SU1126884A1 - Meter of electric values (its versions) - Google Patents

Abstract

The invention relates to measuring instruments and can be used to encode information represented by the conductivity of resistor or quasi resistor objects (sensors). The purpose of the invention is to increase the accuracy, speed and reliability of measurements achieved by obtaining a simpler proportional relationship between conductivity and scale coordinate. ly, as well as increasing the composition of the measuring circuit. The device contains a power supply 1, a voltage divider 2, a zero-organ 3, a resistor-measure 4, an additionally introduced dependent source 5 of power, a resistor-sensor 6, terminals 7-13.The device’s measuring circuit can be connected to a computer, for input corrections for tolerance and non-linearity of scale resistors. The device is promising for implementation (L in the form of precision conductivity meters. 1 Il.

Description

one .

The invention relates to electrical measuring equipment and can be used to encode information represented by the conductivity of resistor or quasi resistor objects (sensors).

The purpose of the invention is to increase the speed, accuracy and reliability of measurements by obtaining a simpler and more convenient, directly proportional dependence between conductivity and: coordinate: scales and minimizing the composition of the measuring circuit. The drawing shows the structures. The diagram of the conductivity meter.

The device contains a power supply 1, a voltage divider 2, a null organ 3, a resistor-measure 4, a dependent source-5, a resistor-sensor 6, terminals 7-13. At the same time, the first terminals of the input and output of the dependent source 5 are connected to terminal 7, the first output of power supply 1 and the first output of divider 2 voltage 5 are connected to terminal 8 The second output of voltage divider 2 is connected to terminal 9, the second output of power supply 1, the first the output of the resistor-measure 4, the second output of the input of the dependent source 5, to the terminal 10 are connected the second output of the output of the dependent source 5, the second output of the resistor-measure 4, the first output of the zero-organ 3, the second output of which is connected to the terminal 13 of the voltage divider 2, connected with glue Mami 11-12. A resistor sensor is connected between terminals 7 and 8.

The device works as follows.

After connecting the resistor-sensor 6 with the conductivity G at the last dependent source 5, by changing the current I of its output creates a voltage drop

(one)

GX E,

whereby a current is established at the input of the dependent source.

(2)

ul 0.

Somewhat later, by controlling the divider 2, the zero-body 3 sets a zero current at its input, which at the scale resistor-measure 4 creates a voltage drop IR and realizes the equality

1 /: B88LIR SHE,

(3;

where U is the coordinate of the unit,

R is the resistance of the resistor-measure 4.

After substituting expression (1) into expression (3) and transforming, we obtain

fbI: G ,;

(four)

 ( five)

IWR To obtain the numerical value of the measurement result G, it is necessary to substitute the numerical value R in Ohm in expression (5), i.e.

GX | U-R Ohm p. cm, (6)

where R cMj is the scale of the scale.

With sufficient sensitivity of the null organ and the dependent source, the error of the measurement result (coding) of the conductivity G is equal to the sum of the errors of the division factor of the divider Ln and the resistance error of the scale resistor Sn, namely

Gx (u R

(7)

Since in practice it is possible to fulfill the inequality

  R 7

(eight)

then in reality, the error of the device will be diminished to the level of error used in its 40 composition resistor, namely

 R;

(9)

4.5 which is (n-1) times less than in any n-shoulder bridge with an error in the execution of each arm at the level of &

Reducing the number of components affecting the quality and appearance of the scale,

50 affects not only precision, but also increase in reliability.

The measuring circuit of the device can be used in combination with the .jjj microcomputer to enter corrections for the tolerance and non-linearity of the scale resistors.

Thus, the device is promising for implementation in

Claims (1)

Claim A conductivity meter containing a power source connected in parallel with a voltage divider, 10 adjustable output of which is connected ^: to the first output of the zero-organ, a resistor measure and terminals for connecting a resistor-sensor of the measured conductivity, characterized in that 15, in order to improve performance, accuracy and reliability of measurements by obtaining a simpler and more convenient directly proportional dependent type between the conductivity and coordinate of the scale and minimizing the composition of the measuring circuit, it is equipped with a dependent source while the terminals for connecting the resistor-sensor are connected between the connection terminal of the first terminals of the input and output of the dependent source and the terminal connection of the first terminal of the power source and the additional output of the voltage divider, the resistor measure is connected between the terminal of the connection of the second terminals of the input of the dependent source, power source and the main output of the voltage divider and a clamp connecting the second terminals of the output of the dependent source and zero-organ.