Foxboro FBM231 Single Power Supply Module

Technical Specifications:

• Input Voltage: 120 VAC or 240 VAC (auto-sensing), 50/60 Hz
• Input Current: 3A maximum at 120 VAC; 1.5A maximum at 240 VAC
• Output Voltage Rails:
  • +5V DC — 15A maximum
  • +24V DC — 8A maximum
  • ±15V DC — 1.5A maximum
• Redundancy Type: Non-redundant (single input, single output)
• Efficiency: Greater than 75% at full load
• MTBF: Greater than 150,000 hours
• Operating Temperature: 0°C to 60°C (32°F to 140°F)
• Protection: Overcurrent, overvoltage, short-circuit protection

Functional Features:

• Provides all required DC voltage rails from a single AC input source
• No redundancy — loss of AC input results in immediate system shutdown
• Built-in diagnostics monitor input voltage, output voltages, and load current
• Front panel LED indicators for POWER OK and FAULT status
• Simpler design and lower cost compared to FBM230 redundant version

Performance Parameters:

• Total Output Power: 180 Watts
• Ripple and Noise: Less than 100 mV peak-to-peak on all DC outputs
• Voltage Regulation: ±2% on all output rails
• Hold-Up Time: Greater than 15 ms at full load

Structural Characteristics:

• Form Factor: Standard Eurocard module (160 mm × 233 mm)
• Mounting: Horizontal rack mount in I/A Series chassis
• Connectors: Single backplane connector, screw-terminal AC input
• Cooling: Forced air via chassis fan
• Weight: Approximately 0.9 kg (1.98 lbs)

Working Principle:
AC mains power is rectified and filtered, then fed to multiple isolated DC-DC converter stages producing +5V, +24V, and ±15V rails. A single regulation loop monitors all outputs and adjusts duty cycles to maintain voltage within specification. No redundancy logic is present — the module operates as a single-point power source.

Advantages & Highlights:

• Lower cost than redundant FBM230 — ideal for non-critical applications
• Simplified wiring — single AC input connection
• Full diagnostic capability despite non-redundant design
• Universal AC input (120/240 VAC auto-sensing)

Applicable Industries:

• Small-scale process control
• Non-critical utility systems
• Educational and training systems
• Cost-optimized brownfield upgrades

Installation Requirements:

• Install in any available chassis slot
• Connect to a dedicated, protected AC circuit with appropriate breaker
• Ensure chassis cooling airflow is adequate (minimum 100 CFM)
• Verify chassis ground before energizing

Usage Precautions:

• This module provides NO redundancy — plan for system shutdown on power loss
• Do not use in safety-critical or SIS-related applications
• Verify load does not exceed 180 Watts total — consult chassis power budget
• Replace internal fuses only with 3A slow-blow type