Yokogawa ALR121-S50 Serial Communication Module

Product Description

The Yokogawa ALR121-S50 is a dual-channel RS-422/RS-485 serial communication module for Yokogawa CENTUM VP DCS and ProSafe-RS SCS safety systems. It supports Modbus RTU and other serial protocols, acting as an interface gateway between the FCS controller and third-party field devices such as flow meters, analyzers, drives and PLCs. This S50 suffix is standard non-explosion-proof version, designed for FIO rack installation, and is widely used as spare part for industrial process control system maintenance and upgrade.

Product Functions

• Provide two independent RS-422/RS-485 serial ports for Modbus RTU master/slave communication
• Data exchange between CENTUM VP FCS / ProSafe-RS SCS and external serial instruments
• Built-in communication isolation, error check and frame filtering to resist field EMI interference
• Onboard LED indicators for communication status, link activity and fault diagnosis
• Support hot swap within the FIO rack for convenient replacement without system shutdown
• Real-time serial data forwarding and status upload to the DCS monitoring station

Application Scenarios

• Petrochemical, refining and natural gas CENTUM VP DCS control systems
• ProSafe-RS safety instrumented systems for safety interlock and ESD cabinets
• Power plant boiler, turbine and auxiliary process automation control
• Chemical, water treatment and pharmaceutical continuous production lines
• Spare replacement and repair of existing Yokogawa FIO rack stations

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