Samson 4763 Compact Electropneumatic Valve Positioner 4-20mA for Pneumatic Actuators

Product Overview

The Samson 4763 is a compact electropneumatic positioner intended for mounting on pneumatic control valves. It is a single-acting instrument that compares the control system's input signal with the actual valve stem position and then sends a corresponding pneumatic pressure to the actuator. The housing is die-cast aluminum, and the unit can be mounted in any orientation without being affected by mechanical vibration. The operating direction can be reversed in the field. Adjustable proportional band and air output capacity allow fine-tuning for specific applications. The 4763 accepts a 4-20mA or 1-5mA electrical input. It uses a force-balance flapper-nozzle system. Optional pressure gauges allow monitoring of supply air and signal pressure.

Technical Specifications

Application Industry

The Samson 4763 is used in chemical and petrochemical processing, power generation, pulp and paper, and general industrial automation. It is suitable for throttling service and applications requiring precise valve positioning. The compact design and vibration resistance make it suitable for demanding process environments.

Common Problems

• Positioner does not respond to input signal: Check supply pressure is within 1.4~6 bar. Verify pneumatic connections are secure. Check that the nozzle assembly is not clogged.

• Valve position does not match input signal: Check the proportional band (P-band) setting. Verify that the operating direction (direct or reverse) is correctly set. Recalibrate the zero point.

• Erratic operation or oscillation: Inspect for air leaks in tubing and fittings. Check for excessive friction in valve packing or actuator. Verify that the air output capacity setting is appropriate.

• Zero point calibration error: The zero point is out of range. Check mounting and re-adjust the zero point.

• Low supply pressure: Verify that supply pressure meets the minimum requirement of 1.4 bar. Check the air supply regulator.

Replacement Models

The Samson 4763 will be discontinued in the near future. The direct replacement is the TROVIS 3730-1, which is the next-generation smart positioner with HART communication and enhanced features. The Type 3767 is also available as an alternative. The 4763 is a predecessor to the 3730 series and shares similar mounting compatibility. For cross-vendor alternatives, verify actuator mounting, travel range, and communication protocol before ordering.