Schneider Electric / Invensys / Foxboro FBM04 0-20mA I/O Interface Module

The Schneider Electric/Invensys/Foxboro FBM04 is a 0-20mA I/O Interface Module engineered for distributed control and industrial automation systems. It delivers four isolated analog input channels and four isolated analog output channels, enabling bidirectional signal conversion between field instruments and a redundant Fieldbus network. The module bridges transmitters, actuators, and control logic with high-precision current-loop signal conditioning.

Technical Specifications

• Input voltage range (redundant): 26 to 42 V DC


• Maximum power consumption: 14 W


• Maximum heat dissipation: 12 W


• Electrical isolation: 600 V AC for 1 minute between any channel and earth, or between channels Analog Input Channels (4×)


• Input range: 0 to 20.4 mA DC per channel


• Accuracy: ±0.05% of span at 25°C


• Temperature coefficient: 100 ppm/°C


• Channel impedance: 61.5 Ω nominal


• Common-mode rejection: >100 dB at 50 or 60 Hz


• Normal-mode rejection: >95 dB at 50 or 60 Hz


• Conversion time: Software configurable


• Monotonicity guaranteed for increasing input signals Analog Output Channels (4×)


• Output range: 0 to 20.4 mA DC per channel


• Maximum load: 735 Ω


• Compliance voltage: 18.6 V nominal at 20 mA DC


• Accuracy: ±0.05% of span at 25°C


• Temperature coefficient: 100 ppm/°C


• Linearity error: ±0.025% of span (monotonic)


• Resolution: 12 bits


• Settling time: 100 ms to 1% band for 10 to 90% step change


• Output processing delay: 30 ms maximum

Key Features

• Four fully isolated input and output channel pairs eliminate cross-talk and ground-loop issues


• Accepts 4-20mA transmitters and self-powered 20mA sources on inputs


• High input impedance (61.5 Ω) minimizes loading effects on transmitter circuits


• Monotonic output ensures signal integrity in closed-loop control applications


• Configurable conversion timing optimizes response for process requirements

Typical Applications

• Analog sensor integration in I/A Series distributed control architectures


• Process valve and actuator control loops


• Transmitter signal conditioning and isolation


• Fieldbus gateway bridging for legacy 4-20mA field instruments

Compatibility & Integration The FBM04 integrates with Foxboro I/A Series platforms via redundant Fieldbus communication. The module accepts standard industrial current-loop signal levels and operates across a 26–42 V DC redundant supply. Part number P0400YE identifies this unit in legacy documentation.