3582i Electro-Pneumatic Positioner 4-20mA for Linear Pneumatic Single-Acting Actuators in Stainless Steel

Product Overview

The 3582i is an electro-pneumatic valve positioner built for diaphragm-actuated, sliding-stem control valve assemblies. It consists of a 582i electro-pneumatic converter installed on a 3582 pneumatic valve positioner. The converter receives a DC current input signal and produces a proportional pneumatic output through a nozzle/flapper arrangement. This output then feeds the pneumatic positioner, eliminating the need for a separately mounted transducer.

The instrument delivers an accurate valve stem position proportional to the DC current input signal. It is a field-proven design known for fast response and the ability to withstand vibrations found in most plant environments. Low steady-state air consumption contributes to efficient operation.

Zero and span adjustments are accessible with the cover removed, using a screwdriver and spanner. The unit can be switched between direct and reverse action through simple adjustments. Changes in supply pressure and valve load have minimal effect on positioner operation. The case, components, and gasket materials are selected to withstand harsh environments, and positioner bleed air purges internal parts for additional protection.

Technical Specifications

Application Industry

The 3582i is used with diaphragm-actuated, sliding-stem control valve assemblies in process industries. It handles flow, pressure, temperature, and level control applications. The adjustable zero and span range permits the use of all standard input signals, including split ranges. Because units from one positioner family cover a variety of control applications, basic spare parts inventory requirements are simplified.

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.