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Fisher™ 646 Electro-Pneumatic Transducer
Fisher 646 Transducer
The Fisher 646 electro-pneumatic transducer uses a converter module that converts a 4 to 20 milliampere input signal to a proportional 0.
2 to 1.0 bar (3 to 15 psig) pneumatic output signal. The converter module uses small parts of minimum mass, which are balanced symmetrically around a pivot point at the center of the mass. This balanced arrangement results in a high performance instrument that reduces sensitivity to vibration.
Fisher™ 646 Electro-Pneumatic Transducer


Area Classification
Explosion Proof, Intrinsically Safe, Non-incendive, General Purpose, Flame Proof
CSA, FM, ATEX, IECEx, CUTR, Regional
Communication Protocol
4-20mA Analog
Data Interface
Input Signal
Max Outlet Pressure
20 psig
Mounting Type
Remote Mount, Actuator Mount
Operating Temperature
Standard Temperature
Position Control
Modulating Control
Power Source
Supply Media
Other Configurations
Contact your local Emerson business partner or sales office to learn about additional specifications or options for this product.


  • The small size and light-weight design of the transducer facilitate mounting and provide improved space utilization.
  • The transducer, used in a standard valve/actuator mounted application, exhibits an output shift of less than 1 percent of span when tested to SAMA Standard PMC 31.1, Condition 3.
  • The output volume of the transducer is adequate to drive valve/actuator combinations without requiring a positioner or volume booster.
  • The transducer has low air consumption, which lowers operating costs.
  • Modular design of the converter allows easy replacement in the field for reduced maintenance costs.
  • The accuracy, linearity, and frequency response coupled with minimal hysteresis far exceed the requirements of most control systems.


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