Sensing signal measurement - 4 to 20mA current converter

The function of the circuit shown is to amplify the measurement signal of the sensor and convert it into a 4-20mA current output.
The measuring bridge is a bridge sensor, which can be a gas sensor or a pressure sensor; the excitation voltage of the sensor is
the IO. OOV reference voltage source of the AD694 itself (output from the ⑦ pin), and the sensor output signal is sent to the AD524 for amplification
The output is sent to the buffer amplifier inside AD694 ② and ③ pins. After buffer amplification, it is processed by the internal VI converter and other circuits , and finally outputs 4-20mA current
from ⑩ pin .