SU1656322A1 - Differential sensor of linear displacement - Google Patents

Abstract

The invention relates to a measurement technique, namely, devices for measuring linear displacements. The aim of the invention is to increase the reliability and accuracy of measurement by eliminating errors from the effect of non-identical blocks in two chains of the comparison element. The signals from the outputs of the displacement transducers are fed to the inputs of the respective amplifiers 3, 4, the outputs of which are connected to the inputs of the differential amplifier 10. The output of the source 5 of the reference voltage is connected to the second inputs of blocks 6, 7, the outputs of which are connected to the inputs of the comparison unit 8 which is the control output of the sensor, is connected to the first input of the memory unit 9, the second input of which is connected to the input of the differential amplifier 10, and the output is the measurement output of the sensor. Thus, the same signals are fed to the differential amplifier 10 as to the inputs of the subtracting units 6, 7. 1 il.

Description

at

AND

Och

ate

Och

CJ

you to

The invention relates to a measurement technique, namely, devices for measuring linear displacements.

The purpose of the invention is to increase the reliability and accuracy of the sensor measurement by eliminating the axis errors due to the nonidentity of the transmission coefficients of the blocks in two chains of the reference element.

The drawing shows a block diagram of the Proposed sensor.

The sensor contains two transducers 1.2 displacements, two amplifiers 3.4, a source 5 of the reference voltage, two blocks 6, 7 reading, block 8 comparison, block 9 of memory And the differential amplifier 10, the outputs are connected to the first inputs of blocks 6, 7 subtraction and with the inputs of the differential amplifier 10, the output of the source 5 of the reference voltage is connected to the second inputs of subtraction blocks 6.7, the outputs of which are connected to the inputs of the comparison unit 8, the output of which, being the control output of the sensor, the second entrance is soy It is connected to the output of the differential amplifier 10, and the output is the measurement output of the sensor.

Differential linear displacement sensor works as follows.

In the initial state, the distance from each of the displacement transducers to the object 11 is equal, while the signals at the outputs of the transducers 1, 2 are equal and, therefore, the outputs of the amplifiers 3, 4 are set to equal signals Uo. The same signal value must be set and fixed at the output of the source 5 of the reference voltage. When moving an object on axis 00, for example, to a displacement transducer 2, the distance between them decreases as much as it increases between object 11 and transducer 1. At the outputs of amplifiers 3. 4, Do + signals appear respectively (U + A Ui ) and U0 - (U + D U2), where L Ui, A U2 are movement conversion errors into an electrical signal, due, for example, to an inaccuracy of the surface of the object 11 or to the nonidentity of the characteristics of converters 1, 2 movements.

These signals are fed to the first inputs of the first and second blocks 6.7 of the subtraction, from the outputs of which the signals U + D Ui and U + + D U2 are fed to the inputs of block 8 comparison. If these signals differ from each other by an amount D U less than

given a certain value d, then at the output of the comparison circuit there is a high voltage level which, acting on the first inputs of memory block 9, leads to

entering information arriving at its second input from the differential amplifier 10. Thus, at a high voltage level, the output of the comparison unit 8 at the outputs of the differential amplifier 10 contains signals Uo + (U + D Ui) and Uo - (U + D Ua ). and at its output - a signal equal to U0 + (U + D Ui) - Uo - (U + + AU2) 2 U + AUi -AU2 2, where is - D Ui - D U2 - an error predetermined

arbitrarily small value.

If the difference (U + D Ui) - (U + + D U2) exceeds the value of d, the output of the comparison unit 8 and the control output of the sensor show a low signal level,

which prohibits entry of information into the memory block 9 arriving at its first input. As a consequence, the output of memory block 9 and the measurement output will save the signal value that was present

before the arrival of a low voltage level at the second input of the memory block 9. A short-term low-level appearance at the control output indicates the presence of a single error, and its constant presence indicates a malfunction of the circuit elements of the transducers 1. 2 displacements or amplifiers 3, 4.

Thus, the inputs of the differential amplifier 10 receive the same signals as the first inputs of the subtractors.

Claims (1)

Invention Formula Differential linear displacement sensor containing two displacement transducers, first and second amplifiers, reference voltage source, first and second subtraction units, block comparison, a memory unit, with the outputs of the first and second displacement transducers associated respectively with the inputs of the first and second amplifiers, the outputs of which are connected respectively with the first the inputs of the subtraction units, the second inputs of which are connected to the voltage source, the outputs of the subtraction units are connected to the inputs of the comparator unit, the output of which, being the control output of the sensor, is connected to the first input of the memory unit, characterized in that measuring accuracy, it is equipped with a differential amplifier, the outputs of the amplifiers are connected with the inputs of a differential amplifier, a memory unit whose output is the output of which is connected to the second input by the measuring output of the sensor.