SU1673997A1 - Device for measuring infralow frequency voltage - Google Patents

Abstract

The invention relates to an infra-low frequency voltage meter. The purpose of the invention is to reduce the measurement time of the infra-low voltage. The device contains the source 9 of the reference voltage, voltage divider 10, controllable keys 3, 5, 11, 13, integrators 4, 12, analog storage cells 6, 14, discrete voltage divider 15, comparing unit 16, decoder 17, digital the indicator 18 and the key 19. The input signal is processed by the scale 1 and measuring 2 converters, and then using the listed elements, the mean or average direct voltage value of the alternating voltage is measured over half the period. 1 il.

Description

The invention relates to an infra-low frequency voltage meter and can be used as an element of an object control system, the movement of which occurs at an infra-low frequency, as well as in the study, adjustment and adjustment of automatic control systems and their individual components.

The purpose of the invention is to reduce the duration of the infra-low frequency voltage measurement.

The drawing shows a block diagram of the device.

The device contains a scale converter 1, a measuring converter 2, a first control key 3, an integrator 4, a second control key 5, an analog storage cell (AZN) b, a time interval allocating unit 7, a control unit 8 (CU), a reference source 9 (ION), voltage divider 10, third controllable key 11, additional integrator 12, fourth control key 13, additional analogue storage cell AZYa 14, discrete voltage divider 15 (RDS), comparing unit (SB) 16 , decoder 17, digital indicator Op 18, Key 19.

Scale transducer 1 is designed to select the desired measurement range. Transmitter 2 is a rectifier. Using key 19, the measuring transducer 2 is connected or disconnected, as a result of which the device readings are proportional to the average wired or average voltage value, respectively. Voltage divider 10 serves to select the desired frequency range of the voltage to be measured. The time interval allocating unit 7, fixing the moments of transition of the measured voltage through zero, forms short pulses at the input of the control unit 8 with a period equal to the period of the measured voltage. The device works as follows.

In the initial state, the scale converter 1 and the voltage divider 10 are set in accordance with the selected frequency and range of the measured voltage. Key 19 is closed if it is necessary to measure the average value of the voltage and open if it is necessary to measure the reference value. All controllable keys 3, 5, 11, 13 are open, integrators 4, 12, analog storage cells 6, 14 are reset to zero from the outputs of control unit 8.

When a measured voltage arrives at the input of the device at the time it passes through a zero value by a time interval allocator 7, a pulse of the beginning of the period is generated, which enters control unit 8, which opens controllable keys 3, 5, 11, 13. From this point in time, the integrators 4 and 12 begin to integrate the incoming voltages. The integrator 4 integrates the voltage coming from the output of the measuring transducer 2 or the large-scale converter 1 and at the end of period T at the output of the integrator 4 will be

voltage t

U / U (t) dt

(D

0

0

0

with key closed 19 or

(t) | dt (2)

about

with the key open 19.

The input of the integrator 12 receives the voltage generated by the source 9

a com base voltage 9 and a voltage divider 10, and the output of the integrator 12 at the end of the period will be voltage 0

U- /, (3)

about 1hd1hd

Uo is the reference voltage of source 9;

Kd is the division factor of divider 10, which is proportional to the period of the measured voltage.

The voltage from the output of the integrator 4 through the public key 5 enters the analog storage cell 6, and from the output of the integrator 12 via the key 13 into the analog storage cell 14.

At the end of the period, block 7 generates a pulse arriving at control block 8, which closes the keys 3,5,11, 13, zeroes the integrators 4, 12, opens the keys 3, 5 and starts controlling the discrete voltage divider 15 as commanded by the comparative block 16 In this case, one input of the comparison unit 16 will be supplied with voltage from АЗЯ 14, which is defined by expression (3), and the other input is supplied with voltage

five

Ui ir- / ЩО dt

Lpp „

or

U2

NPV about

1 t

Chad about

/ MOJdt,

(four)

where KDD is the division factor of the discrete voltage divider 15.

In this case, the CU 8 will change the division ratio Cdd of the discrete voltage divider 15 until the equality is fulfilled:

one

NPV

/ U (,)

OR

/ -} iu (t) ldt

dd d

(five)

When the equalities (5) are fulfilled, BU 8 zeroes AZN b and 14 and opens keys 5 and 13

From expressions (5), it follows that the division factor Cdd is directly proportional to the mean or average direct value of the measured voltage over a period, i.e .:

 IT (U (t) dt or / U-O dt (6)

The state of the discrete voltage divider, i.e. the KDD value, is indicated by a decoder 17 on the digital indicator 18 as a decimal number.

Thus, the device makes it possible to determine the average or average permeable value of the infrared voltage of low frequency in one period.

Claims (1)

Invention Formula A device for measuring the voltage of an infra-low frequency, containing a scale converter, the input of which is connected to the input terminal and the output - to the input of the measuring converter, the output of which through the first control key is connected to the input of the integrator, the output of which through the second control key is connected to the analog input memory cell, the control unit, the first input of which is connected to the input terminal through the time slot allocation unit, the first output of the control unit is connected to the 5th control input of the first control key, the second output of the control unit is connected to the integrator zero input and the control input of the second control key, the third output of the control unit 0 is connected to the zero memory input of the analog memory cell, characterized in that, in order to reduce the measurement time, the reference voltage source, voltage divider 5, third and fourth controlled keys, second integrator and analog memory cell, discrete divider, comparing the block, the decoder, the digital indicator and the key, the output of the reference voltage source being connected via a voltage divider to the input of the third controlled key, the output of which is connected to the input of the second integrato ra, the output of which through the fourth controlled 5 the key is connected to the input of the second analog storage cell, the output of which is connected to the first input of the comparison unit, the second input of which is connected to the output of the first analog storage cell through the discrete voltage divider, to the first output of The control input of the third control key is connected, 5, the zero output of the second integrator and the control input of the fourth control key are connected to the second output of the control unit, the third output of the control unit is connected to the zero input of the second analog storage cell, the fourth output of the control unit is connected to the control input of the discrete voltage divider, information output which through the decoder is connected to 5 digital input indicator.