YOKOGAWA ALR121-S00 Serial Communication Module

YOKOGAWA ALR121-S00 is a 2-port RS-422/RS-485 serial communication module for Yokogawa CENTUM VP DCS FIO/N-IO system. It enables data exchange between the AFV30/AFV40 field control station and third-party subsystems, supporting Modbus RTU and other serial protocols for long-distance field communication.

This module supports point-to-point RS-422 and multi-drop RS-485 half-duplex communication, with a maximum transmission distance up to 1200 meters. It can be mounted on ANB10, ANB11, AFV30 and AFV40 node units, widely used as spare parts to connect PLC, analyzers and weighing instruments in petrochemical and power plants.

Main Specifications

1. Brand: YOKOGAWA; Model: ALR121-S00; Type: Serial Communication Module
2. Compatible System: CENTUM VP DCS; FCS: AFV30, AFV40; Nodes: ANB10, ANB11
3. Interface: Dual RS-422/RS-485 ports; Half-duplex; Baud rate:1200~38400 bps
4. Max distance: 1200m for RS-485 multi-drop; Protocol: Modbus RTU, subsystem serial protocol
5. Power consumption: 0.5A; Weight: approx 0.34kg; Wiring: AKB series shielded cable
6. Operating Temp: -20℃ ~ +70℃; Humidity: 5%~95% non-condensing
7. Supply Status: Spare serial module for CENTUM VP subsystem communication retrofit

Core Functions

1. Provide two RS-422/RS-485 serial ports to connect external third-party devices to CENTUM VP FCS.
2. Support Modbus RTU master/slave communication for data collection from analyzers, weighing units and PLCs.
3. Half-duplex communication, supports RS422 point-to-point and RS485 multi-drop bus topology.
4. Built-in self-diagnosis function to monitor communication status and report link faults to DCS system.
5. Works with ESB bus to transmit acquired serial data to the field control station processor.
6. Standard rack slot installation, convenient replacement during DCS system maintenance.

Application Scenarios

1. Yokogawa CENTUM VP DCS field control station serial communication expansion.
2. Connect DCS with gas analyzers, weighing systems, frequency converters and third-party PLCs.
3. Long-distance multi-point serial signal transmission in petrochemical, chemical and power plants.
4. Replacement of defective ALR121 modules for existing CENTUM VP control cabinets.
5. Spare parts inventory for plant DCS automation maintenance and engineering teams.
6. System retrofit to add Modbus RTU serial communication interface for legacy DCS projects.

FAQ

1. Q: What is YOKOGAWA ALR121-S00?
   A: It is a dual-port RS-422/RS-485 serial communication module for CENTUM VP DCS, used to connect DCS with Modbus RTU subsystems.
2. Q: What is the difference between ALR111 and ALR121?
   A: ALR111 adopts RS-232C interface, while ALR121 uses RS-422/RS-485 for longer distance multi-drop communication.
3. Q: What does suffix S00 stand for?
   A: S stands for standard type, 00 represents basic version without special environmental protection options.