of the time interval generator, the second input of which is connected to the fourth output of the program block, the first output - to the second input of the adder, and the second - to the first input of the second key, the first input of which is connected to the output of the reference divider, and the output - input of the instrument being checked.

The drawing shows a block diagram of the proposed device.

The device includes an OEP block 1, an OEP transfer block 2, a two-channel shaper 3 pulses, a divider 4 frequencies, a first key 5, a generator of a standard frequency, a shaper of 7 time intervals, a second key 8, an exemplary divider 9, a reference source 10 constant signal, program block 11, adder 12, arithmetic block 13. Number 14 denotes the device being checked.

The OEP block 1 is used to convert the light, reflected from significant marks and the pointer on BeeptaMoro device 14, into electrical impulses. Therefore, it contains two optoelectronic converters rigidly interconnected. Significant marks of the scale fall into the field of view of one of them, and the instrument pointer is in the field of view of the other. Unit 1 OEP is equipped with unit 2 movement, with which it moves along the scale of the instrument to be tested. 14 Unit

2 movements are made discrete. The output of each of the OEP is connected to one of two pulse formers of 3 pulses located in a two-channel driver. The moving unit 2 through the divider 4 frequencies and the first key 5 is connected to the output of the generator 6 of exemplary frequency, which through the shaper 7 time intervals is also connected to the control input of the second key 8. The signal input of the switch 8 is connected through the exemplary divider 9 to the reference source 10 the constant signal and the output are connected to the input of the testable device 14. The outputs of the block of the formers of 3 pulses are connected to the control inputs of the first key 5, and one of them, from which the pulses of combining the pointer with significant marks are connected, is connected also with the input of the program block 11. The program block 11 serves to set the algorithm of the device operation depending on the technical characteristics of the scanned device 14 (measurement limit and the number of significant marks). The program can be entered into it either with the help of switches (buttons) or with the help of punched cards. The program block 11 has four outputs, the first of which is connected with the control input of the second key 8, the second with the control input of the driver 7 time intervals, the third with one of the inputs of the adder 12, and the fourth with the second input of the arithmetic unit 13. The second the input of the adder 12 is connected to the second output of the driver 7 time intervals, and the output to the second input of the arithmetic unit 13.

The device implements a method for checking electrical measuring instruments, based on using signals (voltage, current) of a rectangular instrument as input signals of a rectangular instrument and moving the pointer of a calibrated instrument by varying the duty cycle of rectangular pulses.

The device works as follows.

Before starting the verification, the program unit 11 introduces the program of operation of the device, which includes a set of commands for the restructuring of the model divider 9 and the generator of 7 time intervals. Commands, arriving at the model divider 9, set its state for each significant mark of the device under test 14. As a result, the output of the model divider 9 is set to a predetermined value of the constant signal (voltage, current), the nominal value of which is formed by the source 10 constant this signal. Commands from program block 11 to the shaper of 7 times of the NELX intervals are used to set the nominal value of the duration of the rectangular signals applied to the device being turned on and the discretization of its adjustment. The pulse duration and the discreteness of its adjustment during the verification process are determined by the characteristics of the instrument being tested (measurement limit, number of significant marks, accuracy class). The operation of the device begins at the operator's signal and occurs in the following sequence. First, the key 5 is opened and the pulses from the generator of the exemplary frequency b through this key and the divider 4 frequencies arrive at the OEP movement block 2, which is made discrete. The division factor of 4 times the frequency is chosen based on the allowed speed of movement of the block 1 OEP. The unit 2 moves the OEP unit 1 into motion and moves it until the light beam of one of the unit's OEP hits the first significant mark ;, the testable device 14. At this moment, at one of the outputs of the two-channel impulse generator 3 a pulse is generated, which A key 5 enters one of the control inputs. The key 5 closes and thereby stops the access of pulses from the generator 6 of the reference frequency to the divider 4 frequencies and further to the block 2 of movement. The motion of the OEP block is stopped and it is set by pressing the first significant mark of the instrument to be scanned 14. After this, the program block 11 issues a command to rebuild the exemplary divider 9 and the former 7 time intervals, the former 7 performs the formation of time intervals somewhat shorter than the nominal duration of the pr signals. of a rectangular shape supplied to the object being checked. This is done so that the indicator of the instrument to be checked 14 does not always reach the checked mark. The control-time signals from the output of the former 7 are stored on the key 8, opening it for the duration of the pulse duration. Thereby, at the output of the key 8, signals (voltage or current) of the right angle form are formed, which arrive at the top of the device 14, and set its pointer to a certain position. After several periods of the signal being formed, the number of which is determined by the transient time processes in the calibrated device 14, the shaper of 7 time intervals begins to rebuild the duration of the generated signal with a certain incremental step. The pointer of the scanned instrument 14 approaches the checked mark, and at the moment of their coincidence, a signal appears at the output of another OEP unit 1, which enters the impulse driver 3, and a pulse is generated at the corresponding output of the latter, arriving at the control unit 11 Key input 5. By this signal, a code of the nominal value of the duration of rectangular pulses corresponding to the actual signal value in the checked elevation of the instrument is entered into the adder 12 from the program block 11, and from the driver 7 time intervals the code of the actual duration value. In the adder 12, a code difference is formed, i.e. DT code. This code, as well as code C, the number of the mark being checked and the number of all significant marks are entered into the arithmetic unit 13, in which the reduced error in the instrument's checked mark is determined. The absolute and relative errors and variation of indications can be calculated by the arithmetic unit. Simultaneously with this control signal from the output of the two-channel pulse generator 3, key 5 is opened and the displacement unit 2 sets up the OEP block 1 similarly to the previous one in the next significant mark of the device under test 14. Then, the exemplary divider 9 and the former 7 time intervals are rearranged according to the program block 11. in the future, the operation of the device is completely repeated with the forward and reverse direction of movement of the pointer of the instrument 14. In each of the significant marks of the instrument, the errors are determined, the codes of which can be deduced for registration, or can be analyzed in the arithmetic unit 13 by comparing them with the limit error for the conclusion: does the device being tested conform to the accuracy class. The increase in accuracy is due to the exclusion of dynamic errors that occur during continuous tracking of the pointer during its movements, since the readings are actually taken in a static mode, as well as dynamic errors of the measuring device and signal source, which inevitably arise during adjustment by linear /

Claims (1)

Claim A device for automatic 'verification of electrical measuring instruments, containing a continuously connected reference source of constant. ·' · Signal and an exemplary divider, a block of optical ^ electronic converters, the first inputs of which are connected through the channel with the marks of the scale and pointer of the device being verified, the second - with the output of the displacement unit optoelectronic converters, and the outputs - with the inputs of a two-channel pulse shaper, the course of which is connected to the first key, and the second input of the first key and the gram block the first first output, the first input with the second input, the output of the splitter 15, the second with the first input of the adder, and the third with the first input of the arithmetic unit, the second input of which is connected to the output of the adder, characterized in that, in order to increase the accuracy and the reliability of the device, a frequency divider, a reference frequency generator, a shaper of time intervals and a second key are introduced into it, the output of the frequency divider connected to the input of the moving block of the optoelectronic converter, and the input through the first key with the output of a non-radiator of the reference frequency and the first input of the time interval shaper, the second input of which is connected to the fourth output of the program unit, the first output - with the second input of the adder, and the second - with the first input of the second key, the first input of which is connected to the output of the model divider, and the output - the input of the device being verified.