Foxboro FBM218 Product Description

The Foxboro FBM218 is a high‑performance 8‑channel HART analog output module in the Compact 200 Series I/O family, manufactured by Foxboro (Schneider Electric) for Foxboro I/A Series and Foxboro Evo™ distributed control systems. It serves as the key interface between the DCS and HART‑enabled smart valve positioners, actuators, and control valves, providing both 4–20 mA analog control signals and superimposed HART FSK digital communication. Designed for high accuracy, galvanic isolation, and redundant operation, the FBM218 supports bidirectional communication with HART field devices, enabling remote configuration, calibration, and diagnostics. Its compact, rugged construction and hot‑swap capability make it ideal for high‑availability, harsh‑environment process control applications across industries.

The FBM218 provides eight fully isolated output channels, each independently configurable for either standard 4–20 mA analog output or HART‑enhanced 4–20 mA output with superimposed digital FSK signals. Channels are galvanically isolated from each other, ground, and module logic via optical and transformer isolation, withstanding up to 600 V AC for one minute between channels and earth, eliminating ground loops and electrical crosstalk.

Each channel integrates a dedicated HART FSK modem for bidirectional digital communication at 1200 baud, supporting HART protocol versions 5, 6, and 7. The DCS can retrieve device status, diagnostics, and process data, and perform remote parameterization and calibration via HART universal, common practice, and device‑specific commands. The module provides sufficient loop resistance for direct connection of HART hand‑held terminals or PC‑based configurators without additional hardware.

High‑precision analog output circuitry delivers ±0.1% full‑scale accuracy with excellent stability across temperature variations. Output current is user‑selectable per channel (4–20 mA), with short‑circuit and overcurrent protection to safeguard both the module and field devices. Redundant FBM‑level operation is supported via module pairing, ensuring continuous control even if one module fails.

Communication with the DCS controller (FCP/ZCP) or fieldbus communication module (FCM) uses a redundant 2 Mbps HDLC fieldbus with automatic A/B path failover, preventing data loss during communication path faults. The module supports hot‑swap, allowing online replacement without shutting down the DCS or interrupting process control.

Rugged construction includes an extruded aluminum enclosure and conformal‑coated PCB, rated for ISA S71.04 Class G3 harsh environments to resist dust, moisture, vibration (7.5 m/s², 5–500 Hz), and wide temperature fluctuations. Front‑panel LEDs indicate power, channel activity, and fault status for quick on‑site troubleshooting.

Manufacturer: Foxboro (Schneider Electric)Compatible Systems: Foxboro I/A Series, Foxboro Evo™ DCSNumber of Channels: 8 galvanically isolated output channelsOutput Signal Types: User‑selectable per channel: 4–20 mA analog; 4–20 mA with HART FSK superimposedHART Protocol Support: Versions 5, 6, 7; half‑duplex, 1200 baud; parity check and 32‑bit CRC error verificationAnalog Output Accuracy: ±0.1% full scaleIsolation: 600 V AC for 1 minute (channel‑to‑earth); channel‑to‑channel and channel‑to‑logic isolationPower Supply: 24 V DC (18–32 V DC operating range); max power consumption 3 WOperating Temperature: –20 °C to +70 °C (–4 °F to +158 °F)Storage Temperature: –40 °C to +70 °C (–40 °F to +158 °F)Relative Humidity: 5%–95% non‑condensingAltitude: –300 m to +3,000 m (–1,000 ft to +10,000 ft)Enclosure: Extruded aluminum, conformal‑coated PCB; IP20 ratingDimensions: Approximately 102 mm × 45 mm × 104 mm (4.0 in × 1.8 in × 4.1 in)Weight: 0.3 kg (0.66 lb)Certifications: CE, UL, CSA, ABS Type Approval, Bureau Veritas Marine; compliant with ISA S71.04 Class G3

The FBM218 is widely used in process industries requiring precise, reliable control of HART‑enabled final control elements. In chemical and petrochemical plants, it controls HART smart valve positioners, actuators, and control valves on reactors, distillation columns, and pipelines, enabling remote valve monitoring and calibration to optimize process efficiency and safety.

In oil and gas facilities, including refineries, offshore platforms, and gas processing stations, it modulates control valves for flow, pressure, and level regulation, supporting emergency shutdown (ESD) systems and ensuring safe, efficient hydrocarbon production and transportation.

In power generation plants, it controls boiler feedwater valves, steam turbine control valves, and auxiliary system actuators, providing accurate analog control and HART diagnostics for critical power plant components. In water and wastewater treatment plants, it regulates control valves for flow, pH, and level control, supporting HART‑based valve status monitoring and maintenance.

In pharmaceutical, food and beverage, and fine chemical industries, the FBM218’s high accuracy and HART communication capabilities ensure precise process control and compliance with regulatory requirements, while its redundant and hot‑swap features minimize unplanned downtime.

The FBM218 installs on standard DIN rails in Foxboro I/A Series or Evo™ DCS cabinets, mounting on a dedicated Compact 200 Series baseplate for power and redundant fieldbus communication with the DCS backplane. Field wiring connects to compatible termination assemblies (TAs), which provide channel isolation, surge protection, and field device connection points, supporting both local and remote wiring configurations.

Standard shielded industrial cables are recommended for field wiring, with proper grounding to optimize noise immunity and ensure reliable HART communication. Each channel is wired to a HART‑enabled actuator or control valve, with loop power supplied via the TA or external power sources as required.

System configuration is performed via Foxboro DCS software, enabling users to set output ranges, configure HART communication parameters, and assign redundant operation modes. The module is plug‑and‑play compatible with existing Foxboro systems, requiring minimal on‑site setup. Hot‑swap capability allows online replacement without system shutdown, while redundant fieldbus communication ensures continuous control during path faults. It integrates seamlessly with other Compact 200 Series modules, forming a unified, scalable process control solution.

Routine maintenance includes visual inspection of the aluminum enclosure for physical damage, dust accumulation, or loose connections, and verification of front‑panel LED indicators for normal operation. Periodic testing of output accuracy, loop resistance, and HART communication integrity 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. The FBM218 comes with a 12‑month standard warranty against manufacturing defects, with extended warranty options available for long‑term operational reliability. For redundant configurations, periodic testing of module failover functionality is recommended to ensure fault tolerance readiness.