The Foxboro SRD991 (Schneider Electric) is a microprocessor-based intelligent valve positioner designed to accurately control pneumatic valve actuators. It supports single-acting and double-acting actuators for both linear and rotary applications. The device offers local configuration via push-buttons and a multilingual graphical LCD, advanced self-diagnostics, and multiple communication options (4–20 mA, HART, PROFIBUS-PA, FOUNDATION Fieldbus H1). It is engineered for easy mounting, fast Autostart commissioning, and predictive maintenance in process industries.
| Parameter | Specification |
|---|---|
| Stroke range | 8–260 mm (0.3–10.2 in) with standard lever |
| Rotation angle | Up to 95° (optional up to 300°) |
| Air supply | 1.4–6 bar (20–90 psig); up to 7 bar with spool valve |
| Air quality | ISO 8573-1 Class 2 solids, Class 3 oil |
| Pneumatic action | Single or double acting |
| Protection | IP66 / NEMA 4X |
| Ambient temperature | –40 °C to +80 °C (–40 °F to +176 °F) |
| Weight | ≈1.7 kg (single), ≈2 kg (double) |
| Electrical connections | M20*1.5 or ½-14 NPT |
| Pneumatic connections | G¼ or ¼-18 NPT |
| Linearity / Hysteresis | <0.4 % / <0.3 % of travel span |
| Certifications | ATEX, IECEx, FM, CSA, SIL 3 capable, others |
Process control valves in oil & gas, chemical, petrochemical, power generation, pharmaceutical, and water treatment plants. Ideal for continuous control, ESD (emergency shutdown) valves via PST, and predictive maintenance strategies.
A: After mechanical mounting and pneumatic/electrical connections, select mounting type and run Autostart via the local keys and LCD (typically two main steps).
A: 4–20 mA (no protocol), HART, PROFIBUS-PA, and FOUNDATION Fieldbus H1.
A: Yes, with appropriate NAMUR or direct-mount kits; flat side of spindle must point toward the housing arrow.
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