Product Overview

The Foxboro FBM218 (Part Number P0922VW) is a high-availability redundant output interface designed for the I/A Series Distributed Control System (DCS). This module provides eight channels of analog output, specifically engineered to drive final control elements such as valves and actuators using standard 4-20 mA signals. Beyond basic analog control, the FBM218 functions as a sophisticated HART communication host, allowing the DCS to manage and monitor intelligent field devices through bidirectional digital messaging.

Engineered for mission-critical control loops, the FBM218 supports a hardware-redundant configuration. When paired on a compatible baseplate, two modules operate in a Master/Tracker relationship, ensuring that a single module failure does not disrupt the process signal. This seamless failover capability, combined with its rugged industrial build, makes the FBM218 a foundational component for high-reliability process automation.

Technical Specifications

• Manufacturer: Foxboro (Invensys / Schneider Electric)

• Model Number: FBM218

• Part Number: P0922VW

• Module Type: Redundant HART Output Interface

• Output Channels: 8 Group-Isolated Channels

• Signal Output: 4 to 20 mA DC (Analog) + HART Digital FSK

• HART Processing: 2 messages per second per device

• Fieldbus Communication: Dual-redundant 2 Mbps HDLC Fieldbus

• Environmental Rating: ISA S71.04 Class G3 (Harsh)

• Chassis Material: Extruded Aluminum

• Weight: 0.3 kg

• Dimensions: 4.5 x 11.5 x 11.5 cm

Core Technical Characteristics

• Advanced Redundancy Logic: The FBM218 architecture utilizes a redundant Fieldbus interface (Paths A and B). In a redundant pair, the Tracker module mirrors the output of the Master, providing instantaneous takeover of the 4-20 mA signal should the Master module detect an internal fault or loss of communication.

• HART Device Hosting: The module supports universal, common practice, and device-specific HART commands. Each channel serves as a digital gateway, enabling the I/A Series system to perform remote calibration, diagnostics, and parameterization of smart valves and positioners.

• Total Channel Isolation: To ensure maximum signal integrity, each of the eight channels is electronically isolated. This prevents common-mode noise and ground loops from affecting adjacent control loops, effectively localizing electrical faults to a single channel.

• Hardened Industrial Design: Housed in a robust aluminum enclosure, the module is designed for long-term stability in G3-rated harsh environments. It is highly resistant to corrosive gases, humidity, and electromagnetic interference (EMI).

• Deterministic Fieldbus Interface: The module communicates over a 2 Mbps fieldbus with the control processor. This high-speed link ensures that setpoint changes and HART data are processed with the timing precision required for fast-acting control loops.

• Simplified Baseplate Integration: Designed for the modular I/A Series baseplate system, the FBM218 supports hot-swapping and easy physical configuration. Redundant pairs occupy adjacent slots, allowing for a compact and organized cabinet layout.

Primary Applications

The Foxboro FBM218 P0922VW is optimally suited for:

• Critical Valve Positioning: Managing smart positioners in chemical and refinery applications where valve failure is catastrophic.

• Distributed Control Systems: Serving as the primary output interface for large-scale I/A Series and Evo DCS deployments.

• Smart Asset Management: Utilizing HART data for predictive maintenance and remote troubleshooting of field instruments.

• High-Availability Utilities: Boiler and turbine control in power generation facilities requiring redundant output paths.