Foxboro FBM231 Product Description

The Foxboro FBM231 (part number P0926GV) is a redundant four-port serial communication interface module (Field Device System Integrator, FDSI) for the Foxboro I/A Series and EcoStruxure Foxboro (Foxboro Evo™) DCS platforms, manufactured by Schneider Electric. It is an enhanced, redundancy-enabled variant of the FBM230, designed to serve as a high-reliability bridge between multi-type serial field devices and the DCS. The FBM231 supports dual-module redundant operation, making it ideal for mission-critical process control applications where zero downtime is required. It connects PLCs, drives, meters, and third-party smart instruments, enabling reliable bidirectional data transmission and protocol conversion in harsh industrial environments.

The FBM231 provides four independent, software-configurable serial ports, each individually set to RS-232, RS-422, or RS-485 physical layers, offering maximum flexibility to interface with diverse serial devices. It complies with EIA RS-232/422/485 standards, supporting point-to-point (RS-232) and multi-drop (RS-485/422) topologies.

A defining feature is its native redundant support: two FBM231 modules operate as a master-tracker pair, with automatic role switching if the master fails (via heartbeat monitoring) or manual switching via system tools. This ensures seamless, fault-tolerant communication without process interruption.

It supports downloadable protocol drivers from the Foxboro protocol library, compatible with common industrial protocols such as Modbus RTU/ASCII, DF1, and custom serial protocols, enabling seamless integration of third-party equipment. The module handles 8-bit characters with selectable odd, even, or no parity, plus 1 or 2 stop bits; baud rates range from 300 bps to 115,200 bps, accommodating various speed requirements.

Device capacity includes up to 64 RS-485 multi-drop devices per module or 4 direct-connected RS-232/RS-422 devices, with support for up to 2000 Distributed Control Interface (DCI) block connections for large-scale data mapping. It supports multiple data types: 2/4-byte signed/unsigned integers, 4-byte IEEE single-precision floats, and binary values, with automatic conversion via drivers.

Communication with the DCS controller (FCP/ZCP) uses a redundant 2 Mbps HDLC fieldbus with automatic A/B path failover, ensuring uninterrupted data exchange. The FBM231 features hot-swap capability, allowing online replacement without DCS shutdown or process interruption, critical for high-availability operations.

Each channel provides 600 VAC galvanic isolation between ports and between ports and chassis, protecting against electrical noise and transient spikes. Rugged industrial design includes a compact enclosure with conformal-coated PCB, rated for ISA S71.04 Class G3 harsh environments, withstanding dust, moisture, and vibration. Front-panel LED indicators clearly display power, communication, and port status for quick on-site troubleshooting. Built-in advanced diagnostics continuously monitor communication health, signal quality, and power status, delivering real-time fault alerts to minimize downtime.

Manufacturer: Foxboro (Schneider Electric)Compatible Systems: Foxboro I/A Series DCS, EcoStruxure Foxboro (Foxboro Evo™) DCSModel/Part Number: FBM231 (P0926GV)Communication Ports: 4 independent, isolated serial portsPort Configuration: Each port software-configurable as RS-232, RS-422, or RS-485Supported Protocols: Modbus RTU/ASCII, DF1, custom serial protocols (downloadable drivers)Baud Rate: 300 bps to 115,200 bpsParity/Stop Bits: Odd, even, or no parity; 1 or 2 stop bitsDevice Capacity: Up to 64 RS-485 devices or 4 RS-232/RS-422 devices per moduleData Capacity: Up to 2000 DCI block connectionsData Types: 2/4-byte integers, 4-byte IEEE floats, binary valuesRedundancy: Dual-module master-tracker redundancy, automatic failover via heartbeatCommunication with DCS: Redundant 2 Mbps HDLC fieldbus, A/B path redundancy with automatic failoverPower Supply: 24 V DC (+5%/–10% tolerance); max power consumption ≤7 WIsolation: 600 VAC (channel-to-channel, channel-to-chassis, 1-minute withstand)Operating Temperature: –20 °C to +70 °C (standard); –40 °C to +70 °C (extended)Storage Temperature: –40 °C to +85 °CRelative Humidity: 5%–95% non-condensingAltitude: –300 m to +3,000 m (–1,000 ft to +10,000 ft)Enclosure: Compact industrial enclosure, conformal-coated PCB; IP20 ratingDimensions (W × H × D): Approximately 49 mm × 99 mm × 72 mm (1.9 in × 3.9 in × 2.8 in)Weight: Approximately 0.28 kg (0.62 lb)Certifications: CE, UL, CSA, ATEX Zone 2, IECEx, ISA S71.04 Class G3; compliant with EMC Class A (IEC 61000-6-2)

