SU1665220A1 - Displacement-to-electrical signal transducer - Google Patents

Abstract

The invention relates to a measurement technique and can be used to measure movement in an electrical signal. The purpose of the invention is to improve accuracy by reducing the influence of external factors. This is achieved by introducing an additional measurement winding offset from the main one by a known amount. When the device is operated in the indicated windings, a flow is induced depending on the coordinate location of the measurement coils and time according to exponential laws. At the same time, on the comparators connected to the read winding and to the main and auxiliary measurement windings, signals whose difference integrals are proportional to

one is of known magnitude, and the second is the X coordinate of the main measuring winding. By processing the received signals on the integrator blocks, an output pulse is obtained, the duration of which is proportional to X. 2 Il.

Description

The invention relates to measurement technology and can be used to measure displacements in automatic control systems.

The purpose of the invention is to improve accuracy by reducing the influence of external factors.

Figure 1 shows the structural diagram of the device; 2 shows timing diagrams for the operation of the device.

The device contains a transformer primary converter 1. The magnetic circuit of which is made consistent with excitation winding 2, measurement winding 3 consisting of a main 3.1 and an additional 3.2 windings, and

winding 4 readings, constant voltage source 5, keys 6-11, comparators 12-15, circuits AND 16-18, integrator units 19, 20, circuit NOT 21, differentiating chain 22, circuit OR 23, one-shot 24. Start terminal 25, resistors 26 and 27, capacitors 28 and 29. Parallel-connected switch 8, integrator 19 and capacitor 28 form the first integrator unit 30, the output of the parallel connection is the output of the unit, and the input through the resistor 26 is connected to the first input of the unit Key input 8 is the second input of the block. Similarly, the key 11, the integrator 20, the capacitance 29 and the resistor 27 form the second integrator unit 31.

Os O (L N GO O

A constant voltage source 5 is connected via a control key 6 to the excitation winding 2, with inverse inputs of the first, second and fourth comparators 12, 13, 15, through the first and second keys 7 and 9 - the inputs of the integrator units 30 and 31, respectively. The read winding 4, the main 3.1 and the additional 3.2 measuring windings are connected to the direct inputs of the comparators 12, T5, 13, respectively. The inverse output of the second comparator 13 and the direct output of the fourth comparator 15 are connected to the inputs of the first circuit AND 16, the output of which is connected to the control input of the first key 7. The inverse output of the fourth comparator 15 and the direct output of the first comparator 12 are connected to the inputs of the second circuit, the output which is connected to the control input of the second key 9. The inverse output of the first comparator 12 is connected to the control input of the third key 10 and to the first input of the third circuit AND 18. The output of the first integrator unit 30 is connected via the third key 10 to the inlet ohm second integrator unit 31, the output of which through the third comparator 14 is connected to the second input of the third circuit And 18, the output of which is through the circuit NOT 21 and differentiating chain 22 connected to the first input of the circuit OR 23. Terminal 25 Start (device input) is connected to the second input the OR circuit 23, the output of which is connected to the input of the one-shot 24. The direct output of the one-shot 24 is connected to the control inputs of the keys 8 and 11, the integrator blocks 30 and 31, respectively, and the inverse output to the control input of the control key 6. The device works as follows. After the arrival of the Start signal (Fig. 2, a), the one-shot 24 produces a voltage pulse of a fixed duration (Fig. 2, b). During this time, the key 6 opens, and the keys 8, 11 close, which leads to the discharge of the integrating capacitors of the integrator units 30 and 31. After the end of this pulse, the key 6 closes (Fig. 2c), as a result of which the excitation winding 2 an exponential current flows and a magnetic flux F is induced in the magnetic circuit, varying as a function of the X coordinate and time t

F (x, (1), (1) where m is a constant excitation winding time;

J (RMLMA) g coefficient. The voltages taken from the read and additional windings are equal to

U (x.t) -W - F (, L)

 -MFM1 / ge / ge x, where W is the number of turns in the windings.

