KOSO EP800 Electro-Pneumatic Valve Positioner with 4-20mA Signal Aluminum Alloy Housing and Split-Range Control

Product Overview

The KOSO EP800 is an electro-pneumatic valve positioner designed for positioning pneumatic actuator-operated control valves. It receives a DC 4-20mA signal from a controller and converts it into output air pressure to control the actuator. Simultaneously, it detects and feeds back the actuator displacement to provide accurate positioning in response to the input signal.

The EP800 series can be used with both single-acting and double-acting actuators. It is available in three main types: EPA800 for single acting, EPC800 for double acting, and EPB800 for the 5200LA actuator. The unit features a non-bleeding pilot valve design and can be easily converted between single-acting and double-acting configurations, as well as between direct and reverse action.

The positioner supports split-range control through span and zero adjustment, with adjustable ranges of 4-12 mA and 12-20 mA DC. The housing is made of aluminum alloy with a weatherproof, explosion-proof, or intrinsically safe explosion-proof enclosure option. Common specifications are available from stock for fast delivery.

Technical Specifications

Application Industry

The KOSO EP800 is used in power generation, petrochemical, chemical processing, and general industrial automation. It is suitable for positioning pneumatic actuator-operated control valves in process control loops. The series supports both straight-stroke and angular-stroke actuators.

Common Problems

• Positioner does not respond to input signal: Check supply pressure is within 140~700 kPa. Verify pneumatic connections are secure. Check the pilot valve for blockage.

• Valve position does not match input signal: Check zero and span calibration. Verify that the action direction (direct or reverse) is correctly set. Check that the feedback linkage is properly connected.

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

• Split range not working: Verify span and zero adjustment for the desired split range (4-12 mA or 12-20 mA DC).

• Air leakage from positioner: Check the pilot valve and diaphragm for wear. Inspect the O-rings and seals.

Replacement Models

The KOSO EP800 is a mature electro-pneumatic positioner platform. The KGP5000 series is the smart valve positioner alternative from the same product line, offering digital communication and advanced diagnostics. For cross-vendor alternatives, verify actuator mounting, travel range, and input signal compatibility before ordering.