SU1325292A1 - Displacement measuring device - Google Patents

Abstract

The invention relates to a measurement technique and can be used to measure displacements. The goal — an increase in accuracy and an extension of the dynamic range — is achieved by eliminating the loss of information at the moments of the connection to the common wire of switch 2. I by inserting the second switch 2.2, memory block 6, and operational amplifier 9, which allows for the following operating mode devices with memorization of the measuring signal at the moments of switching keys 2.1 and 2.2. This also eliminates jumps in the output voltage at switching times. 1 il. (L 1,, with p with o o

Description

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

The purpose of the invention is to improve the measurement accuracy and expand the dynamic range by eliminating information loss at the moments of closing to the common wire of the two-position key and eliminating the output voltage jumps.

The drawing shows a block diagram of a device for measuring displacements.

The device comprises a pulse generator 1, a block 2 of on-off keys 2.1 and 2.2, an inverter 3, a key 4, the control input of which is connected via an inverter 3 to the output of the generator 1, a delay element 5, an analog memory block 6, the control input of which is connected to the output generator 1 through the delay element 5, the source 7 of the reference voltage, the adder 8, the operational amplifier 9, the integrator 10 connected at the output of the adder, and the capacitive primary converter 11.

The device works as follows.

Generator 1 generates square-shaped pulses with a ratio of Q 1.1–1.2 (attenuation coefficient “J., 83–0.91). These pulses are fed to the control input of the block 2 of two-position keys 2.1 and 2.2. In the time interval when a logical unit is formed at the output of generator 1, the source of the key 7 of the reference voltage is sent to the output of the key 2.1, and the output of the second key 2.2 receives the signal of opposite sign from the output of the memory block 6, whose amplitude is generally different from the amplitude signal source 7 reference voltage. As a result, two symmetrical in time and opposite in sign signal are formed at the outputs of these switches, respectively, coming to the first and second inputs of the capacitive primary converter 11. The opposite plates of the capacitors Cx and Co of the converter 11 are combined, due to which the voltage drops on them.

The output signal from the converter 11 is fed to the inverting input of the operational amplifier 9, from the output of which through the memory block 6 and the key 2.2 of the key block 2, the signal goes to the second input of the converter 11 to which the reference capacitor Co is connected. The negative feedback circuit formed by blocks 6 and 9 tends to nullify the output voltage of the converter 11 when the switch 4 is open, which is controlled from the generator 1 through the inverter 3.

In the time interval when the logical zero signal is generated at the output of the generator 1, the outputs of the two-position keys 2.1 and 2.2 are connected to the housing and the key 4 is closed. In this case, the memory block b goes into the memory mode, since the delay element 5 is not. delays the negative pulse front (transition from “1 to“ O).

In the transition signal at the output of the generator 1 from a logical zero to a logical

At one unit, the signal at the output of amplifier 9 cannot change abruptly, since the amplifier has a limited rate of rise of the output voltage. Therefore, unit 6 goes into tracking mode not immediately at the moment of switching the two-position keys 2.1 and 2.2, but after some time equal to the rise time of the output voltage of the amplifier 9. At the same time, the output signal of the delay element 5 when the signal at its input from the logical unit

0 to a logical zero is not delayed, and when the latter transitions from a logical zero to a logical one, it is delayed by a time equal to the rise time of the output voltage of the amplifier 9. This eliminates bursts of the signal at the output of the block 6. Thus, the voltage at the output of the key 2.2 constantly monitors the change in the capacitance Cx of the variable capacitor of the displacement converter 11. The output signals of the source 7 of the reference voltage and of the block 6 are fed to the adder 8, the output of which is the voltage, the magnitude and sign of which depends on the change in capacitance Cx of the displacement converter 11 relative to the zero position, at which CxCo.

5 The output voltage of the adder 8 goes to the integrator 10, which averages it.

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Claims (1)

Invention Formula A device for measuring displacements containing a capacitive primary transducer, a pulse generator, a reference voltage source, the first two-position switch, an output connected to The first input of the converter, the key, the delay element and the integrator, characterized in that, in order to increase the accuracy of measurement and expansion of the dynamic range, it is provided with a second two-position key integrated with the first key into one block, the control input of which is connected to the generator input. , an output connected to the second input of the converter, an operational amplifier, the output of which is connected via Q. with its inverting input, which is connected to the output of the converter, with an inverter connected between the generator output and the control input of the key, an analog memory unit whose input is under 1325292. about 4 keys to the output of the op amp, neither and the input of the first two-position and the control input is connected via an ele-key, the second input is connected to the output A delayed delay with an output of a generator, and a sum-analog memory block and an input by a secondator, the first input of which is connected to an on-off key, and the output of the output source of the reference key is directly connected to the integrator's input.