ABB TU846 Module Termination Unit

The TU846 is a passive Module Termination Unit (MTU) designed for redundant configurations of the CI840/CI840A communication interface and redundant I/O modules. It provides robust field communication connectivity, power distribution, and mechanical protection for industrial automation systems.

General Information

• Article Number: 3BSE022460R1

• Communication Protocol: PROFIBUS DP-V1

• Master or Slave: N/A

• Line Redundancy: Yes

• Module Redundancy: Yes

• Hot Swap Capability: No

• Power Input: 24 V DC (range: 19.2 – 30 V)

• Mounting Orientation: Vertical or Horizontal

Functional Description

• Supports redundant operation of two CI840/CI840A modules.

• Connects to two electrical ModuleBuses for dual communication paths.

• Includes two rotary switches (0–99) for station address configuration.

• Allows connection of ModuleBus Optical Port TB842 via TB846.

• Equipped with mechanical keying to prevent incorrect module insertion.

• Designed with latching mechanism for secure DIN rail mounting and grounding.

• Not hot-swappable – must be powered down before replacement.

• Requires clearance space on the left side for removal.

• Maximum ModuleBus length from TU846 to the bus terminator: 2.5 meters.

Mechanical Keying System

• Four mechanical keys (two per CI840/CI840A position).

• Each key has six positions, enabling 36 unique configurations.

• Mechanical configuration only — does not affect functionality of modules.

Features & Benefits

• Redundant support for CI840/CI840A and I/O modules

• Power supply connection integrated into MTU

• Two PROFIBUS DP-V1 communication interfaces

• Two service tool ports for configuration and diagnostics

• Dual rotary switches for station address setting (0–99)

• ModuleBus Optical Port connector via TB846

• Mechanical keying system to prevent incorrect module installation

• DIN rail mounting with latching for secure attachment and electrical grounding