Accurate, Fast Response—3710 and 3720 positioners use field-proven spool valve technology for a simple design that gives accurate, fast-responding operation with high cycle life. These positioners are able to withstand the severe vibrations of most plant environments.
Modular Construction—The 3710 positioner converts easily to a 3720 positioner by adding the 3722 electro-pneumatic converter. The converter mounts over the instrument and supply ports in the 3710 positioner base. This provides a simple, compact, and cost-effective field conversion from pneumatic to electro-pneumatic valve positioning.
Corrosion-Resistant Construction with Air Purge—Case, components, and gasket materials withstand harsh environments. Proven engineered resins and 300 Series stainless steel construction is used throughout each unit. Die castings are low copper aluminum alloy to maximize corrosion resistance. Positioner bleed air purges internal positioner parts. As an option with some Fisher actuators, bleed air also purges the actuator housing for additional protection.
Extended Temperature Capability—With EPDM O-rings and input module diaphragm, 3710 and 3720 positioners can be used in low-temperature applications. With fluorocarbon O-rings and input module diaphragm, 3710 positioners can be used in high-temperature applications.
Meets Special Application Requirements— 3710 and 3720 positioners with fluorocarbon or EPDM O-rings and input module diaphragm can be used in applications with special material requirements as in the food and beverage industry, pharmaceuticals, and tobacco processing.
Easy Positioner Adjustments—With the cover removed, all internal components are easily accessed. Zero and span adjustments are made by hand with no tools required.
Stable Operation—Changes in supply pressure and ambient temperature have minimal effect on positioner operation.
Control Valve Diagnostic Testing Capability—To support diagnostic testing of valve/actuator/positioner packages, connectors, piping, and other hardware can be installed between the 3710 positioner and the actuator.
Valve Position Indicator—Standard, low-profile indicator or optional, beacon-style indicator mount easily to the positioner cover. 