FOXBORO FBMSSW CV3-SSW Redundant I/A System Switch Module

FBMSSW (CV3-SSW) is a dedicated redundant communication switch module under FOXBORO I/A Series DCS, originally developed by Invensys and now owned by Schneider Electric. It serves as the core signal bridge between DCS controllers and field I/O modules, supporting dual redundant I/A Highway (IAH) and HSR high-speed bus transmission, automatically switching communication channels once single line fault occurs to avoid system monitoring interruption. The module provides ±15V isolated power supply interfaces and LVDT signal terminals for auxiliary sensor signal conditioning inside control cabinets.

This compact DIN rail plug-in unit adopts full metal heat sink shell with industrial anti-corrosion coating, featuring built-in CRC error correction and real-time communication fault diagnosis. It is widely used as maintenance spare parts for legacy FOXBORO I/A DCS systems in petrochemical, power plant and pulp & paper industries, compatible with all CV3 series rack I/O modules and workstation controllers.

Main Specifications

• Brand: FOXBORO (Invensys/Schneider); Model: FBMSSW; Type Code: CV3-SSW
• Applicable System: FOXBORO I/A Series Distributed Control System
• Bus Protocol: I/A Highway (IAH), HSR High Speed Redundant communication bus
• Switching Speed:<10ms automatic redundant channel switching
• Power Interfaces: Onboard ±15V DC isolated power output terminals for peripheral sensors
• Signal Terminal: LVDT sensor signal input port, D/S/R bus communication terminals
• Error Detection: Built-in CRC data error correction, real-time communication loss alarm
• Operating Temperature: -40℃ ~ +70℃; Storage Temp: -40℃ ~ +85℃
• Humidity Range: 5%~95% RH non-condensing, high EMC anti-interference performance
• Installation: Standard DIN rail mounting, compact vertical heat sink housing
• Matching Hardware: CV3 series I/O cards, FOXBORO CP40/CP60 controllers, I/A Series workstation panels

Core Functions

• Establish dual independent redundant I/A Highway communication links between DCS main controllers and field I/O racks, transmitting real-time process data and control commands bidirectionally.
• Execute fast automatic channel switching within 10ms when primary communication bus breaks down, ensuring uninterrupted data transmission and stable closed-loop process control.
• Supply isolated ±15V DC auxiliary power and signal conditioning for LVDT displacement sensors and small field transmitters installed in control cabinets.
• CRC error checking circuit filters transmission noise and data distortion generated by high-power equipment, improving bus communication stability in heavy electromagnetic industrial environments.
• Real-time self-diagnosis monitors bus disconnection, power supply abnormality and internal hardware faults, uploading fault codes to upper DCS operation station for troubleshooting.
• Unified CV3 rack bus definition supports direct ｄｒｏｐ-in replacement without modifying cabinet wiring or DCS control configuration parameters during equipment overhaul.

Application Scenarios

• Redundant communication switch spare replacement for FOXBORO I/A Series DCS control racks in thermal power plants and hydropower stations.
• Bus signal bridge maintenance spare parts for petrochemical refineries, natural gas processing plants and pulp & paper mill legacy automation systems.
• Backup inventory for metallurgical steel plants, cement kilns and chemical fertilizer factory I/A DCS cabinet overhaul projects.
• Matching communication module cooperating with FOXBORO CP60 controller, CV3 analog/digital I/O boards and local operation HMI panels.
• Retrofit spare components for aging I/A DCS racks suffering from communication jitter, single bus failure and unstable sensor power supply faults.

• Global aftermarket spare stock for process industry maintenance workshops maintaining vintage FOXBORO Invensys DCS hardware.