Key Parameters & Specifications Parameter / Feature Category Description Product Name Fisher™ 3720 Series Pneumatic Valve Positioner Type Force-Balance, Pneumatic (I/P), Cam and Lever Primary Application Positioning of rotary valves (ball, butterfly, plug) with piston actuators. Input Signal Standard: 3-15 psig (0.2-1.0 bar). Other input ranges are available. Supply Pressure Up to 150 psig (10.3 bar). Must be sufficient to meet the actuator's pressure requirements. Output to Actuator Supply pressure dependent. Provides controlled air pressure to one or both sides of the piston actuator. Action Field-reversible between direct and reverse action. Feedback Mechanism Cam and Lever. The cam profile is designed to linearize the relationship between the input signal and the valve's rotational travel. Flow Capacity (Relay) High-capacity relay for fast filling and exhausting of piston actuators, ensuring quick valve response. Mounting Direct-mounted to the actuator. Connects to the valve shaft via a feedback lever and link. Enclosure Weatherproof and corrosion-resistant aluminum enclosure. Actuator Compatibility Piston Actuators: • Double-acting • Single-acting (spring-return) Approvals Suitable for use in hazardous areas due to its purely pneumatic design. Can have specific certifications like FM, CSA, ATEX, etc.