Foxboro SRI986-BIDS7ZZZNA Valve Positioner

Foxboro SRI986-BIDS7ZZZNA Valve Positioner (Electro-Pneumatic Positioner)

 

 

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The Foxboro SRI986-BIDS7ZZZNA is an electro-pneumatic valve positioner (also called an I/P positioner) used to precisely control the opening position of a pneumatic control valve actuator in industrial process systems.

It belongs to the Foxboro (Schneider Electric) SRI986 series, widely used in DCS / process control applications like oil & gas, chemical plants, power plants, and water treatment systems.

Key Specifications

• Model: SRI986-BIDS7ZZZNA
• Brand: Foxboro (Schneider Electric / Foxboro Eckardt)
• Product Type: Electro-Pneumatic Valve Positioner
• Input Signal:
  • 4–20 mA control signal
• Output:
  • Pneumatic air pressure to actuator
• Supply Air:
  • Clean instrument air (typically ~1.4–6 bar / up to ~90 psi)
• Mounting:
  • NAMUR standard / IEC 534 actuator mounting
• Function:
  • Converts electrical signal → mechanical valve position
• Optional Features (variant dependent):
  • HART communication
  • Position feedback transmitter
  • Limit switches
  • Explosion-proof / intrinsic safety options

How it works (simple explanation)

This device is basically the translator between PLC/DCS and the valve:

DCS / PLC signal (4–20 mA)
↓
SRI986 Positioner
↓
Air pressure control
↓
Pneumatic actuator moves valve stem
↓
Valve opens/closes precisely

It continuously corrects position using feedback, so the valve matches the command signal accurately.

Main Functions

• Converts 4–20 mA signal into valve position
• Automatic closed-loop control of valve stroke
• Compensates for:
  • Friction
  • Hysteresis
  • Air pressure variation
• Improves valve response speed and accuracy
• Enables precise flow / pressure / temperature control

Features & Advantages

• High positioning accuracy (closed-loop control)
• Stable response even under changing load conditions
• Adjustable gain, damping, and stroke calibration
• Suitable for rotary and linear actuators
• Optional HART diagnostics for remote monitoring
• Explosion-proof versions for hazardous areas
• Robust industrial design for harsh environments