SU817607A1 - Insulation resistance testing device - Google Patents

Description

tviH reference resistors, resistors and relays, an analysis unit and a signaling unit are entered, the first and second resistors are connected between the second terminals of the reference resistors and the corresponding input of the resistance measuring unit, the relay coil is connected to the common bus and the fourth output of the control unit, the fifth, sixth and the seventh outputs of which are connected respectively to the first, second and third inputs of the analysis unit, the first output of which is connected to the second input of the control unit, the third input of which is connected to the input of the alarm unit and the second output of the analysis unit, the fourth input is connected to the first input of the control unit, the relay contacts are respectively connected in parallel to the corresponding resistors, and the analysis unit contains two AND elements, the NOT element, the OR element and a pulse counter, the first input of the analysis unit connected to the first input of the first element I, the second input of which is connected to the first input of the first element I, the second input of which is connected to the fourth input of the analysis unit and the input of the element NO, the output of which is connected to ne the second input of the second element I, the second input of which is connected to the second input of the analysis unit, the third input of which is connected to the installation input of the zero pulse counter, the first output of which is connected to the first output of the analysis unit, the second output of which is connected to the second output of the pulse counter counting input which is connected to the output of the OR element, the first and second inputs of which are connected to the outputs of the first and second elements, respectively. The drawing shows a block diagram of the device. The device contains a unit 1 measuring either resistance, co) 5th transient threshold element 2, current control element 3 and resistors 4-6, a switching unit of self-tuning circuits 7, reference resistors 8 .1. . , 8К, 8.К + -fl, ... 8.m, resistors 9 and 10, control block 11, block 12, recording the result of the control, block 13 of analysis, containing element 14 NOT, elements 15 16 AND, element 17 OR and a pulse counter 18, an alarm unit 19, a relay 20 with make contacts 21 and 22 ,. a switching unit 23 of monitored circuits and a controllable memory unit 24. The device works as follows. The device operates in four cycles: the tuning cycle of the resistance measurement unit 1, two cycles of checking the correctness of the device self-tuning and the monitoring cycle of the circuits of the control object 25. During the first clock cycle, the switching unit 7 of the self-tuning circuits connects the necessary reference resistor, for example 8.1, and the corresponding resistor 9 to the inputs b; the resistance measurement loop 1, which is a bridge, the threshold element 2 is inserted into the measuring diagonal of the arms - current control element 3 connected to controllable memory block 24. Code change control unit 11 in control memory block 24, and, consequently, resistance value of current controlling element 3 begins to balance the bridge of block 1 and Resistance Measurements. At the moment of bridge balance, the threshold element 2 outputs to the control unit 11 a signal for the end of the tuning cycle of the resistance measurement unit 1. In the second cycle, the control unit 11 zeroes the counter 18 pulses of the analysis unit 13 and outputs a pulse to one of the inputs of element 16 I. If the device did not fail during the self-tuning, resulting in tuning to an overestimated level of control, or the contact of the self-tuning circuit 7 was broken , then at the output of the threshold element 2 there is a signal of logical 1, which is inverted by element 14 NOT, therefore the pulse from control unit 11 does not pass to the input of pulse counter 18. If during the adjustment, a malfunction occurred and the device tuned in, but not. the contact of the switching unit 7 of the self-tuning circuits is broken, then at the output of the threshold element 2 there is a logical signal O, the pulse from the control unit 11 goes through the element 16 AND and the element 17 OR to the counting input of the pulse counter 18. The signal from the first output of the pulse counter 18 is fed to the input of the control unit 11 and causes the device to re-configure the device by re-conducting the first clock cycle. If, after repeated self-tuning, when the second cycle is repeated, a pulse arrives at the counting input of the pulse counter 18, the signal from the second output of the pulse counter 18 goes to the alarm unit 19 and the control unit 11 and causes the test to stop. In the absence of a fault leading to a higher level setting, the device proceeds to the third cycle, during which the control unit 11 switches on the relay 20, which short-circuits the resistors 9 and 10 with its closing contacts 21 and 22, and issues a pulse to the element 15 I. If the device fails, resulting in

If the resistance measurement unit 1 is at a lower control level, then the output of the threshold element 2 is a logic 1 signal, which allows a pulse from block 11. control through the element 15 AND and the element 17 OR pass to the counting input of the counter 18 pulses. During the third cycle, a bad contact of the switching unit 7 of the self-tuning circuits is also detected. In this case, the device is adjusted to a control level much higher than the resistance value of the reference resistor 8.1. The magnitude of the resistor 9, several orders of magnitude smaller than the reference resistor 8.1 and only slightly higher than the dead zone at the level corresponding to this reference resistor 8.1, is less than the dead zone corresponding to the control level when the contact of the switching unit 7 of the self-tuning circuit is broken, therefore during the third cycle the output of the threshold element 2 is a logical signal 1 and the pulse from the control unit 11 is supplied through the element 15 AND and the element 17 OR to the counting input of the counter 18 named Pulse.

