Description
Core Product Summary
The Foxboro FBM218 is an 8-channel HART communication redundant output interface module engineered for use within Foxboro I/A Series and EcoStruxure Foxboro Distributed Control System (DCS) architectures. It is designed to provide high-availability control by accepting pairs of modules configured for level-FBM redundancy, outputting standard 4 to 20 mA analog control signals with simultaneous digital HART Frequency Shift Keying (FSK) communication.
Each channel features an individual channel-isolated output and a dedicated FSK modem, allowing bi-directional digital communications with HART-compliant field actuators, valves, and positioners (supporting versions 5, 6, and 7) without disrupting primary control loops. Powered by redundant 24 V DC inputs and connected across a dual 2 Mbps HDLC fieldbus, the FBM218 ensures fault-tolerant process execution in demanding industrial plants.
Key Technical Specifications
| Specification Parameter | Verified Value / Detail |
| Product Type | 8-Channel HART Redundant Output Interface Module |
| System Family | Foxboro I/A Series / EcoStruxure Foxboro DCS (200 Series I/O) |
| Output Channels | 8 individually isolated output channels |
| Supported Signal Formats | Standard 4 to 20 mA DC analog output; Superimposed digital HART FSK (HART 5, 6, and 7) |
| Dedicated Channel Modems | 1 FSK modem per output channel for concurrent HART digital messaging |
| Analog Accuracy | ±0.05% of span (between 4 mA and 20 mA) |
| Output Load Capacity | 750 Ω maximum |
| Digital Update Rate | 2 messages per second per device |
| Redundancy Architecture | FBM-level pairing (Master/Tracker configuration via redundant adapter) |
| Module Power Supply Input | Redundant 24 V DC (+5%, -10%) |
| Power Consumption / Dissipation | 7 W to 8 W maximum consumption / 4 W to 5 W heat dissipation |
| Isolation Rating | Withstands 600 V AC for 1 minute between isolated channels and ground |
Detailed Product Overview
The Foxboro FBM218 acts as a critical control gateway for HART-enabled field final control elements. By pairing two identical modules in adjacent slots on a modular baseplate with a specialized redundant adapter, the system achieves true FBM-level redundancy. One module functions as the active Master while the other acts as a synchronized Tracker; if the primary module encounters a fault or diagnostic failure, its outputs drop safely to 0 mA while the tracking module instantly maintains loop current continuation to the field.
Every channel includes independent galvanic isolation and a dedicated FSK modem, protecting system logic from field-level electrical transients while enabling continuous device configuration, calibration checks, and diagnostics gathering. System configuration parameters—such as fail-safe fallback actions and fieldbus failure timeout delays—are managed directly from the host engineering environment.
System Compatibility & Integration Requirements
| Item / Dependency | Verified Compatibility or Requirement | Practical Note |
| Control System Platform | Foxboro I/A Series DCS / EcoStruxure Foxboro DCS | Requires base system software supporting 200 Series I/O subsystems. |
| Mounting Infrastructure | Standard or Compact 200 Series modular baseplates | Requires adjacent slots (e.g., 1-2, 3-4) and a matching redundant adapter kit for high-availability setups. |
| Termination Assemblies (TAs) | DIN-rail mounted TAs (Compression or Ring-Lug styles) | Interfaced via standard subsystem transition cables (up to 30 meters) terminating at a common TA for the module pair. |
| Environmental Enclosure | Certified for harsh environments up to ISA Standard S71.04 Class G3 | Ruggedized extruded aluminum exterior protects internal circuitry in corrosive plant conditions. |
FBM218
FBM218
Dimensions, Mounting & Connection Notes
- Form Factor: Modular plug-in card featuring a durable extruded aluminum housing designed for standard baseplate mounting slots.
- Mounting Options: Baseplates mount onto horizontal/vertical DIN rails or inside 19-inch equipment racks using dedicated mounting kits.
- Wiring Termination: Field output loops route through a single shared DIN-rail mounted Termination Assembly connected via a redundant adapter cable.
- Hot-Swapping Support: Designed to permit online replacement of a failed module within a redundant pair under power without disturbing active field wiring or process loops.
FAQ
What is the primary function of the Foxboro FBM218?
The Foxboro FBM218 is an 8-channel HART communication redundant output interface module that supplies 4 to 20 mA control signals and simultaneous digital HART data to field actuators while supporting module-level redundancy.
How does module-level redundancy operate on the FBM218?
Two FBM218 modules are placed in adjacent baseplate slots and linked via a redundant adapter to a single termination assembly. One module acts as the Master and the other as the Tracker; if the Master fails diagnostics, it drops to 0 mA while the Tracker automatically sustains loop control.
Does the FBM218 support non-HART analog control valves?
Yes. Each channel can independently drive standard non-HART 4 to 20 mA analog devices as well as HART-compliant smart instruments.
What HART protocol versions are supported by the module?
The module natively supports field instruments compliant with HART protocol versions 5, 6, and 7.
Can the FBM218 be replaced while the industrial process is running?
Yes, the redundant architecture and hot-swappable baseplate design allow a faulty module to be extracted and replaced live without interrupting process output loops.
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