Product Details:

FOXBORO FBM20/21 is a piggyback discrete input assembly for FOXBORO I/A Series DCS system, made up of FBM20 main dry contact input card and FBM21 stacked expansion module. It collects passive dry contact status signals from field equipment, including breaker auxiliary contacts, safety interlock switches and local status feedback switches. FBM21 piggyback card extends the total input channels, and all data communication with DCS controller runs through FBM20 over redundant HDLC fieldbus. This module set adopts galvanic channel isolation and conformal coated PCB, protecting electronic components from vibration, dust, humidity and electromagnetic interference in harsh industrial environments. Built-in continuous self-diagnosis detects contact circuit faults and communication errors, triggers alarms to help maintenance staff locate abnormal contact loops quickly and reduce plant downtime. FBM20/21 supports hot swap and is widely used for DCS maintenance, spare parts replacement and system retrofit projects. Every FOXBORO FBM20/21 module set passes factory testing and calibration before shipment.

Specifications:

Model:FBM20/21

Brand:FOXBORO

Product Type:Piggyback Contact Input Assembly Module

System compatibility:FOXBORO I/A Series DCS

Matching main module:FBM20

Input signal:Dry contact discrete input, expandable channels

Communication:Communicate via FBM20 over redundant HDLC fieldbus

Redundancy:Support redundant module configuration

Diagnosis:Built-in self-diagnosis,contact circuit fault detection

Power supply:26~42VDC

Hot swap:Supported

Ambient working temperature:0℃ ~ +60℃

Relative humidity:5% ~ 95%,non-condensing

Installation:Piggyback mount on FBM20 baseplate

Environmental grade:G3 harsh environment,conformal coating

This stacked FBM20/21 combination maximizes contact input density within one rack slot, eliminating the need for extra card slots when expanding passive contact monitoring points. It works without external field power, making it perfect for safety interlock status feedback circuits where isolation is critical. It is commonly used for boiler interlock status monitoring and safety shutdown system auxiliary feedback on process plants, and can directly replace aging piggyback contact input assemblies on legacy I/A DCS systems. Every FOXBORO FBM20/21 module set passes factory testing and calibration to guarantee reliable process control performance.