If, when the first three clock cycles are performed once or twice, the counting input of counter 18 does not receive a pulse more than one pulse, the pulse counter 18 will zero and the fourth clock will begin.

The switching circuit 23 of the monitored circuits connects alternately, in accordance with the test program, the control circuits (not shown) of the control object 25. If the resistance of the monitored circuit exceeds the tuning level of the resistance measurement unit, then the output of the threshold element 2 is a signal of logic 1. The control unit 11 supplies the recording result monitoring unit to the fixation result unit 12. When healthy monitored circuits are connected, the fourth clock cycle is repeated several times until the end of monitoring all switching circuits, or until the next periodic check of the correctness of the device setup and operability, or until it detects a defective monitored circuit. In the latter case, the correctness of the device setup is verified by conducting the second and third cycles. If the setting is correct and the device is working properly, the monitored circuit is monitored again and the result of the second control is fixed by the control result fixing unit 12. If the setting is downed, the first three cycles are carried out and, with proper self-tuning, the controlled circuit is also monitored again. If

the device is faulty, then after two first three cycles, the testing process stops and the alarm unit 19 calls the service personnel.

For periodic self-tests, the second and third cycles are conducted. If the result of the self-test is positive, then the control process continues. If the result is negative, then the first three bars are performed and,

o | with proper self-tuning, repetition; but all monitored circuits monitored after the previous self-test or, if the device fails, are monitored

5 is terminated. After testing all the monitored circuits of this level, the resistance measurement unit 1 is set up according to another reference resistor, for example .8 and a self-test control

0 all controlled circuits of this level. The process of self-tuning, self-checking and monitoring of the controlled circuits of the object 25 of the control, continues until the end of the control of the last controlled circuit, after which the device again runs a self-test. With a positive result of the last self-test, the test ends, about which a special signal may be given. The use of the proposed device allows a significant increase in the reliability of the control, as a result of which the probability of failures, malfunctions and

5 accidents at monitoring sites due to unprotected controlled circuits with reduced insulation resistance and reduced time lost in searching for faults in the test object and re-testing

0 due to the rejection of suitable controlled circuits, especially when testing complex control objects under a complex program.

45

Claims (2)

1. Isolation resistance monitoring device comprising a switching unit of monitored circuits, a controlled memory unit, a monitoring result fixation unit, a control unit, a self-tuning circuit switching unit, reference resistors, a resistance measuring unit, the corresponding inputs of which are connected to the first and second outputs switching unit of controlled circuits, the first output of which is connected to the output of the switching unit of self-tuning circuits, the input of the rejection level setting of the resistance measuring unit is connected to the output controlled memory unit whose input is connected to the first output of the control unit, the second output of which is connected to the first input of the fixation unit of the monitoring result, the second input of which is connected to the corresponding output of the resistance measuring unit and to the first input of the control unit, the third output of which is connected with the control input of the switching unit of self-tuning circuits, the inputs of which are connected to the first terminals of the reference resistors, resistors and relays, characterized in that, in order to improve the reliability of the control, An analysis unit and an alarm unit are installed, the resistors are connected between the second terminals of the reference resistors and the corresponding input of the resistance measuring unit, the relay coil is connected to the common bus and the fourth. The output of the control unit, the fifth, sixth and seventh outputs of which are connected respectively to the first, second and the third inputs of the analysis unit, the first output of which is connected to the second input of the control unit, the third input of which is connected to the input of the signaling unit and the second output of the analysis unit whose fourth input is Connected to the first input of the control unit, the closing relay contacts are respectively connected in parallel to the corresponding resistors. 2. The device according to claim 1, that the analysis unit contains two elements AND, the element NOT, the element OR, and a pulse counter, the first input of the analysis unit connected to the first input of the first element AND, the second input of which is connected to the fourth the input of the analysis unit and the input element NO, the output of which is connected to the first input of the second element I, the second input of which is connected to the second input of the analysis unit, the third input of which is connected to the input of the zero setting of the pulse counter, the first output of which is connected to the first output of the AN block Aliza, the second output of which is connected to the second output of the pulse counter, the counting input of which is connected to the output of the OR element, the first and second inputs of which are connected to the outputs of the first and second elements, respectively. Sources of information taken into account in the examination 1. USSR author's certificate 345453, class G 01 R 31/02, 1969. 2. USSR author's certificate number 221824, cl. G 01 R 27/02, 1966 (prototype).