ABB TU842 3BSE020850R1 S800 I/O Redundant Module Termination Unit

Description

The TU842 is a Module Termination Unit (MTU) designed for the S800 I/O system to support redundant I/O configurations. It serves as the physical and electrical interface base, enabling two compatible S800 I/O modules to work in pairs for high-availability process automation applications. Engineered with a maximum voltage rating of 50V, this unit routes signal and power lines safely while facilitating horizontal DIN rail mounting inside electrical control cabinets.

Features

• Built for redundant I/O module pairing to eliminate single points of failure.
• Rated for signal and power distribution up to 50V maximum.
• Formed for horizontal mounting orientation on standard industrial DIN rails.
• Streamlines field wiring termination to improve system maintainability.
• Integrated keying mechanisms prevent the accidental insertion of mismatched I/O modules.

Applications

• Distributed Control Systems (DCS) requiring high-availability configurations.
• Critical process loops in chemical plants, oil refineries, and water treatment utilities.
• Power generation plant safety and auxiliary control setups.
• Factory automation control systems utilizing the S800 I/O architecture.

Technical Specifications

Installation Guidelines

DIN Rail Mounting

Mount the unit horizontally on a top-hat standard 35 mm DIN rail. Ensure the rail is grounded properly to the backplate of the enclosure to manage electromagnetic interference. Snap the locking clips securely onto the rail to avoid movement under vibration.

Wiring and Signal Insulation

Verify that all field wiring routed to the terminal connections does not exceed the maximum specification of 50V. Maintain proper separation between low-voltage signal cables and high-power electrical runs within the cable ducting.

Redundant Module Matching

When seating modules into the dual slots of the base unit, ensure that both components are of identical model numbers and firmware revisions to maintain proper synchronization and failover functions.

Heat Dissipation

Keep appropriate open space above and below the horizontally installed base unit. Proper spacing prevents stagnant hot air pockets and guarantees sufficient natural convection across the module housings.

FAQ

What is the core purpose of the TU842 base unit?

It provides the shared electrical connection points and mechanical mounting slots required to operate two S800 I/O modules in a redundant configuration.

What is the maximum operational voltage supported by this termination unit?

The unit is specified for a maximum operating voltage of 50V.

Can this unit be mounted vertically on the DIN rail?

No, this module termination unit is explicitly designed for horizontal DIN rail mounting.

Does this product incorporate any batteries?

No, the unit contains zero batteries and depends entirely on external system power distribution.

Which ABB control architectures support this device?

It is fully compatible with ABB System 800xA versions 4.0 through 6.0 and the Compact Product Suite running S800 I/O modules.