Description

Technical Specifications

• Part Number: RLM02, Order Code: 3BSE091723R1
• Brand: ABB (Origin: Sweden)
• Warranty: One Year
• Module Type: PROFIBUS DP/FMS Redundancy Link Active Switch Module
• Power Supply: 24 VDC, rated current 120mA, max power consumption 2W
• Communication Interfaces: 3 isolated RS485 ports (Port A / Port B redundant bus, Port M single device bus), 9-pin D-SUB connectors
• Baud Rate Range: 9.6 kbps ~ 12 Mbps (fully compliant with IEC 61158-2 PROFIBUS standard)
• Bus Capacity: Each port supports up to 31 PROFIBUS slave devices; expandable via repeaters and fiber media converters
• Isolation: Full galvanic isolation between A/B/M three bus ports and power supply
• Operating Temperature: 0°C ~ +55°C
• Storage Temperature: -30°C ~ +85°C
• Protection Class: IP20 (DIN rail cabinet mounting)
• Diagnostics: Front panel LED status indicators + potential-free relay alarm contact for system fault collection
• Certifications: CE, UL, CSA, DNV GL marine industry approval
• Net Weight: 0.46kg
• 

Product Overview

The RLM02 (3BSE091723R1) is a dedicated PROFIBUS bus redundancy conversion module designed for ABB System 800xA and Freelance DCS distributed control systems. It acts as an intelligent active bus switch to solve the core pain point: most field instruments, valve positioners and drives only have a single PROFIBUS DP interface and cannot be directly connected to dual redundant PROFIBUS backbone networks.

It supports two-way transparent bus conversion:

1. Convert 2 redundant A/B PROFIBUS backbone lines into 1 single M bus to connect non-redundant field devices;
2. Convert 1 single M device bus into dual redundant A/B bus to feed back to the DCS redundant controller.

The module automatically detects frame integrity on Line A and Line B. If one bus fails, it instantly switches data transmission to the healthy redundant channel without interrupting field control logic. It also features built-in signal repeater function to reshape and amplify RS485 bus signals, improving anti-interference performance on long-distance field wiring.

Widely deployed in thermal power plants, petrochemical refineries, offshore marine platforms, chemical process and pulp & paper industries that require high safety and uninterrupted DCS operation. As a critical bus redundancy accessory for ABB 800xA platform, it significantly enhances the fault tolerance and overall availability of the entire PROFIBUS fieldbus control network.