Foxboro FBM39 Fieldbus Interface Module

The Foxboro FBM39 is a high‑performance, fault‑tolerant fieldbus communication module within the Foxboro I/A Series™ and EcoStruxure Foxboro (Foxboro Evo™) DCS portfolios, originally engineered by Invensys and now part of Schneider Electric’s industrial automation solutions. Designed as a critical link between the DCS and intelligent field devices, it delivers zero‑data‑loss transmission, redundant communication paths, and rapid diagnostics for real‑time process control. Optimized for high noise immunity, hazardous area compatibility, and seamless integration with HART and Foundation Fieldbus devices, the FBM39 supports hot‑swap maintenance, embedded safety logic, and a rugged compact form factor—making it ideal for oil and gas, chemical, power generation, and pipeline automation applications requiring ultra‑reliable fieldbus connectivity.

The FBM39 integrates dual independent transceivers to establish redundant fieldbus communication paths, ensuring uninterrupted data exchange even if one transceiver or cable fails. Built on a zero‑data‑loss framework, it guarantees the integrity of real‑time sensor and actuator data across large‑scale process environments, eliminating critical information gaps during transmission. This redundancy is vital for high‑availability systems where data loss could lead to process upsets or safety risks.

Engineered for universal field device interoperability, the FBM39 natively supports HART and Foundation Fieldbus protocols, enabling seamless connection with smart transmitters, valve positioners, and other intelligent field instruments. It also accommodates Modbus RTU/TCP/IP and Ethernet/IP for integration with third‑party devices, reducing the need for protocol converters and simplifying system architecture. This multi‑protocol flexibility makes it a versatile choice for mixed‑vendor automation environments.

Equipped with a high‑speed processor, the FBM39 delivers sub‑50‑millisecond fault response time for real‑time anomaly detection and resolution. Comprehensive onboard diagnostics continuously monitor communication health, transceiver status, signal integrity, and power supply conditions, alerting the DCS to faults before they escalate. This proactive diagnostic capability minimizes unplanned downtime and supports predictive maintenance strategies.

The FBM39 incorporates embedded safety logic circuits to enhance operational security, particularly in explosive or hazardous industrial zones such as oil and gas processing plants and refineries. Certified for ATEX (hazardous location) compliance, it meets stringent safety standards for use in Class I, Division 2 environments, ensuring safe and reliable operation in high‑risk settings.

Supporting hot‑swap installation and replacement, the FBM39 allows online maintenance without shutting down the process or disrupting other I/O modules. It accepts redundant 24 VDC power inputs, ensuring continuous operation if one power source fails. Communication with Foxboro FCP/ZCP controllers uses a redundant 2 Mbps HDLC fieldbus with automatic path failover, further maximizing system uptime for critical processes.

Constructed with a conformal‑coated PCB and a heavy‑duty industrial housing, the FBM39 is certified for CE, UL, CSA, and ISA S71.04 Class G3 (harsh environment) compliance. It operates reliably in temperatures from ‑20 °C to +60 °C, 5%–95% non‑condensing humidity, and moderate vibration/shock conditions. The compact form factor enables high‑density mounting on standard Foxboro I/A Series backplanes, saving valuable cabinet space.

Manufacturer: Foxboro (Invensys, now Schneider Electric)Compatible Systems: Foxboro I/A Series DCS, EcoStruxure Foxboro (Foxboro Evo™) DCSModel/Part Number: FBM39Module Type: Redundant fieldbus communication interface moduleCommunication Protocols: HART, Foundation Fieldbus, Modbus RTU/TCP/IP, Ethernet/IPTransceivers: Dual redundant fieldbus transceiversData Loss Protection: Zero‑data‑loss transmission frameworkDiagnostic Response Time: <50 ms fault detection and reportingIsolation: Channel‑to‑ground isolation; 600 V AC for one minute withstand ratingPower Supply: 24 VDC (+5%/–10% tolerance), redundant inputPower Consumption: Max 3.0 WOperating Temperature: ‑20 °C to +60 °CStorage Temperature: ‑40 °C to +85 °CRelative Humidity: 5%–95% non‑condensingVibration: 0.1 g rms, 5–500 HzShock: 10 g, 20 ms half‑sineDimensions (W × H × D): Approximately 45 mm × 114 mm × 98 mmWeight: Approximately 0.55 kgCertifications: CE, UL, CSA, ATEX, ISA S71.04 Class G3Reliability Features: Dual redundant transceivers; redundant power/communication; zero data loss; hot‑swap capable; embedded safety logic; comprehensive diagnostics.

The FBM39 is purpose‑built for high‑reliability fieldbus communication in critical industrial processes, where uninterrupted data flow and hazardous area safety are non‑negotiable.

In oil and gas—including refineries, gas processing plants, and offshore platforms—it connects HART‑enabled pressure/temperature transmitters, flow meters, and valve controllers to the DCS, supporting pipeline monitoring, wellhead automation, and flare system control. The redundant design ensures continuous data acquisition in remote, harsh environments.

In chemical and petrochemical plants, it links Foundation Fieldbus devices for reactor, distillation column, and heat exchanger control, delivering precise real‑time data for batch and continuous processes. The embedded safety logic enhances protection in explosive chemical environments.

In power generation (thermal, combined‑cycle, and cogeneration plants), the FBM39 interfaces with smart transmitters for boiler, turbine, and generator monitoring, ensuring stable operation and rapid fault response. The high‑speed diagnostics support condition‑based maintenance for critical equipment.

In water and wastewater treatment, it connects HART level, flow, and pH transmitters for process monitoring and regulatory compliance, withstanding moisture and chemical exposure in treatment facilities.

In pipeline automation, the FBM39’s zero‑data‑loss framework guarantees the integrity of real‑time sensor data across vast pipeline networks, supporting leak detection, pressure control, and remote monitoring for oil, gas, and water pipelines.

The FBM39 mounts directly on standard Foxboro I/A Series backplanes inside DCS cabinets, connecting to dedicated baseplates for backplane power and redundant HDLC fieldbus communication. Field wiring terminates at mating termination assemblies (TAs) equipped with screw terminals, per‑channel fuses, and surge protection devices to safeguard against voltage spikes and electrical interference. TAs support shielded fieldbus cables to minimize noise in electrically harsh environments.

Configuration is performed via Foxboro DCS software: select communication protocol (HART/Foundation Fieldbus), configure redundant transceiver paths, set diagnostic thresholds, and map field devices to DCS tags. The module is plug‑and‑play compatible with existing Foxboro systems, supporting hot‑swap replacement to minimize downtime. For high‑availability applications, redundant power supplies and communication paths can be configured to ensure uninterrupted data transmission.

Routine maintenance includes visual inspection for physical damage, loose connections, or dust buildup on the module and termination assemblies, and verification of front‑panel LEDs for normal power and communication status. Periodic testing of transceiver redundancy, diagnostic functionality, and signal integrity is recommended, especially in high‑vibration or corrosive environments. The conformal‑coated PCB reduces cleaning frequency and protects against moisture, dust, and chemical contaminants.

Faulty modules can be repaired by authorized Schneider Electric service providers, with standard repair options available. The FBM39 comes with a 12‑month standard warranty against manufacturing defects, with extended warranty options available for long‑term operational reliability.