ABB RMU811｜Repeater Mounting Unit｜

RMU811

ABB RMU811 is a Repeater Mounting Unit / Module Termination Unit used in the ABB Ability™ Symphony® Plus SD Series I/O system. It is a mounting base designed to install and connect redundant RFO810 fiber optic repeater modules for extending the HN800 I/O bus over fiber optic links.

Product Identification
Item Description
Manufacturer ABB
Model RMU811
Product Type Repeater Mounting Unit (RMU) / Module Termination Unit
System Family ABB Ability™ Symphony Plus
Application RFO810 fiber optic repeater mounting
Communication System HN800 I/O Bus
Installation DIN rail / cabinet mounting
Configuration Supports redundant repeater pair

Main Function

The RMU811 itself is a passive mounting base, not an active communication device. It provides the mechanical and electrical interface required for installing two RFO810 fiber optic repeater modules in a redundant configuration.

Main functions:

Holds redundant RFO810 fiber optic repeater modules
Provides 24 VDC power distribution to repeater modules
Provides HN800 bus connection interface
Simplifies cabinet installation and wiring
Enables redundant optical communication architecture
Verify before ordering:
Exact module: RMU811
Installed repeater type: RFO810
Symphony Plus hardware generation
Cabinet wiring and HN800 topology
Redundant or non-redundant configuration
Failure impact:

Because RMU811 provides the physical mounting and interconnection path, a defective unit may cause:

Loss of RFO810 power connection
Fiber repeater communication failure
HN800 remote I/O communication alarms
Loss of redundant communication path
Supply Chain Classification
Category Details
Industry Industrial Automation / DCS
Vendor ABB
System Symphony Plus
Component Type Communication Infrastructure Hardware
Criticality Medium–High
Replacement Strategy Replace complete mounting assembly
Repairability Normally replaced, not repaired