Fisher 3582i Electro-Pneumatic Positioner with 4-20mA for Diaphragm-Actuated Sliding-Stem Control Valves

Product Overview

The Fisher 3582i is an electro-pneumatic valve positioner that combines a 582i converter with a 3582 pneumatic positioner. It is built for diaphragm-actuated, sliding-stem control valves. The converter takes a 4-20 mA DC signal and turns it into a proportional pneumatic pressure through a nozzle/flapper mechanism. That pressure then drives the positioner stage, which adjusts actuator supply pressure to hold the valve stem where the input signal commands.

The unit provides accurate, fast response and tolerates vibration. Steady-state air consumption is low. Because the design is modular, a 582i converter can be added to an existing 3582 pneumatic positioner in the field to create a 3582i. Zero and span adjustments are made with a screwdriver and spanner after removing the cover. Direct and reverse action can be switched on site. Supply pressure and valve load changes have little effect on performance. The case and internal materials resist harsh conditions, and bleed air purges internal parts.

Technical Specifications

Application Industry

The 3582i is used in process industries that rely on diaphragm-actuated sliding-stem control valves. It handles flow, pressure, temperature, and level control. The adjustable zero and span range covers standard input signals, including split ranges. Because one positioner family supports many applications, spare parts inventory is simplified across the plant.

Common Problems

• Positioner does not respond to input signal: Check supply pressure and pneumatic connections. Verify that the nozzle/flapper assembly is not clogged and that the relay is functioning.

• Valve stem position does not match input signal: Check zero and span calibration. Verify that the cam position matches the actuator travel and action.

• Erratic operation or oscillation: Inspect for air leaks in tubing and fittings. Check for excessive friction in the valve packing or actuator.

• Supply pressure fluctuations affect position: Confirm supply pressure is stable and within the recommended range. The 3582i is designed to minimize the effect of supply pressure changes, but extreme fluctuations may still cause issues.

Replacement Models

The 3582i is a legacy pneumatic positioner design. For new installations requiring digital communication and diagnostics, the DVC6200 or DVC2000 digital valve controllers are the modern equivalents from the same product line. The 582i converter can be field-installed on an existing 3582 pneumatic positioner to upgrade it to a 3582i configuration, though this may require changing positioner mounting and input signal range. For cross-vendor alternatives, verify actuator mounting, travel range, and input signal compatibility before ordering.