Foxboro B0123HE Control Module

The Foxboro B0123HE is not a PLC or electronic control module.
It is a pneumatic pressure regulator (instrument air regulator) used in Foxboro / Invensys process control systems.

Product Information

• Brand: Foxboro (Invensys / Schneider Electric)
• Model: B0123HE
• Type: Adjustable pneumatic pressure regulator (with filter function in many configurations)
• Function: Regulates instrument air pressure for control systems
• Connection: 1/4" NPT
• Input pressure: up to ~250 PSI (17 bar)
• Output pressure range: ~0.5 to 60 PSI (adjustable)

What it actually is

This device is used in process automation air systems, not electronics.

It:

• Converts high-pressure air → stable low-pressure air
• Supplies instrument air to valves and actuators
• Stabilizes pneumatic control systems

It does NOT:

• Perform logic control ❌
• Act as PLC/DCS module ❌
• Process signals electronically ❌

System Role (Simple)

Air compressor → filter system →
B0123HE regulator (this unit) →
control valves / actuators → process control

So it acts like a “precision air pressure stabilizer” in industrial automation.

Key Features

• Adjustable output pressure (0.5–60 PSI)
• Handles high input pressure (up to ~250 PSI)
• Stable instrument air regulation
• Used in pneumatic control loops
• Industrial corrosion-resistant design
• Often includes built-in filtering (variant dependent)

Typical Applications

• Foxboro DCS systems (instrument air supply)
• Oil & gas control systems
• Chemical plants
• Refinery pneumatic valve systems
• Process control instrumentation
• Air-powered actuator systems

Advantages

• Stable air pressure output for precise control valves
• Improves system reliability
• Reduces pressure fluctuation in pneumatic loops
• Industrial-grade durability
• Simple mechanical operation (no electronics)

Important Notes

• Not PLC ❌
• Not DCS controller ❌
• Not I/O module ❌
• Not electronic board ❌
• It is a pneumatic pressure regulator (instrument air device) ✔

Precautions

• Must be installed in clean instrument air system
• Do not exceed rated input pressure (~250 PSI)
• Keep air lines free of moisture/oil contamination
• Periodic maintenance of filter element may be required
• Incorrect adjustment can affect control valve performance