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.

  • 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.

646  Bulletin  Instruction Manual