SU367545A1 - - Google Patents

Description

NOISE-RESISTANT INTEGRATING VOLTMETER

one

The invention relates to electrical measuring technique and may find application in measuring voltage of a steady current with imposing periodic hindrances.

Known noise-tolerant integrating voltmeters containing a game generator — a frequency – frequency, a converter’s impulse counter, a zero-time comparator of the time component of the voltage being measured, and an input time variable averager, including an Atom frequency generator, logic circuits “ And, included between the transducer and the counter, the generator of the reference frequency and the scaling circuit with a Tunable conversion factor, and a trimmer, whose single output is n To the control inputs of the circuits "And, the single input to the shunt terminal of the voltmeter, and the zero input to the output of the interchange circuit, have insufficient accuracy of measurement of the CONSTANT voltages with the applied variable components, the period of which is not an average of the input averaging time impact.

To eliminate this drawback, the proposed device introduces an "OR and lauz setter between the half-intervals of averaging each gauge containing the triggers, the AND circuit and a reversible counter, while the Zero input of the first lazer trigger is connected to the comparator output, the single output is connected to the control input of the first circuit AND connecting the generator of the exemplary frequency to the direct count input of the reversible counter. a, the single input via the second circuit I connect to the output of the counting circuit, and the bullet output of the nodes To the single input of the second trigger, the single output of which is connected to the control input of the third AND circuit, connecting the reiieparop of the reference frequency with the return input; the south counter of the reversing counter, the output of this counter, which generates it When the counter is detected, it is connected to the zero input of the second trigger, To the input of the third trigger, the single output of which is connected to the secondary input of the second circuit And, through the logic circuit dLlIi connected to the starting terminal of the voltmeter connected to single input ode to the third trigger.

FIG. 1 Iredstazlepa funktsio: 1naln scheme of the proposed volt. Meter; in fig. 2 shows time diagrams of his work.

The voltmeter contains a 1 converter / voltage-frequency and a comparator 2 zero values of the variable component of the measured voltage. Converter output

voltage-frequency is connected via logic circuit "I 3" with a 4-pulse counter.

The control inputs of the circuits And 5 and 5 are connected to a single output of trigger b, the single input of which is connected through the logic circuit OR 7 to the starting circuit of the voltmeter. The inputs of the circuit "And 5; 8 and 9 are connected to the generator 10 of the reference frequency, and the outputs are connected respectively to the conversion circuit 11c with a tunable conversion factor, the forward and reverse counting inputs of the reversing counter 12. The output of this counter is connected to the zero inputs of the trigger 13 and 14, as well as to the single input trigger 6 through the scheme “OR 7. The output of the reference circuit // is connected to the zero input of trigger 6, and through the scheme“ PI 15 to the single input of trigger 16.

The trigger 6, the circuits And 3 and 5, the reset circuit 11, and the generator 10 of exemplary frequency form the setpoint generator of the averaging intervals of the input action.

Triggers 13, 14 and 16, schemes “And 8; 9 and 15, the reversible counter 12 and the comparator 2, together with the generator of the exemplary frequency 10, form a pause setter between the averaging intervals.

The work of the proposed voltmeter proceeds as follows.

The pulse of the beginning of the measurement at the input “Iusk through the logic circuit” OR 7 gets to the input of the trigger 6, its transfer to the unit state. Thereby, the And 5 and 5 schemes are prepared for operation.

The pulses from the converter / voltage-frequency output go through the I: circuit: to counter 4, with the frequency of the pulses proportional to the level of the input action.

The output pulses of the generator 10 are received on the inputs of the circuits "And 5; 8 and 9, but passes only to the input of the scaling circuit. Through

R;

time - equal to half the required time

neither averaging, from the output of the scaling circuit 11 a pulse will arrive that will return the tritger 6 to the initial zero state and through the AND 15 circuit prepared for operation by the tritger 13 will arrive at the input of the trigger 16 transferring it to the unit state. The input to the input of the counter 4 pulses of the measured frequency of the frequency, and to the input of the counting circuit 11 pulses of the reference frequency is stopped.

Rejecting the trigger 16 into a single state prepares the IK for operation of an “AND 8” circuit, from the output of which the pulses of an exemplary frequency begin to arrive. To enter the direct counting of the reversing counter 12.

The closest IN time, starting from the moment the trigger 16 transitions to the single state, the pulse received from the output of the comparator 2 zero values of the Variable Controlled component, returns the named trigger to its initial state, stopping the arrival of the pulses of the reference frequency to the direct count input reversible counter 12. The residence time of the trigger 16 in a single state corresponds to the measured time interval Hz (see Fig. 2).

The impulses coming to the input of the reverse counting of the reversible counter 12 “previously write off the number BHecaiHoe to it. At the moment of resetting the counter 12, an impulse is removed from its output, which triggers the 13 vi 14 triggers to the initial zero state, and the trigger 6 to the single state. Again, from the transducer 1 — into the counter 4 I1M pulses, the pulses of the measured frequency begin to be put, and the pulse frequency of the reference frequency is inserted into the coding circuit 11.

The residence time of the trigger 14 in a single state is equal to the time Guy, and so, KaiK, the writing and reading of numbers in the counter 12 comes from one generator of the reference frequency.

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After a time, after the secondary transfer of the trigger 6 to the single state, it returns to the initial state. Measurement is over. If there is no interference at the input of the voltmeter, then the start of the second half-interval averaging is caused by resetting the counter 12 as a result of its overflow at the input of the direct count.

Object of the Invention Interference-resistant integrating voltmeter containing a voltage-frequency converter, a pulse counter of a converter, a comparator of zero values of the variable component of the measured VOLTAGE and a set generator of input action averaging time intervals, including an exemplary frequency generator, logical circuits connected between the converter and a counter, a generator of the reference frequency and a scaling circuit with a tunable (conversion efficiency factor, and a trigger, the output of which It is connected to the control inputs of the circuits And, the single input to the starting terminal of the voltmeter, and the zero input to the output of the conversion circuit, characterized in that, in order to increase the accuracy of measuring DC voltages with superimposed variables, the periods of which are not is a multiple of the averaging time of the input action; an OR circuit and a setpoint pause between half intervals of each measurement averaging are included in it, containing the triggers, the AND circuit and a reversible counter, the zero input of the first pause trigger trigger is connected to the output to The comparator unit output is connected to the control input of the first AND circuit, which connects an exemplary frequency generator to the direct count input of the reversible counter, the single input through the second AND circuit is connected to the output of the counting circuit, and the zero output is connected to the single input of the second trigger, single output of which is connected to the control

to the input of the third circuit "AND connecting the generator of the exemplary frequency input of the counting counter of the reversible counter, and the output of this counter, on which the signal is formed when the counter is reset, is connected to the zero input of the second trigger, to zero

the input of the third trigger, a single output of which is connected to to the control input of the second circuit "AND, and through the logic circuit" OR connected with the starting terminal of the voltmeter connected to the single input of the third trigger.

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