SU1416991A1 - Device for input of data from differential transmitters - Google Patents

Abstract

The invention relates to the field of automation and computer technology and can be used to enter information into the system of automatic control and monitoring of technological processes. The aim of the invention is to increase the reliability of the input information. The device contains a sinusoidal voltage shaper 1, a sensor 2, a pagshti unit 3, an analog-digital converter 4, a delay element 5, a level 6 shaper, a strobe shaper 7. The purpose of the invention is achieved by forming a strobe controlling the conversion process at the point in time when the voltage of shaper 1 reaches a fixed value of E, thereby eliminating the effect of voltage instability of shaper 1 on the result of the conversion. I silt

Description

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with

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The invention relates to automation and computing, and is intended to enter information from differential 71 sensors into an automatic control and monitoring system for technological processes.

The purpose of the invention is to improve the accuracy of the input information.

The drawing shows a block diagram of the device.

The device comprises a sinusoidal voltage driver 1, a sensor 2, a sample-storage unit 3, an analog-flat converter (ADC) 4, a delay element 5, a level driver 6 and a gate driver 7.

The device works as follows.

Sensor 2 captures the corresponding parameter of the physical action X. The control input of sensor 2 from the imaging device I receives a sine-signal E EpSinwt .. At the output

sensor 2 depending on the value of X and the design parameters of the sensor y, i.e. In accordance with a certain function F (x, y), a signal (x, y) 51PIL is generated ,. coming on

3 memory block input. When a pulse from the output of the gate generator 6 arrives at the control input of the unit 3, the unit 3 switches to the storage mode. With this impulse, through the driver 6 and the delay element 5, the pulse is started.

ADC A.

The gate former 7 is a voltage comparator with a predetermined trigger threshold H EpSinus where t is the instant of the appearance of the leading front of the gate. At time 1, the voltage at the output of sensor 2 reaches an instantaneous value (x, for nsinwt HF (X, y). The strobe is formed from the signal E EpSinurfc, which comes to the n inputs of the rammer 7 and the sensor 2. Since constant when the amplitude deviates from the nominal value

. H arc sin EO

to

is changing

so that the instantaneous value of the amplitude of the signal at the output of sensor 2 at time 1 of occurrence of the leading edge of the strobe remains unchanged. In this way, a conversion error due to a change in the supply voltage is eliminated.

A specific implementation of the proposed technical solution will be considered by the example of an input device for information from an inductive ID-8 sensor, which is a differential magnetic displacement sensor. The physical quantity x acting on the sensor is the pressure of compressed air. Information on the change in the value of this pressure is fed to the automatic control system. The amplitude value of the output signal of the sensor with a sufficiently large load resistance is determined by the expression

Um

U) LO E oh

7v

one)

where EJJ is the amplitude value of the power supply voltage (E, 36 Bt6%);

circular frequency of the power source (Hz12%); inductance of the sensor half winding in the middle position of the core core; active resistance of the sensor winding; the air gap between the magnet cable and the sensor core is in the middle position; air gap increment with pressure change. Since the magnitude of the displacement

the sensor is proportional to the magnitude

pressure P, expression (l) takes

view

(J b g

with. BUT

{:

K (R-RS

(2)

where P is the pressure sensor corresponding to the average position of the sensor core;

K is a coefficient depending on the design parameters of the sensor, in particular, on the geometrical configuration and. core material cor.

From the expression (2) it follows that the amplitude value of the output signal of the sensor depends on the voltage and frequency of the power source, the magnitude of the measured pressure and the design

parameters (g, L

about

and does not depend on the change in voltage source

Claims (1)

Invention Formula A device for entering information from differential sensors containing a sinusoidal voltage driver, a sensor, an analog-digital converter, the output of a sinusoidal voltage generator is connected to the control input of the sensor, the output of the analog-digital converter is an information output device, different that, in order to improve the accuracy of the input information, it will introduce a gate driver, a memory block. a shaper and a delay element; the strobe input of the gate is connected to the sinusoidal voltage shaper output; the strobe shaper output is connected to the control input of the memory unit and the level shaper input, the output of which is connected to the A / D converter start input; with the information input of the block, the output of which is connected to the information input of the analog-digital converter.