SU1663397A2 - Displacement-to-phase transducer - Google Patents

Abstract

The invention relates to instrumentation technology and can be used to measure the movement of objects. The purpose of the invention is to improve the accuracy by correcting the phase of the reference signal at the phase meter input. A phase-shifting unit and limiter amplifiers are introduced into the converter, which makes it possible to correct the zero-level offset of the output characteristic of the sensing element by changing the phase of the reference signal that occurs during manufacturing or long-term operation, as well as when the temperature affects the components of the converter and the sensor. 1 hp f-ly, 4 ill.

Description

The invention relates to an instrumentation technique and can be used to measure the movement of objects.

The purpose of the invention is to improve the accuracy by correcting the phase of the reference signal at the phase meter input.

FIG. 1 is a block diagram of a converter; in fig. 2 - vector diagram of the output signals; in fig. 3 and 4 are graphical dependences of the output characteristics, respectively, of the sensitive element and the displacement transducer — phase in the displacement function.

The displacement transducer — the phase contains a sensing element 1, which includes a ferromagnetic measles 2, mounted for movement, and a balancing ferromagnetic plate 3, sections 4, 5 of the field winding, electrically connected in series according to section 6, 7 of the measuring winding, electrically connected in series oppositely core 8; block 9

increase the reliability of the measured movement, which includes keys 10, 11, the reference phase-shifting unit 12, the control unit 13, the control bus 14, as well as the sinusoidal voltage generator 15, the reference signal phase correction unit 16, limiting amplifiers 17, 18, a phase meter 19, having in its composition an output stage 20 of a voltage gain of a direct current, a converter sensitivity control unit 21. Parallel to section 7 of the measuring winding, a phase-shifting element 22 is connected, for which a resistor is chosen, which in combination with the inductance of the measuring winding is a phase shifter.

The Converter operates as follows.

When the field winding (sections 4, 5) is connected to the sinusoidal voltage source 15 in sections 6, 7 of the measuring winding, the irab and Uon are energized, respectively. Using a phase-shifting circuit (parallel to

AND

ABOUT

ON CJ GO

VU VI

to

the connected inductance of the measuring winding section 7 and the element 22) the phase of the sinusoidal voltage Don is shifted relative to the sinusoidal voltage 1) the slave is at an angle $ e more than 90 ° but less than 180 °. The voltages 1) slave and Uon are geometrically summed over sections 6, 7, and the resulting signal Ur and the reference signal Uon through the key 11 and the block 16 for correcting the phase of the reference signal are fed to the inputs of the limiter amplifiers 17.18, respectively, from whose outputs the signals Uj- and Uon are supplied respectively to the signal inputs Bx.1 and Bx.2 of the phase meter 19, which records the phase difference between the signals Uj. and uon in the form of wiV dc voltage.

When moving the monitored object and the associated core 2 in the direction of increasing the gap, the voltage on the windings 6, 7 is modulated as a function of the movement 5P.

The voltage Upa6, excited in section 6, decreases, and the voltage Uon, excited in section 7, increases,

The conversion function is defined by

pry - # 2

sin tj) o

 arctg

, Crab QO

cos u c vv h

Uon {xi

where pvs is the phase of the resulting sum signal Ur relative to the voltage vector Uon,

B is the phase angle between the voltage vectors Upa6 (x) and Uon (x).

When modulating voltages Upa6 (x) and Uon (x) change on sections 6, 7 of the measuring winding, the value and phase of the total (resulting) signal changes by ((%) as a vector diagram) sensor output signals (Fig. 2). At which the voltages corresponding to the maximum gap of 5PMA are indicated by a stroke, and without it, the voltages corresponding to the minimum gap,

Ornin.

When measuring movements in the operating mode, there is no control signal on bus 14, a control signal appears at the inverse output of block 13, which is fed to the control input of key 11 and opens it. From the direct output of block 13, the signal enters the input of the key 10 and closes it. The total sinusoidal voltage J2 from the output of sections 6, 7 of the measuring winding is fed to the input of the first amplifier limiter 17, and the reference sinusoidal voltage Uon is through the public key 11 and the block 16 is fed to the input

amplifier limiter 18.

From the outputs of the limiting amplifiers 17, 18, the signals U and U0n arrive at the inputs of the phase meter 19, which records the change in the phase of the total signal as a function

0 displacement (pits f (dp) at its inputs as a change in DC voltage as a function of displacement.

Improving the measurement accuracy by introducing the unit 16 for correcting the phase of the reference voltage Uon and the unit 21 for adjusting the sensitivity of the converter is illustrated in FIG. 3 and 4, where the continuous line shows the output characteristic of the sensitive element f0p), taken 0 when calibrating the sensor in the manufacturing process with recording the calibration results at the output of the phase meter 19 in the form of a direct current voltage wiwi f (5p) and. documenting the results

5 graduations in sensor formulas.

During operation of the sensor, due to the time instability of the component parts of the sensing element of the transformer sensor and temperature effects, the zero value of the output characteristic of the sensitive element f (5p) can be displaced (in Fig. 3 is shown by dashed lines) parallel to the output characteristic of phase 5 when calibrating (depicted in FIG. 3 by a solid line), which leads to a decrease in the accuracy of movement measurement.

To avoid zero displacement, the output characteristic of the sensor using block 16, which is an adjustable phase shifter, smoothly shifts the phase of the reference signal Uon at input Bx of phase meter 19, against which the resulting signal phase is measured, so that the output characteristic of the sensitive element approximates and coincides with the output characteristic shown in FIG. 3 solid line.

0 As a result of the correction of the zero offset of the output characteristic of the sensitive element, the zero offset of the output characteristic of the converter recorded by the phase meter 19 is eliminated,

5 In addition to shifting the zero output characteristic of the sensor, due to temporal instability and destabilization of factors (temperature, etc.) of the component parts of the sensing element 1. of block 9 for increasing the reliability of information of the measured displacement and phase meter 19 during operation, the sensitivity of the sensor conversion changes (in Fig. 4, the output the characteristics are shown as dashed lines), i.e., the accuracy of the measurement of displacements decreases.

In order to avoid changing the sensitivity of the sensor conversion using the sensitivity control unit 21 connected between the output and the input of the output stage 20 of the voltage gain of the phase meter, the sensitivity of the phase meter conversion 19 is changed smoothly before measuring during operation using the block 21 the resulting change in the sensitivity of the sensor due to the effect of the sensor, the influence of destabilizing factors and the temporal instability of the parameters with converter parts, i.e., the accuracy of the displacement measurement is improved.

Claims (2)

Claim 1. Transducer displacement - phase according to ed. St. No. 1562675, which differs from the fact that, in order to increase accuracy, a phase correction block of the reference signal and two limiter amplifiers are introduced into it, the first extreme terminal of the measuring winding is connected to the first signal input of the phasemeter via the first limiting amplifier, the moving unit and the first switch are connected in series through the phase correction unit of the reference signal and the second limiting amplifier connected to the second signal input of the phase meter. 2. The converter according to claim 2, in which the sensitivity adjustment unit is inserted into it, and the phase meter output is connected to the phase meter control input through the sensitivity adjustment unit. Uprf ch graa vLrftft) fig.Z FIG. 2 BUT (ffp) I  JP Op, (M CAR: f (Sp) fig L up, pl.