SU1446502A1 - Device for measuring pressure with frequency output - Google Patents

Abstract

The invention relates to a measurement technique and makes it possible to increase the accuracy of pressure measurement. For this, the output voltage of the generator 2 is supplied to the primary winding of the Differential-transformer converter 1, from the secondary winding of the converter 1 the voltage through the amplifier 3, the active detector 4 and the filter 6 is fed to the first input of the adder 10 and through the divider 8 to the second input of the adder 11. At the same time, the voltage from the generator 2 through the active detector 5 and the filter 7 is fed to the first input of the adder 11 and through the divider 9 to the second input of the adder 10. From the outputs of the adders 10 and 11, the voltage goes to the input of the converter 12 voltage relation, and from the output of the converter 12 through a band-pass filter 13 - to the device output. 1 il. and S (L

Description

4 F SP

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The invention relates to a measurement technique and can be used to measure pressure.

The aim of the invention is to improve the accuracy of pressure measurement.

The drawing shows a block diagram of the device.

The device contains a differential-transformer pressure converter 1 Q, a low-frequency current generator 2, an amplifier 3, active detectors 4 and 5, filters 6 and 7, two dividers R8 and R9j, adders 10 and 11, a voltage ratio converter 12 and a band-pass filter 13 .

The device works as follows.

The output voltage of the generator 2 is supplied to the primary winding differential 14 6

-

15

20

Potential-transformer converter 1, creating a voltage drop Uj on it. From the secondary, the winding of the Converter 1 is removed for

As can be seen from formula (5), the dependence of the frequency fgj, the output signal on the measured parameter (pressure P) is a fractional function, independent of the supply voltage U of the primary winding of the differential transformer converter. This pressure dependence P allows automatic correction of the non-linearity of the differential transformer converter. At the same time, its sensitivity increases with increasing pressure,

Ho and, associated with .growth Ug through 25, the changer should also increase,

transfer coefficient of the differential transformer converter f (p):

and, f (p) -Uo. (one)

to compensate for this increase and, conversely, with decreasing sensitivity, the denominator must be reduced, which is achieved by

Q

f to 51o (el.

  PIU 1

(five)

4 65022

rhc is the ratio of the voltage to frequency converter.

-Subscribed, in the formula (4) expressions (2) and (3) and taking into account the damping (1), we get

+ Kj

K, (pJ

As can be seen from formula (5), the dependence of the frequency fgj, of the output signal on the measured parameter (pressure P) is a fractional function, independent of the voltage U of the supply voltage of the primary winding of the differential transformer converter. This pressure dependence P allows automatic correction of the non-linearity of the differential transformer converter. At the same time, if the sensitivity of the converter increases with increasing pressure,

15

20

25 menyah also should increase

in order to compensate for this increase and, conversely, with decreasing sensitivity, the denominator must be reduced, which is achieved by choice.

Through the amplifier 3, the first active 30 magnitude and the sign of the coefficient K ,. The detector 4 and the first filter 6 is the voltage multiplied by the resulting coefficient of transmission of the path K, is fed to the first input of the adder 10, to the second input of which through 35 the second active detector 5, the second filter 7 and the divider R9 receive the voltage multiplied by the division factor K divider R9.

Thus, at the output of the summer 40, a voltage U is formed equal to

Ui K., and, + K, and .. (2)

Similarly, the output of the adder 11 forms a voltage of, 45 equal to

and Uo + K.-Kj-U ,; (3) where Kg is the division factor of the divider R8.

Both voltages are fed to the input of a 12 ratio converter voltage with a research institute that converts the ratio of these voltages into a frequency

50

By setting the value of the K coefficient, the slope of the transducer is required, and by adjusting the K coefficient, the initial frequency of the output signal in the absence of an input signal.

By reducing the frequency of the current supplying the primary winding of the differential transformer converter, energy losses in the magnetic circuit are reduced and the temperature component of the error is reduced.

Thus, as a result of all the measures listed above, it is possible to significantly improve the accuracy of pressure sensors.

Claims (1)

Invention Formula A device for measuring pressure with a frequency output, containing a differential transformer generator, a voltage-to-frequency converter, and a power source, characterized in that, in order to improve the accuracy of pressure measurement, the frequency converter contains a sinusoidal x-frequency current generator, amplifier two active detectors  K U bn pnch and / (four) f & (. 1X output frequency of the comparator and bandpass filter magnitude and sign of the coefficient K ,. You By setting the value of the K coefficient, the slope of the transducer is required, and by adjusting the K coefficient, the initial frequency of the output signal in the absence of an input signal. By reducing the frequency of the current supplying the primary winding of the differential transformer converter, energy losses in the magnetic circuit are reduced and the temperature component of the error is reduced. Thus, as a result of all the measures listed above, it is possible to significantly improve the accuracy of pressure sensors. Invention Formula A device for measuring pressure with a frequency output, containing a differential transformer generator, a voltage-to-frequency converter, and a power source, characterized in that, in order to improve the accuracy of pressure measurement, the frequency converter contains a sinusoidal x-frequency current generator, amplifier two active detectors 31.446502 two filters, two dividers, two summators, the output of the generator is connected to the cheatator, the ratio converter cuts the second active detector and the second voltage and bandpass filter, with a filter with the second input of the second sum, the output of the generator is connected to the permrator and through a divider to the second The primary winding of the differential input of the first adder, the output of the transformer converter, the second adder is connected to the first input of the secondary winding by the differential home converter of the transformer transformer ratio, the second input of which is connected to the output of the secondary converter, output Qchen to the output of the second adder, which is connected to the output of the second accumulator, output Qchen to the output of the second adder, connected to the output of the second accumulator, output Qchen to the output of the second adder, connected to the output of the second input the stroke of the ratio converter is the pressure and the first filter is connected to the first-arc and is connected to the input of the strip the input of the first adder and through the de-filter, the littel - with the first input of the second sum