(2)

If we accept the coordinate of the additional winding X0 0, the first section of the read winding X1 X, and the second X2 X + Z, where Z is the magnitude of the winding displacement, and, designating Tn rln (UM / E0n), KTJ, after simple mathematical transformations, the durations are obtained THEN, T1 and T2 pulses generated at the outputs of the comparators 12. 15 13 respectively

5TO G In (Umax / Eon) TH (3)

T1 Tn-g- j -X TH-K -X (4)

T2 - Tn - K (X + Z) (5)

0 (Fig. 2 g, d, e).

At the outputs of the circuits AND 16 and 17, pulses of duration (T1-T2) and (TO-T1), respectively, are formed (FIG. 2, h), which close the keys 7 and 9. As a result, at 5 outputs of the integrator blocks 30 31, wives (figure 2 and k)

C -T2

Ui -1 / Rc / Udt -1 / RcX

0 XU (T1 -T2) ° -1 / Rc -U K -Z

TO -t Ua - 1 / R with / U dt - 1 / R with X (6)

XU (TO-T1) - 1 / R with U K -X

 respectively. After the end of a pulse with a duration of maintenance, the signal from the inverse output of the first comparator 12 closes the switch 10, which causes the compensation of the voltage U2 by the voltage U1. At the moment when voltage is zero, U2 triggers the third comparator 14 and the equality is valid

U2- (1 / RC) U1TBb, x 0 (7)

From here your equal

TBb, x (RC / Z) -X (8)

(figure 2, l).

After the termination of the SWITCH pulse, a step-shaped voltage appears at the output of the HE-circuit 21, which, passing through

- differentiating chain 22, turns into a narrow pulse and starts a single vibrator 24. After this, the cycle of operation of the device is repeated.

Thus, the duration of the output pulse SWe, proportional to the coordinate X of the measuring winding, does not depend on the parameters of the magnetic circuit, and therefore does not depend on changes in the magnetic properties of the material due to external factors (temperature

radiation, etc.), which significantly reduces the additional errors of the device when measuring displacements.

Claims (1)

Invention Formula A device for converting a movement into an electrical signal containing a transformer primary transducer with excitation windings, sensing and main measuring windings placed on the magnetic core, a constant voltage source, a measuring signal processing unit whose direct input is connected to the main measuring winding, a key control, the information input of which is connected to the output of a DC voltage source, and the output - to the excitation winding, and the one-oscillator, the inverse output of which is connected chen to the control input of the control key, characterized in that. in order to increase accuracy, three similar keys, three comparators, two integrator units, three AND schemes, an OR circuit, a NOT scheme, a differentiating chain and an additional measurement winding placed on the magnetic core were introduced into it, the measuring signal processing unit was made as a fourth the comparator, the measurement windings are made identical and are shifted relative to each other by a predetermined value, the output of the DC voltage source is connected to the inverse inputs of the fourth, as well as the first and second comparators, direct in the strokes of which are connected to the outputs, respectively, of the reading and auxiliary windings, the inverse output of the second comparator and the direct output of the fourth comparator through the first circuit AND are connected to the control input of the first key, the inverse output of the fourth comparator and the direct output of the first comparator through the second circuit And connected to the control input of the second key, the inverse output of the first comparator is connected to the control input of the third key and the first input of the third And circuit, the inputs of the first and second keys are connected to the output meters of a constant voltage source, and outputs with the first inputs of the first and second integrator units, respectively, the output of the first integrator unit via the third key is connected to the input of the second integrator unit, the output of which is connected to the second input of the third circuit I The output of the device is connected through the NOT circuit and the differentiating chain is connected to the first input of the OR circuit, the second input of which is the input of the device, and the output is connected to the input of a one-shot, the direct output of which is Connected to the second inputs of integrator blocks. Zalusk Fj3 B dJ 1