The FBM231 is designed for high-availability process industries requiring redundant serial device integration for critical monitoring and control. In chemical and petrochemical plants, it connects DCS systems to Modbus RTU-compatible flow meters, pressure transmitters, and valve positioners on reactors and pipelines, with redundancy ensuring no data loss during module faults.

In oil and gas facilities—including refineries, offshore platforms, and gas processing stations—it interfaces with serial-based wellhead sensors, tank level gauges, and compressor controllers, monitoring production parameters and controlling equipment in hazardous explosive atmospheres with fault tolerance.

In power generation plants, the FBM231 links DCS systems to PLCs, vibration monitors, and excitation controllers for boilers, turbines, and generators, where continuous operation is critical to avoid costly outages.

In water and wastewater treatment plants, it connects to serial pH meters, dissolved oxygen sensors, and dosing pump controllers, supporting precise and compliant treatment process control with redundant communication for regulatory-critical data.

In pharmaceutical, food and beverage, and fine chemical industries, the FBM231’s high isolation, regulatory certifications, and redundant design make it suitable for controlled, hygienic, and hazardous processes requiring strict signal integrity and zero downtime.

The FBM231 installs on standard DIN rails in Foxboro I/A Series or EcoStruxure Foxboro DCS cabinets, mounting on a dedicated I/A Series baseplate for power distribution and redundant fieldbus communication with the DCS backplane. For redundant operation, two FBM231 modules are installed side-by-side, with field wiring routed to two separate termination assemblies (TAs) for dual-path connectivity.

Field wiring connects to a compatible termination assembly (TA), which provides surge protection, signal conditioning, and switch-selectable termination resistors for RS-422/RS-485 interfaces. For RS-232 communication, the TA features DB-25 connectors with switch-selectable pinouts to match slave devices. Standard shielded twisted-pair cables are recommended for RS-422/RS-485 wiring, with proper grounding and termination to optimize noise immunity.

System configuration is performed via Foxboro DCS software, enabling users to configure port parameters (baud rate, parity, stop bits), assign slave devices, map process data to DCS tags, download protocol drivers, and set up redundant master-tracker operation. The module is plug-and-play compatible with existing Foxboro systems, requiring minimal on-site setup and supporting hot-swap replacement. It integrates seamlessly with other I/A Series modules, forming a unified, scalable process control solution.

Routine maintenance for the FBM231 includes visual inspection of the enclosure for physical damage, dust accumulation, or loose connections, and verification of front-panel LED indicators for normal power, communication, and port operation. Periodic testing of serial communication integrity, signal quality, power supply stability, and redundant failover functionality is recommended, especially in high-vibration, corrosive, or strong electromagnetic interference environments. The conformal coating on the PCB protects against moisture and dust, reducing cleaning frequency.

Faulty modules can be repaired by authorized Schneider Electric service providers, with standard and expedited repair options available for critical applications. The FBM231 comes with a 12-month standard warranty against manufacturing defects, with extended warranty options available for long-term operational reliability. For redundant configurations, regular failover testing ensures the system can seamlessly switch to the tracker module if the master fails, maintaining uninterrupted process control。