Isolated 4 to 20mA-RTD transmission amplifier circuit

The isolated 4~20mA-RTD transmission amplifier circuit is shown in the figure. The function of this circuit is to
convert the sensor output signal into a 4-20mA current , then convert it into a voltage and then isolate the output.
XTR101 is a 4~20mA current transmitter (will be introduced in detail in the next section). The temperature signal detected by the RTD temperature sensor
is processed internally by XTR101 and outputs a 4-20mA current. This current passes through VD and forms a voltage on the roar. This voltage
is the input signal of differential amplifier IC2 (gain is 1). The output of 1C2 is sent to IS0120 for isolation amplification and then the output is an isolated
signal v0.