ASCO Solenoid Valves Foxboro SRD991 Smart Digital Valve Controller Valve Positioner for Industrial Process

Schneider Electric's SRD991 is an advanced intelligent positioner that enhances pneumatic valve actuator performance through precise signal processing and feedback. It integrates seamlessly with control systems via HART, PROFIBUS-PA, or FOUNDATION Fieldbus protocols, offering diagnostics for stroke analysis and fault prevention. Designed for both linear and rotary actuators, it features intrinsically safe options for explosive atmospheres and a robust build for industrial reliability.

• Diagnostics and Configuration: Built-in tools for data analysis, configurable via DTM or LCD interface.
• Pneumatic Connections: G1/4 or NPT threads; single/double acting with closed unused ports.
• Electrical Terminals: Setpoint input (4-20 mA), option boards for binary I/O, 4-20 mA feedback, inductive switches.
• Mounting Options: Direct or NAMUR for linear (up to 260 mm travel), rotary with clearance for thermal expansion.
• Safety Features: Grounding screws, warnings for pressure limits and finger safety during air connection.
• Communication Flexibility: Supports PC-based configuration; multilingual full-text LCD.
• Explosion Protection: Ex ia certified, suitable for hazardous areas.

Engineered for valve control in petrochemical, pharmaceutical, and power generation sectors. Excels in applications requiring high precision, such as flow control in pipelines or pressure regulation in tanks. The RCV variant is tailored for research control valves with integrated actuators.

• How to connect for HART communication? Use terminals 11/12 for 4-20 mA input; ensure min. 250 Ω loop resistance.
• What causes long Autostart duration? Mechanical backlash; verify original feedback lever and tight mounting.
• Can it be used without communication? Yes, basic version (SRD991-xD) for standard 4-20 mA control.
• How to adjust for rotary actuators? Ensure 1 mm clearance with washers on spindle; do not tighten grub screw against thread.
• What air quality is required? ISO 8573-1 Class 3: free of oil, dust, water; particle class 2, oil class 3.

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• 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.