SU1176255A1 - Method of measuring electric voltages - Google Patents

Abstract

) A METHOD FOR MEASURING ELECTRIC VOLTAGES, which consists in forming the first and second voltages, summing the voltage being measured with the first exemplary voltage, characterized in that, in order to improve the accuracy, the resulting amount is measured, the first and second are measured. model voltages, then find the differences of the first and second, as well as the third and second measurements, divide the first of these differences by the second, multiply by the difference of the second and first exemplary voltages, and judging by the result obtained led (For the measured voltage.

Description

1 The invention relates to electrical measuring equipment and can be used to measure constant voltage. The purpose of the invention is to improve the accuracy by eliminating the additive component of the measurement error. PA figi 1 presents a block diagram of the device for the implementation of the proposed method; in fig. 2 shows an example of a computing unit; in fig. 3 is an example of the execution of the control unit. The method is carried out as follows. Three measurements are performed sequentially. 1) The measured values are summed with the first exemplary measure N K (1+) (x + Xp) + 4, (1) where N is the measurement result; K - meter transmission coefficient; V is the multiplicative measurement error (transmission coefficient instability X is the measurable value; XQ is the first exemplary measure; is the additive measurement error (drift zero). 2) The first exemplary measure NI K is measured (1 + G where N is the measurement result. 3) The second sample measure N3 K (1 +) x + D is measured, (3) where Nj is the measurement result; X. - second sample -mera-, To estimate the measured value, the ratio is calculated. N-, - NZ-X h L3 Nl 1 - oh After the substitution of expressions 1-3 in expression (4), it can be verified that the result of the calculation does not depend on either additive or multiplicative measurement errors. Device for the implementation of the pre. The labeled method (Fig. 1) contains a switch 1, the input of which is the device input, and the output is connected to the first input of the adder 52 2, the output of which through the voltage-to-voltage converter 3 is connected to the first input of the computing unit 4, the first output of which is device output, the second output through the converter 5 code to voltage is connected to the second input of the adder 2, the third output is connected to the input of the control unit 6, the first output of which is connected to the control input of the switch 1, the second output to the input starting the converter .3, and the third output - to the second input of the computing unit 4.; Input unit 4 (Fig. 2) contains memory registers 7-9, the inputs of which are connected to the first input of block 4, inverters 10, the inputs of which are connected to the outputs of register 8, and the outputs - to the first inputs of adders 11: 12, the second inputs which are connected respectively to the outputs of registers 7 and 9, and the outputs respectively to the first and second inputs of the divider 13, the shaper 14 of a constant coefficient, the output of which is connected to the first input of the multiplier 15, to the first input of which the output of the divider 13 is connected, the output of which forms the first output block a 4, a pulse generator 16, the output of which is connected to the input of the distributor 17 of pulses, the first output of which is connected to the control input of the register 7, the second output to the control input of the register 8, the third output to the control input of the register 9, the fourth output , to the control inputs of the summers 11 and 12, the fifth output to the control input of the divider 13, the sixth output, to the control input of the multiplier 15, the outputs are shaped. 18 and 19 reference codes are connected to the switch inputs 20, the control input of which is the input of block 4, and the output of the second output of block 4, and the OR 21 element, the first, second and third inputs of which are connected respectively to the first, second and third the outputs of the distributor 17, and the output forms the third output of the block 4 ... The control unit 6 (FIG. 3) comprises a pulse generator 22, the output of which is connected to one input

And 23, to another input of which the input of block 6 is connected, and to the output - input of the distributor 24 pulses, the first output of which forms the first output of block 6 and is connected to the first input of the OR 25 element, the second output is connected to the second input of the OR 25 element, and the third output forms the third output of block 6 and is connected to the third input of the SHSh 25 element, the output of which forms the second, the output of block 6.

The device works in the following way. -.

In the first cycle of operation of the device, the control unit 6 at the command of the computing unit A closes the contact of the switch 1 and gives the command to the unit 4 to form the NQ code. The code formed at the second output of block 4 is converted into a voltage signal UQ by means of a converter 5. At the output of the adder 2, a voltage signal Ux + is generated. At the command of block 6, converter 3 generates an N code corresponding to the signal and + Up. On the next command of block 6, code N is memorized by block 4,

In the second cycle, block 6 opens the contact of switch 1. At the output of adder 2, a voltage signal U (j, is generated by the commands of block 6 and is converted into code N2 and remembered by block 4.

In the third cycle, block 6 commands the block 4 to generate the NOJ code. The NQJ code is converted to the voltage by means of the converter 5. The voltage through the adder 2 is fed to the input of the converter 2 and is converted by the block 6 command to the NJ code,

In the fourth cycle of operation of the device, block 4, using the formula (4), calculates the NX code corresponding to the value of the measured voltage U, forms Nj (at the output of the device, and gives block 6 a signal that the measurement has ended. After that, the described process is repeated.

The device eliminates the additive and multiplicative components of the error of the voltage converter 3 in a code with an accuracy determined by the accuracy of the voltage converter 5 of the code.

Computing unit 4 works: in the following way.

The pulse from the first output of the pulse distributor 17, which can be implemented, for example, in the form of a shift register, the result of the first measurement N from the output of the converter 3 is stored in register 7. The pulse from the second output of the distributor 17 is the result of the second measurement N-stored in register 8 By a pulse from the third output of the distributor 17, the result of the third dimension N, is stored in register 9, the Nj Code, stored in register 8, is inverted by a set of inverters 10, the number of which is determined by the number of bits 3. photoelectret pulse output from the fourth distributor 17, the adders 11 and 12 are determined respectively amounts N. + (- N) and NJ + (- NJ), which is the ratio of the momentum of the fifth to exit the distributor 17 determines a divider 13

/ Ni - nz h „

(------). The result of dividing cleverly

(x 0 - multiplier 15 according to the signal from the sixth output of the distributor 17. Former 14 of the constant coefficient can be, for example, a set of switches. Signals from the first, second, third outputs of the distributor 17 through the OR 21 element allow the control unit 6 Formers of reference codes 18 and 19 can be implemented, for example, on sets of switches and form codes corresponding to the first and second exemplary measures.

Ho N, X;

X N LH

where 4 is the quantization step of the converter 5.

The switch 20 codes connects the codes to the input of the converter 5 according to the signal from the control unit 6.

The control unit 6 operates in the following way.

The signal from the computing unit 4 permits the passage of clock pulses from the generator 22 through the element I 23 to the distributor 24. The pulse from the first output of the distributor 24 gives a command to close

switch 1 (the first measurement cycle) and through the OR element 25 starts the converter 3. The signal from the second output of the distributor 24 through the element OR 25 starts the converter 3 (the second measurement cycle). In this case, the single position switch 1 is already disabled. The signal from the third output of the distributor 24

gives a command to the computing unit 4 to switch the switch 20 and starts the converter 3 through the element OR 25 (third measurement cycle). The code of the first exemplary measure under: the keys to the input of the transducers 5 during the entire time except the third measurement cycle.

L

22

byk one

four

ow / x.5

Bta.t

25

Claims (1)

(57.) METHOD FOR MEASURING ELECTRICAL VOLTAGES, which consists in generating the first and second reference voltages, summing up the measured voltage with the first exemplary, differing in that, in order to improve accuracy, they measure the resulting sum, measure the first and the second reference voltage, then find the differences of the first and second, as well as the third and second measurement results, divide the first of these differences by the second, multiply by the difference of the second _c and the first model voltages, and judge the result by S value of the measured voltage.