Fisher 846 Series Electro-Pneumatic Transducer
Fisher™ Model 846 translates an electrical output signal from a controller to a pneumatic signal that is required for the operation of a control valve actuator or pneumatic positioner. This transducer functions masterfully in vibration, thanks to its durable construction, mechanically-damped deflector bar and low-mass pilot stage. Its key electrical and mechanical components are integrated into a solitary field-replaceable master module.
The 846 features an electronic feedback control network that monitors the pneumatic output signal for input-output aberrations and makes corrections. Its free-flow pilot stage design, wide internal pneumatic supply passages and large diameter nozzles help minimize the consequences of contaminant build-up and erosion.
Stroke Port allows a continuous bleed from the pilot stage to escape via a hole in the module cover. The transducer output can be elevated by covering the hole, thus verifying the appropriate operation of the pilot and booster stages and stroking the actuator.