FISHER 3660 Pneumatic Single-Acting Valve Positioner

Overview

The FISHER 3660 is a pneumatic single-acting valve positioner under Emerson Fisher. It receives a standard pneumatic control signal and outputs air pressure to the actuator to position the sliding-stem control valve proportionally. Its counterpart model 3661 is the I/P version accepting 4–20 mA signal. This positioner is commonly matched with Fisher 657, 667, 1250, 1250R, 3024S, GX actuators and Baumann actuators for throttling control in process plantsEmerson.

Features

The FISHER 3660 delivers fast and accurate positioning and performs well under heavy plant vibration. Gain and damping are adjustable to stabilize loop response. It supports split-range operation, zero and span calibration can be completed without removing the cover. Most internal spare parts are interchangeable, lowering spare stock cost. It can be fitted with auxiliary piping for FlowScanner valve diagnostic testing. It complies with ATEX gas and dust hazardous area certificationEmerson.

Specs

Device Type: Pneumatic single-acting valve positioner Model: FISHER 3660 Brand: Fisher (Emerson) Signal Input: 3–15 psi (0.2–1.0 bar) or 6–30 psi (0.4–2.0 bar) pneumatic signal Supply Media: Instrument air Max Output Pressure: 90 psig (6.2 bar) Linearity: ±1% of span Stem Travel: Adjustable up to 20 mm, or 20–50 mm Proportional Band: 0.5 ~ 6% PB Mounting: Direct actuator mounting Certification: ATEX II 2G / II 2D Operating Temperature: Standard / high temperature option Related Model: 3661 = electro-pneumatic I/P positioner

Principle

The FISHER 3660 compares the incoming pneumatic setpoint signal with the valve stem feedback position. The flapper-nozzle amplifier adjusts output air pressure to the actuator. The actuator drives the valve stem until the feedback lever balances the signal difference, so the valve opening follows the pneumatic command signal.

Applications

The FISHER 3660 is widely used on control valves for oil & gas, chemical, power and water treatment, for flow, pressure, level and temperature modulating control. It is stocked as spare for maintenance and replacement of legacy pneumatic control loops.