SU1398096A1 - Capacitive displacement-to-code converter - Google Patents

Abstract

The invention relates to a measurement technique and is intended to automate the measurement and control of linear movements. The aim of the invention is to increase the speed of the converter. To do this, a capacitive displacement transducer to a code containing a generator of I pulses, diodes 4 and 5, capacitive sensor 6, resistors 8 and 9, low-pass filter 10, RS flip-flop 12, counter 13, digital-to-analog converter 15, comparator 11, electronic key 2 and register I5, a reference capacitor 7, an inverting repeater 16, a non-inverting repeater 17, and an electronic switch 3 are introduced. The goal is achieved by converting the code into one period of the pulses of the generator I of pulses. 1 il.

Description

l

00

with

00

about with about

The invention relates to an emulsion technology of flax technology and is intended to automate the measurement and control of linear displacements,

The purpose of the invention is to increase the speed of the converter.

In the drawing. There is a page diagram of a capacitive displacement transducer,

The capacitive converter of the transducer into the code contains the generator named after the pulses, the electronic switches 2 and 3, the isolating elements made on the diodes 4 and 5, the capacitive sensor 6, the driver of the reference signal made on the capacitor 7, the current limiting elements made on resistors 8 and 9, filter 10 lower Hjjx frequencies, comparator 1 I, memory element, executed on RS flip-flop 12, counter 13, register 14, digital and analogue converter 15, non-sig- nating 16 and inverting 17 inverters and reference source 18.

The capacitive displacement transducer to the code works as follows.

In the initial state, a negative voltage level is set at the output of the comparator 11, corresponding to the logic level O, the inverse output of the RS flip-flop 12 - level 1, setting the counter (3 to the initial state. The output of the digital-analog converter 15 of the repeaters 16 and 17, the voltage from - (; becomes unhealthy. When a pulse is released to the S-input of the RS flip-flop 12 via the input bus at the inverse output of the RS-. Trigger 12, the level 0 is set and the counter starts filling with 13 pulses of the generator 1,

The outputs of the digital-to-analog converter 15 and the repeater 16 form stepwise increasing positive polarity voltages, while the output of the repeater 17 produces stepwise increasing negative polarity voltages. At the same time, voltage pulses with a stepwise increasing amplitude of positive polarity are formed at the junction point of the diode and resistor 8, and the duration of the capacitance determined by the constant discharge time of the capacitive sensor 6 is generated at the junction point of the diode 5 and resistor 9. the increasing amplitude of the negative polarity and the duration of the decay, determined by the constant discharge time of the capacitor 7,

When the shoulders of the nonlinear bridge circuit are identical, the linearly increasing output voltage of the low-pass filter 10 is proportional to the capacitance difference between sensor 6 and capacitor 7. The comparator I1 switches at the instant of equality of the linearly increasing voltage at the output of the filter 10 and the reference voltage Vo at the source 18 output. this, at the output of the comparator 11, sets a positive polarity voltage level corresponding to level 1, which translates into register 14 a digital code at the outputs of the counter 13, corresponding to moment equality of voltages on the inputs of the comparator 1 1. Simultaneously, the level 1 is fed to R-input of RS-flip-flop 12, setting it to its original state. Level 1, appearing on the inverted output of RS flip-flop 12, sets the counter 13 also to its initial state. A new conversion cycle starts with the arrival of the next trigger pulse on the code pad.

With an optimal capacitance of capacitor 7 compensating the constant parasitic component of capacitive sensor 6, a digital code is written to register 14, and the output of digital-to-analog converter 15 is formed in the process of converting a stepwise increasing voltage with an amplitude linearly dependent on displacement.

Claims (1)

Invention Formula A capacitive displacement transducer to a code containing a pulse generator, the first output of which is connected to a counter input of the counter, the outputs of which are connected to the register, whose outputs are transducer outputs, the first electronic switch, the output of which is connected through a first separating element to a capacitive sensor and the input of the first current-limiting element, the output of which is connected to the input of the low-frequency filter, a digital-to-analog converter, the second current-limiting element, the second separator th element, comparator, memory element, characterized in that, in order to increase the speed of the converter, a reference voltage source, a non-inverting repeater, an inverting repeater, a second electronic key, a reference signal driver, the counter outputs, are connected to the DF inputs of the Rope Analog Converter, are entered into it, the output of which is connected via a non-inverting repeater to the information input of the first electronic key, and through the inverter a repeater to the information input of the second electronic key yucha whose output is connected through a second divider the element with the input of the reference signal generator, the output of which is connected via the second current-limiting element to the input of the low-frequency filter, the output of which is connected to the first input of the comparator, the second input of which is connected to the reference voltage source, and the output is connected to the input of the register entry and the first input of the element memory, the second input of which is the converter start input, and the output is connected to the zero setting input, the second and the third the outputs of the pulse generator are connected to the control inputs of a variety of first and second electronic keys. Compiled by E, Budarina Editor P. Gereshi Tehred A. Kravchuk Order 2608/57 Circulation 928 VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Corrector S.Cherni Subscription