SU894629A1 - Devic for testing electric measuring instruments - Google Patents

Description

(54) DEVICE FOR TESTING ELECTRIC MEASUREMENT DEVICES

I

The invention relates to domestic equipment and can be used when checking dial gauge instruments.

A device for automated calibration of electrical measuring instruments is known, which contains an input signal source, a counting device made on the basis of an optoelectronic converter, and a measuring device with a source of reference voltages tl.

The drawback of the device is the great complexity, due to the fact that in order to improve the accuracy of verification, it is necessary to ensure synchronism of movement of the optoelectronic converter along the instrument scale with the rate of change of the input signal voltage, as well as dynamic errors due to reading at a varying input signal.

The closest in technical essence to the proposed is

2

device containing the input signal shaper applied to the instrument, the reference signal source, the input and reference signal difference meter, the capacitive sensor, the tips of the movable pens of which are placed on the protective glass of the instrument being scanned and combined with the mid-scale of the scale markers as well as 5klok registration maximum capacity, the input of which is connected. with the output of the capacitive sensor, and the output with the unit indicating the results of calibration 21.

15

The disadvantages of this device are complexity and low availability. the accuracy of the calibration result is due to the presence of dynamic errors, since the formation of the signal of maximum capacitance and the comparison of the input and reference signals takes place with a linear variation on the input signal.

The purpose of the invention is to simplify and increase the reliability of calibration.

This goal is achieved by the fact that a device for checking electrical measuring instruments, containing a source of a reference signal, a capacitive sensor and a maximum capacity recording unit, with the tips of the movable pens of a capacitive sensor placed on the protective glass of the instrument and aligned with the center of the calibrated scale marks, and the output of the capacitive the sensor is connected to the registration input of the maximum capacitance, the source of the alternating tolerance voltage and the adder are entered, the outputs of the reference signal sources and the alternating sign voltage tolerances are connected to the corresponding inputs of the adder, and the output of the latter is connected to the output buses of the instrument being turned

In the drawing P1Ya1, the block diagram of the proposed device.

It contains the source 1 of the reference signal and the source 2 of alternating tolerance voltage, adder 3. The output of the szmmmator is connected to the input of the calibrated mushroom 4. A capacitive sensor 5 is installed on the protective glass of the rotatable device, the tips of the moving pens of which are aligned with the centers of the detectable tick marks device. The capacitive sensor is connected to the maximum capacity recording unit 6.

The service works in the following way "

The source 1 of the reference signal creates a sequence of step voltages, increasing dich from zero to the maximum value, and then, in reverse order, decreasing to zero. The amplitudes of these voltages correspond to the nominal values of the calibrated scale marks. . Source 2 alternating tolerance voltage, for example, relay-resistor, produces two equal in magnitude but opposite in sign | level of voltages, the amplitudes of which correspond to the value of the permissible error of the device (t D) ..

The voltage A at the output of the relay-resistor source of alternating tolerance voltage is selected by the voltage of the power source and the values of the resistors connected to it, and the time relay changes at certain intervals

polarity of the power supply to the resistors. A positive voltage level (D) at the output of the source 2 alternating tolerance voltage acts for a time of increasing amplitudes of the step voltage at the output of the source 1 reference signal, and when they decrease the source 2 alternating voltage tolerance produces a negative voltage level (y. The amplitudes of the voltages produced by the sources 1 and 2 are summed in the adder 3 and from its output are fed to the input of the test instrument 4. Under the action of the total step voltage, the arrows are deflected the device to the right - when the age of the scientific research institute is of voltage amplitudes, and to the left when the voltage is decreasing. Since the amplitudes of the total voltage differ by D from the corresponding nominal values of the checked marks, then with each voltage jump the arrow of the serviceable device reaches the middle of the corresponding scale mark In this case, the maximum capacitance% is observed by the arrow of the device and by the tips of the movable feathers of the capacitive sensor 5, and the maximum capacitance recording unit B generates a serviceability signal. If, at any voltage jump, the instrument's hands do not reach the midpoint of the corresponding scale mark, then the maximum capacitance is not observed between the arrow and the tips of the movable feathers of the capacitive sensor 5 and no health signal is generated at the output of the maximum capacity register block b.

In the proposed device eliminated dynamic errors, which increases the reliability of the result of the video.

Claims (2)

Invention Formula A device for calibrating electrical measuring instruments containing a source of a reference signal, a capacitive sensor and a maximum capacity recording unit, while the tips of the movable pens of a capacitive sensor are placed on the protective glass of the device and aligned with the midpoints of the calibrated scale marks, and the output of the maximum capacitive sensor Capacities, characterized in that, in order to simplify and increase the verification verification accuracy, it has introduced an alternating tolerance voltage source and an adder, and regular enrollment of the reference signal and the alternating voltage tolerance coupled to corresponding inputs i of the adder, and the last output - with output lines examined emogo device. 7 A Sources of information taken into account in the examination 1. Bezikovich A.Y. and others. Automation of electric measuring instruments calibration. L., 1976, p. 10-12. 2. USSR author's certificate 344380, cl. 6 01 R 35/00, 1972.