Fisher Type 546 I/P Electro Pneumatic Transducer
The Fisher 546 transducer receives a direct‐current
input signal and use a torque motor, nozzle‐flapper,
and pneumatic relay to convert the signal to a
proportional pneumatic output signal. Nozzle
pressure, which operates the relay, is also piped to the
torque motor feedback bellows. This provides a
comparison between input signal and nozzle pressure
and reduces errors in nozzle pressure.