SU384076A1 - DEVICE FOR MEASURING THE CONDUCTIVITY OF THE ELECTROCHEMICALLY CONTROLLED RESISTOR OF THE PASSIVE FOUR-POLES PASSIVE - Google Patents

Description

one

The invention relates to the field of instrumentation and can be used to measure and record the parameters of the output circuits of electrochemically controlled resistors, which are based on a reversible electrochemical system.

Devices are known for measuring the conductivity of an electrochemically controlled resistor — a passive two-port network — containing a controlled reversing unit, limiter units, voltage stabilization, conversion of the measured value into an electrical signal, a terminal recorder, and a coupling transformer.

However, such devices include two identical channels, each of which includes a DC voltage regulator, a modulator, a transformer, a demodulator, and a control circuit. In this case, the second channel is introduced into the device to compensate for the no-load current of the first stabilizer flowing through the recording device when the output circuit of the electrochemically controlled resistor is open, as well as to eliminate the influence of the mains voltage and the ambient temperature. The presence of the second channel in the device doubles the power consumption not only in the operating mode, but also in the idle mode. Independent operation of both channels

It imposes very strict requirements on the identity of the thermal stability of the channels in general and on the instabilities of the voltage of the network of constant voltage stabilizers in particular, which greatly complicates the configuration of the device.

The purpose of the invention is to simplify the design of the device.

This is achieved by connecting the input of the terminal recorder to the secondary winding of the coupling transformer via a demodulator and a reference measuring resistor.

The drawing shows a block diagram of the proposed device for measuring the conductivity of an electrochemically controlled resistor - a passive quadrupole.

The device contains a controlled reversing unit /, the maximum-minimum limiter 2 of the conductivity of the resistive electrode 3 of the electrochemically controlled resistor 4, the unit 5 of stabilizing the alternating voltage at the output terminals of the resistor 4, the terminal recorder 6.

The alternating voltage stabilization unit 5 includes a constant voltage regulator 7, the output of which is connected to the modulator 8. The feedback circuit of the stabilizer 7 is connected to the resistive electrode 3 via the demodulator 9 of the feedback circuit. A coupling transformer 10 is connected to the output of the modulator 8, the secondary winding // of which is connected via the reference measuring resistor 12 and the demodulator / J to the input of the terminal recorder 6. The resistor 12 and the demodulator li form a circuit for converting the measured value into a DC signal .

The controlled reversing unit / contains the control current reversal circuit 14 and the control current source 15, which is connected to the control circuit of the electrochemically controlled resistor through the reverse circuit 14 and the ballast balancing resistor 16, the resistance value of which is much greater than the resistance of the resistive electrode 3.

The proposed device works in the following way.

The constant voltage of the stabilizer 7, modulated by the modulator 8, through the coupling transformer 10 is supplied to the resistor electrode 3 and the reference measuring resistor 12. From the measuring resistor, the signal through the demodulator 13 is fed to the final recorder 6, like the recording device of the magnetoelectric system. To stabilize the amplitude of the alternating voltage applied to the resistive electrode 3, a demodulator is inserted into the device, connected between the output terminals of the electrochemically controlled resistor 4 and the constant voltage regulator 7. The feedback circuit demodulator 9 supplies the resistive electrode 3 to the error signal amplifier (not shown) of the stabilizer 7 with a negative feedback signal, thereby maintaining the amplitude of the alternating voltage across the resistive electrode 3. The output signal of the device proportional to the conductivity is controlled electrochemically of the resistor, through the maximum and minimum limiter 2 is also fed to the circuit 14 reverse control current. In the process of passing the control circuit when the conductivity of the resistor 4 reaches the maximum or minimum setpoint, the limiter 2 outputs a signal to the reverse circuit 14, which reverses the control current specified by the source 15. The resistor 16 is designed to balance the control current relative to the resistive length electrode.

The alternating voltage f / nsM on the measuring resistor 12 is determined by the current of the resistive electrode 3.

C / ism fiRmu - t YjcKi

"

where Um is the amplitude of the alternating voltage applied to the terminals

the resistive electrode 5 of the electrochemically controlled resistor 4;

UH is the conductivity of the resistive electrode 5 of the electrochemically controlled resistor;

RX is the value of the reference measuring resistance of the resistor 12.

It follows that the constant voltage UK, fixed by the terminal recorder 6, when the amplitude of the alternating voltage Um is constant, resistive electrode 3 is uniquely determined by the conductivity of the latter

x - ASU

where / Ci is a constant coefficient

demodulator transmission

(5) voltage from the measuring resistance to the recording instrument;

/ (UmRn3f.iK.i is a constant coefficient.

Conversely, the conductivity of the CL of the resistive electrode 3 at a constant amplitude of the alternating voltage Um on its terminals is determined at any time by the reading U of the terminal recorder 6

w.and ,.

Thus, when measuring the conductance of an electrochemically controlled AC resistor with the proposed device, there is no need for an additional channel, and, consequently, the efficiency of operation increases, power consumption is reduced, the device design, its setup and implementation are simplified.

Subject invention

A device for measuring the conductivity of an electrochemically controlled resistor — a passive quadrupole, containing a controlled reversing unit, limiter units, voltage stabilization, converting the measured quantity into an electrical signal, a terminal recorder and a coupling transformer, characterized in that

In order to simplify the device circuit, the input of the terminal recorder is connected to the secondary winding of the coupling transformer via a demodulator and a reference measuring resistor.