ABB TU846 3BSE022460R1 S800 I/O Module Termination Unit

Description

The TU846 is a Module Termination Unit (MTU) designed for the S800 I/O system. It provides the physical housing, electrical connections, and termination points for two CI840 Fieldbus Communication Interfaces in a 1+1 redundant configuration. This unit enables redundant I/O capabilities and is engineered for vertical mounting within control cabinets to optimize space and thermal management. The unit distributes power and internal Modulebus signals to the hosted communication modules while maintaining complete electrical isolation and signal integrity.

Features

• Supports dual CI840 modules for fully redundant fieldbus communication.
• Designed for vertical DIN-rail mounting to facilitate efficient cabinet layout.
• Includes one dedicated power supply connector for secure input distribution.
• Equipped with two TB807 Modulebus Terminators to ensure correct bus impedance.
• Built-in mechanical keying prevents the insertion of incorrect module types.

Applications

• Distributed Control Systems (DCS) and Programmable Logic Controllers (PLC).
• Process automation industries including oil and gas, chemical, and water treatment.
• High-availability power generation and electrical distribution control systems.
• Factory automation environments requiring redundant I/O infrastructure.

Technical Specifications

Installation Guidelines

DIN Rail Installation

Mount the termination unit vertically onto a standard 35 mm DIN rail. Ensure the rail is properly grounded to the cabinet enclosure. Engage the top DIN rail clip first, then press the lower portion of the unit firmly against the rail until the locking mechanism clicks into place.

Power Connection

Connect the system power supply using the included power supply connector block. Verify that the input voltage complies with the requirements of the hosted communication modules before energizing the circuit. Ensure proper polarity is maintained to prevent component damage.

Modulebus Termination

The two included TB807 Modulebus Terminators must be installed at the designated ends of the internal bus segment. Correct termination is required to eliminate signal reflections and maintain reliable communication across the S800 I/O structure.

Cooling and Ventilation

Maintain adequate clearance above and below the vertically mounted unit to allow natural convective airflow. Do not block the ventilation paths of the hosted modules, as proper thermal dissipation prevents localized overheating.

FAQ

What is the primary function of the TU846 unit?

It acts as a physical base and electrical interface that supports two fieldbus communication modules in a redundant configuration for the S800 I/O system.

Does this module termination unit come with the necessary terminators?

Yes, the package includes two TB807 Modulebus Terminators along with one power supply connector.

Can this unit be mounted horizontally on a DIN rail?

No, this specific model is designed exclusively for vertical mounting to ensure proper module alignment and optimal heat dissipation.

Which specific communication module is compatible with this MTU?

It is explicitly designed to host the CI840 Fieldbus Communication Interface in a 1+1 redundant setup.

Is any special tool required to secure the power supply connector?

Standard industrial screwdrivers matching the terminal block screws are sufficient to secure the incoming power wiring.

What control systems support this equipment?

It is compatible with ABB System 800xA (versions 4.0 through 6.0) and the Compact Product Suite utilizing S800 I/O.