Foxboro SRD991 Intelligent Digital Valve Controller Valve Positioner for Industrial Process

The SRD991 Intelligent Positioner from Schneider Electric (Foxboro) is a high-performance electropneumatic device designed to precisely control pneumatic valve actuators in industrial processes. It operates by receiving control signals from systems like the Foxboro I/A Series or other controllers, ensuring accurate valve positioning for linear or rotary actuators. Featuring advanced communication protocols such as HART, PROFIBUS-PA, or FOUNDATION Fieldbus, it includes a multilingual graphical LCD display for easy monitoring and configuration. Intrinsically safe (Ex ia) versions are available for hazardous environments, making it suitable for demanding applications where reliability and safety are paramount.

• Intelligent Control: Autostart functionality for quick setup, with diagnostics to analyze stroke data and prevent issues like oscillation or hunting.
• Mounting Versatility: Supports NAMUR left/right hand mounting for linear actuators, direct mounting, and rotary actuator compatibility with feedback levers to minimize backlash.
• Communication Options: HART for 4-20 mA signals, PROFIBUS-PA, FOUNDATION Fieldbus, or basic versions without communication.
• Electrical Options: Binary inputs/outputs, position feedback (4-20 mA with alarm), inductive limit switches (NAMUR or DIN 19234 compliant).
• Pneumatic Design: Single or double-acting configurations; supply pressure 1.4-6 bar, with warnings to avoid injury from bursting parts.
• Safety and Durability: Intrinsically safe Ex ia, temperature range -40°C to +80°C, IP66 protection.
• User Interface: Graphical LCD for full-text display, multilingual support for global use.

Ideal for process industries such as oil & gas, chemical, and water treatment, where precise valve control is essential. Used with pneumatic actuators for throttling valves, on/off applications, or integrated with control systems for automated flow regulation. The top-mounted version suits small actuators without yokes, while diagnostics support predictive maintenance in harsh environments.

1. How do I mount the SRD991 to a linear actuator? Use NAMUR left or right-hand mounting, ensuring the feedback lever's flat side points to arrow 26 with ±45° working angle; carrier bolt in slot touching compensating spring.
2. What is the maximum supply pressure? 6 bar, but do not exceed actuator limits to avoid bursting parts or injury.
3. Does it support double-acting actuators? Yes, connect y1 and y2 pneumatic outputs; for single-acting, y1 only.
4. How to handle electrical connections in hazardous areas? Follow EX EVE0001 safety requirements; use intrinsically safe circuits per certificate.
5. What if there's mechanical backlash? Use original mounting parts to prevent poor control or long Autostart duration.

Phone/WeChat/WhatsApp: +8613916209596

Email: svetama@gbsxj.com

• SRD960: Explosion-proof intelligent positioner.
• SRI986: Basic electropneumatic positioner.
• Type 766 Actuator: Compatible pneumatic actuator for research control valves.
• Foxboro I/A Series: Control systems for integration.
• SRD991 RCV: Top-mounted variant for small actuators.