Foxboro FBM24A / FBM25A Product Description

The Foxboro FBM24A and FBM25A are high‑density, channel‑isolated discrete output interface modules within the Foxboro I/A Series™ and EcoStruxure Foxboro DCS (Schneider Electric) Compact 200 Series. Designed as robust, externally powered digital output cards, they provide reliable on/off control for a wide range of field devices in process industries. Optimized for full channel‑to‑channel galvanic isolation, multi‑voltage external excitation, and harsh‑environment operation, these modules deliver dependable switching for solenoids, motor starters, contactors, lamps, and alarm beacons. Both models support hot‑swap, redundant communication, and comprehensive diagnostics, making them ideal for high‑availability control in chemical, oil and gas, power, and water treatment applications.

The FBM24A and FBM25A each provide 16 fully galvanically isolated discrete output channels, every channel electrically separated from adjacent channels and ground, with a withstand rating of 600 V AC for one minute. This eliminates ground loops, minimizes electrical noise, and prevents cross‑channel interference—critical for systems relying on external power sources. All channels support external‑only sourcing, meaning the module does not supply field power and works with customer‑provided 15–60 VDC, 120 VAC/125 VDC, or 240 VAC supplies.

Each output channel is rated for 2 A continuous current (2.25 A maximum) at 60 VDC, with an inrush capacity of 8 A for 20 ms at 30°C, suitable for inductive loads like relays and solenoids. The on‑state voltage drop is ≤ 0.2 V at full load, and off‑state leakage current is ≤ 0.1 mA, ensuring clean switching and minimal power loss. Outputs are solid‑state, normally open switches with configurable fail‑safe modes: users can preset outputs to hold the last state or de‑energize on communication loss or fault.

A key difference between the two models lies in their expansion and compatibility capabilities: the FBM24A serves as a main discrete output module with standard I/O mapping, while the FBM25A functions as an enhanced expansion output module, supporting extended addressing and additional diagnostic features for larger system configurations. Both modules execute discrete I/O or ladder logic programs, with configurable input filtering time, fail‑safe rollback, and continuous or transient output modes.

Designed for high availability, both modules support hot‑swap installation and replacement, enabling online maintenance without process shutdown. Communication with Foxboro FCP/ZCP controllers uses a redundant 2 Mbps HDLC fieldbus, providing error‑checked data transfer with automatic path failover. Onboard LED indicators display power, communication status, and individual channel state (active/fault), allowing quick on‑site troubleshooting. Advanced diagnostics monitor channel health, communication integrity, and power supply status, reporting faults to the DCS in real time.

Constructed with a rugged, conformal‑coated PCB and durable housing, the FBM24A/FBM25A are certified for ISA S71.04 Class G3 harsh environments (dust, moisture, vibration). They operate reliably in extended temperature ranges and support 24 VDC redundant power input with automatic failover for maximum uptime.

Manufacturer: Foxboro (Schneider Electric)Compatible Systems: Foxboro I/A Series DCS (v7.0+), EcoStruxure Foxboro (Foxboro Evo™) DCSModel/Part Number: FBM24A (standard discrete output); FBM25A (enhanced expansion discrete output)Module Type: 16‑channel externally sourced discrete output module (16DO)Output Channels: 16 fully galvanically isolated channels; channel‑to‑channel and channel‑to‑ground isolationExternal Voltage Ranges: 15–60 VDC, 120 VAC / 125 VDC, 240 VACContinuous Current Rating: 2 A per channel (2.25 A maximum) at 60 VDC; 0.5 A per channel at 240 VACInrush Current: 8 A for 20 ms at 30°COn‑State Voltage Drop: ≤0.2 V at 2.25 AOff‑State Leakage Current: ≤0.1 mAIsolation Withstand: 600 V AC for 1 minute (channel‑to‑channel/ground)Communication: Redundant 2 Mbps HDLC fieldbus (to FCP/ZCP controllers)Power Supply: 24 VDC (+5%/–10% tolerance), redundant input supported; no internal field powerPower Consumption: Max 10 W; typical 8 WOperating Temperature: –20 °C to +70 °CStorage Temperature: –40 °C to +85 °CRelative Humidity: 5%–95% non‑condensingVibration: 0.05 g rms, 5–500 HzShock: 5 g, 20 ms half‑sineAltitude: –300 m to +3,000 mEnclosure: Rugged housing, conformal‑coated PCB; IP20 ratingDimensions (W × H × D): Approximately 45 mm × 114 mm × 104 mmWeight: Approximately 0.3 kgCertifications: CE, UL, CSA, ATEX Zone 2, IECEx, ISA S71.04 Class G3; EMC Class A (IEC 61000‑6‑2)Reliability: MTBF > 100,000 hours; hot‑swap capable; redundant communication and power support; full channel isolation for noise immunity.

The FBM24A/FBM25A are ideal for high‑density discrete control requiring external excitation and full channel isolation in space‑limited panels, with the FBM25A suited for larger or more complex system expansions. In chemical and petrochemical plants, they drive solenoid valves, valve actuators, and burner ignition relays powered by 120/240 VAC external sources, supporting batch and continuous process control with minimal electrical interference.

In oil and gas facilities—including refineries, offshore platforms, and gas processing plants—they control safety shutdown valves, wellhead actuators, and flare ignition systems operating at 240 VAC, ensuring reliable operation in hazardous areas with high noise immunity.

In power generation, the modules manage breaker trip coils, turbine latching relays, and boiler purge valves using 125 VDC external power, supporting safe startup, shutdown, and emergency trip functions with fast fault detection.

In water and wastewater treatment, they control dosing pumps, aeration blowers, and motorized valves with 15–60 VDC external excitation, enabling precise process control and regulatory compliance.

In pharmaceutical, food and beverage, and general manufacturing, their compact size, full channel isolation, and multi‑voltage compatibility make them perfect for panel‑side I/O consolidation, machine interlocking, and alarm beacon control in both hygienic and harsh environments.

The FBM24A/FBM25A mount on standard DIN rails or horizontally on a Compact 200 Series backplane inside Foxboro I/A Series or EcoStruxure Foxboro cabinets, connecting to a dedicated baseplate for backplane power and redundant HDLC fieldbus communication. Field wiring terminates at a mating termination assembly (TA) equipped with screw terminals, per‑channel fuses, and knife disconnect/test sockets for maintenance. TAs support local/remote wiring and accommodate 15–60 VDC, 120 VAC/125 VDC, or 240 VAC external power, with options for relay outputs, solid‑state switching, and power distribution fusing.

Configuration is performed via Foxboro DCS software: set output fail‑safe states (hold or off), map channels to DCS tags, enable redundant communication/power, and configure fault reporting parameters. The modules are plug‑and‑play compatible with existing Foxboro systems and support hot‑swap replacement to minimize downtime.

For high availability, two FBM24A or FBM25A modules can be configured as a redundant pair with automatic fault detection and switchover, ensuring seamless control continuation if one module fails. The FBM25A additionally supports expanded I/O addressing for integration with up to 128 200 Series FBMs in a single system, making it suitable for large‑scale plant expansions.

Routine maintenance includes visual inspection for physical damage, loose connections, or dust buildup, and verification of front‑panel LEDs for normal power, communication, and channel status. Periodic testing of output switching performance, load capacity, and redundant failover is recommended, especially in high‑vibration or corrosive environments.

The conformal coating 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.

The FBM24A/FBM25A come with a 12‑month standard warranty against manufacturing defects, with extended warranty options available for long‑term operational reliability.