mv to 10V current voltage conversion circuit diagram

circuit function

The analog signal interface has always used a 4~20MA current loop in the past. 4MA is 0% of the full scale and 20MA is 100% of the full scale. The current signal is converted into a voltage at the input end before signal processing. This circuit uses 12MA as a dual loop. The zero point of the pole converts the current of 4~20MA into the voltage of -10~+10V. This circuit can be used as the interface of the DC servo motor circuit or the converter for the recorder.

How the circuit works

The purpose of using OP amplifier A1 is to consider that if one end of sensor resistor R1 cannot be grounded, it can be used as a differential amplifier. However, if the resistances R6 and R7 of the adder are high, AI can be lost. In order to make the output of A3 be -10V at 4MA, the output of A1 should be -2~-10V.

OP amplifier A2 is an adding amplifier that converts a unipolar input into a bipolar signal output. In order to make the output 0 at 12MA, +6V with opposite polarity is added for subtraction.

VR3 is used to determine the slope. Because the 8V input is to be amplified to 20V, the amplification factor should be A=20/8=2.5 times.