Fisher 3720 Electro-Pneumatic Positioner

Technical Specifications

Model：3720 Brand：Fisher Product Type: Electro-pneumatic rotary valve positioner

Module Feature

Fisher 3720 is electro-pneumatic positioner built based on 3710 pneumatic positioner with integrated 3722 I/P converter. It receives 4-20mA DC control signal and converts to pneumatic output for rotary valve actuator. It supports single acting and double acting configuration, direct/reverse action switch. Spool valve design provides fast response and high positioning accuracy. Widely used in oil,gas,chemical and power plant rotary control valves. Working principle: Electro-pneumatic conversion + spool valve feedback Onboard components:3722 I/P converter,spool valve assembly,feedback cam,gaskets,pressure gauge ports

LED indicators

Not equipped

Hardware self-diagnosis

Supply air pressure inspection,zero & span calibration,rotary stroke test,air tightness leakage test

Programming software

No dedicated software required

Pneumatic & Electrical Parameters

Input signal:4~20mA DC Supply air:20~150psi Application:Rotary diaphragm and piston actuator

Mechanical & Structure

Mounting:Direct mount on rotary actuator Protection class:IP54

Environmental

Operating temperature:-40℃ ~ +85℃ Ambient humidity:5~95% non-condensing Certification:CE,ATEX,IECEx Status:Fisher 3700 series electro-pneumatic positioner

System compatibility

Compatible with Fisher rotary diaphragm/piston actuators and rotary control valves for industrial process control system.

Function

3720 is electro-pneumatic positioner manufactured by Fisher. It compares 4-20mA electric control signal with actual rotary valve position and adjusts actuator air pressure to eliminate position deviation. It can switch single/double acting easily for different actuator types. Spool valve structure features low dead band and stable control performance. It is widely used for modulating rotary control valve in process industry.

Installation

Follow lockout/tagout safety procedure before installation. Cut off instrument air and electric signal. Mount positioner on rotary actuator, connect instrument air tubing and 4-20mA signal cable. Perform zero and span calibration and full rotary stroke test. Restore air supply and run valve function inspection.

Interface

1/4"NPT pneumatic ports, electrical signal conduit port, pressure gauge ports, fixed mounting holes on 3720.

Diagnostic

Valve no rotation: No supply air or loss of 4-20mA control signal. Poor positioning accuracy: Zero/span drift or cam wear. Actuator air leak: Damaged gasket or loose tubing fitting.

Product Brief

3720 Fisher electro-pneumatic rotary valve positioner,used for industrial rotary control valve stroke positioning with 4-20mA input signal,electro-pneumatic valve positioner.