ABB RMU610 2VAA008425R1 Fiber optic bus module base

I. Basic Model Information
Complete Order Number: RMU610 / 2VAA008425R1
System: ABB Ability Symphony Plus (SD series HN800 high-speed I/O bus)
Equipment Positioning: Dual cRBX01 optical bus module dedicated redundant installation base (Redundant Module Unit)
Companion Kit: HRBX01K02 redundant optical relay kit = 2 cRBX01 optical modules + 1 RMU610 base
Distinguishing Misconception: This RMU610 is not a medium-voltage ring main unit, but a bus base within the DCS cabinet, and has no relation to the distribution RMU ring main unit.

Core Functions
Dual-module redundant carrying
The base has two independent HN800 bus power supplies and backplane links, and can plug in 2 cRBX01 optical relays to achieve 1+1 hot redundancy of optical links; a single optical module failure will automatically switch, and the IO communication will not be interrupted.
HN800 bus power distribution
Powered by the cabinet’s 24VDC, internally isolated, and fed independently to two cRBX01 modules, a single power supply failure does not affect the operation of the other module.
Bus signal synchronous routing
Transparently forwards SPC800 controller HN800 differential bus signals to the optical modules, without software configuration, the controller automatically identifies redundant remote IO links.
Fault diagnosis aggregation
The base integrates a status loop, the power supply, optical link, and bus fault signals of the two cRBX01 are aggregated and uploaded to the system alarm; the panel status indicator lights intuitively display the redundant operation status.
DIN rail standard installation
Compact integrated base, directly clamped onto the 35mm DIN rail of the control cabinet, arranged horizontally, and used in combination with CHBX01L/R horizontal bus expanders.

Model Naming Interpretation
RMU = Redundant Module Unit
610 = Symphony Plus HN800 optical relay dedicated base series
2VAA008425R1: ABB global factory original material order code

Electrical and Mechanical Parameters Table
Parameter Item Specification
Power Input 24VDC ±15%, supplied by the cabinet system power supply
Overall Power Consumption No load: 2W, full load: approximately 8W when paired with two cRBX01 or cRBX01e HN800 optical repeaters
Supported Modules 2×cRBX01 / cRBX01e HN800 optical repeaters
Bus Standard HN800 4Mbps differential high-speed I/O bus
Installation Method 35mm DIN rail horizontal installation
Operating Temperature -10℃ ~ +55℃; Storage: -40℃ ~ +70℃
Protection Grade IP20 (for use in control cabinet)
Environmental Humidity 5%~95% RH, no condensation
Certifications CE, UL, RoHS, IEC61131-2

Hardware Interface Description
Left DB36 bus socket: Connects to the local HN800 host rack / CHBX01L/R horizontal expansion bus, transmits data + 24V power supply
Dual module slots: Two slots on the front and back are used to install the primary and backup cRBX01 optical modules, fixed by snap fastening, supports hot swapping
24V power terminals: Green spring terminals, external cabinet 24VDC power input point
Shielding grounding terminals: Single point grounding terminal for bus shielding, suppresses strong electromagnetic interference in power plants

Hardware Combination
Controller: SPC800, SPC800K02 redundant controller
Optical Module: cRBX01 (multi-mode optical fiber, maximum 3km remote IO)
Local Bus Expansion: CHBX01L (left expansion), CHBX01R (right expansion)
I/O Rack: HN800 standard SD I/O rack (AI830A, AO820, DI810 and other card components)
Optical Cable: OM1/OM4 multi-mode optical fiber, point-to-point star topology