SU809073A1 - Device for measuring value of current - Google Patents

Description

(54) DEVICE TO CONTROL THE VALUE CURRENT

The invention relates to automation and can be used in automatic control systems. A device for controlling the DC current is known, which contains a bias current source, a gating pulse generator, a differential current generator, the output of which is connected to the first input of the threshold element 1. However, this device has insufficient control efficiency, low reliability and low accuracy. The closest in technical essence is a device for monitoring the DC current, containing a bias current source, a gating pulse generator, a differential current generator, the output of which is connected to the first input of the threshold element, a base element, a switch, a reset pulse generator, triggers, a pulse shaper , the inverter, the key and the elements And, the first input of the first element And is connected to the first input of the first trigger and the output of the threshold element, the second input with the first output of the first trigger, ne the input of the second element I and through the reset pulse generator with the first input of the threshold element, and the output with the first input of the trigger, the output of the gating pulse generator is connected to the first input of the third element I, and through the inverter to the second input of the second element I and the input of the differential current generator and through the pulse shaper to the second inputs of the first and second triggers, the second output of the first trigger is connected to the second input of the third element And, the first and second inputs of the key are connected respectively to the input of the The output and output of the second element are And, and the output through the scale element with the second input of the threshold element, the third input of which is connected to the output of the switch, the outputs of the bias current source and the third element And are connected respectively to the first and second inputs of the switch 2. The disadvantage of the known device is complexity and low reliability resulting from the presence of a large amount of equipment. The current source of the mixing, differential generator and differential current to achieve the required accuracy of the device must have a sufficiently high stability, which leads to an increase in their size and decrease in reliability.

In known devices, the probability of leaving the threshold element as a result of a strong overload inside the gating pulse is preserved, which reduces their reliability.

The purpose of the invention is to simplify the device and increase the reliability of its operation.

This goal is achieved by the fact that a serially connected counter and a decoder, the output of which is an output of the device and connected to the control input of the switch, is entered into a device for controlling the magnitude of the current, containing a gating pulse generator and serially connected switchboard, the output The input of which is a device input, the output of the threshold element is connected to the clock input of the counter, the setup input of which is connected to the output of the generator and the strobe pulses.

The drawing shows the functional diagram of the device.

The device contains a switch 1, a scale element 2, a threshold element 3, a gate pulse generator 4, a counter 5 and a decoder 6.

The device works as follows.

The generator 4 generates a short pulse arriving at the input R of the counter 5 and setting it to the zero state (00). As a result of this code being decrypted by the decoder 6, its output 1 is excited, which switches the switch to position I.

In this state, the device monitors if the input current exceeds the lower limit.

t -ML ± JL-, hx.mir, -

where la is the current of the tunnel diode; C-voltage peak volt-ampere

diode characteristics. If the input current is IBX. exceeds the lower limit 1. element 3 is triggered and unit is written to counter 5. As a result, decoder 6 excites the second output, and the switch switches to the AND position, and the upper limit is monitored

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l y - -: HCG

When the switch switches from position I to position II, a short-term interruption of the circuit of the measured current occurs, as a result of which the operating point of the tunnel diode moves to the first upstream branch, which helps turn off the threshold element.

If the input current Igx exceeds Igx-oax, element 3 triggers again, unit 1 is written to counter 5, decipheror 6 triggers output 4, and the switch is set to position III. In this position, the device signals that the upper limit is exceeded by the current and controls that it does not exceed the alarm value.

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Similarly, the device is triggered in the case of IBX 1 in. Aver. The switch switches to position IV, and the controlled current circuit is broken. The input current can be judged by the code on the meter outputs or by the number of the decoder bus excited

The proposed device does not require a large amount of equipment for its construction, as a result of which it possesses increased reliability.

The use of a high-speed binary counter makes it possible to significantly reduce the duration of the pulse generated by the gating pulse generator and, therefore, shorten the time during KOTopojo threshold element 3 is in an overload state, while the probability of an exit from the tunnel diode is much less than 0 in known devices. In addition, the result of the control is stored at the outputs of the counter and in the pauses between the gating pulses.

Claims (2)

1. USSR author's certificate number 242500, cl. G 05 B 1/01, 1968. 2. USSR author's certificate for application number 2631443, cl. G 05 B 1/01, 1978.