Strain gauge measuring circuit

Strain gauge measurement circuit. ADT 70 is not only used for RTD/PRTD signal conditioning, but also can be used for
signal conditioning of bridge sensors, as shown in the figure is the strain gauge measurement circuit .
    The strain gauge sensor is driven by ADT 70 constant current. When the sensor detects a signal, its resistance value changes and the output
voltage changes. This voltage is directly added to the two input terminals of the instrument amplifier, and is output from the @ pin after amplification, and then The operational
amplifier performs a second amplification and outputs from the ◎ pin after amplification. The gain of the first-stage amplifier is determined by RG, and
the gain of the second-stage amplifier is determined by Rz/Ri, so the total gain of the amplifier is G=(49.9/Rc)(R2/Rl)