ABB TU843 3BSE021443R1 S800 I/O Redundant Module Termination Unit

Description

The TU843 is a specialized Module Termination Unit (MTU) engineered for integration with redundant I/O modules within the ABB S800 I/O ecosystem. It acts as the mechanical and electrical anchoring base for dual I/O modules, establishing a robust interface that enables hot-swapping and seamless failover configurations in critical industrial processes. The base facilitates all field wiring connections and internal ModuleBus pass-through channels without breaking signal continuity during servicing.

This specific unit is configured for vertical DIN rail mounting, allowing control engineers to optimize cabinet layout and high-density tracking. Functioning safely within a low-voltage spectrum up to 50V, the unit manages discrete, analog, and communication loop distribution lines across automated control infrastructures managed by broader decentralized control networks.

Features

• Built exclusively to house dual redundant S800 I/O modules
• Vertical DIN rail mounting topology for specific cabinet orientations
• Simplifies field signal routing via built-in terminal blocks
• Supports hot-swapping of inactive or faulted modules under power
• Verified operational threshold up to 50V

Applications

• Distributed Control Systems (DCS) deployments featuring ABB System 800xA
• Compact Product Suite automation setups requiring space-saving form factors
• High-availability process loops in petrochemical, marine, and power facilities
• Mission-critical safety or auxiliary monitoring stations requiring redundant failover paths

Technical Specifications

Installation Guidelines

• DIN Rail Mounting: Snap the assembly firmly onto a standard 35mm vertical DIN rail. Ensure the rail is bonded to the main enclosure earth ground system.
• Cabinet Orientation: Verify the mounting orientation matches the vertical layout requirement to satisfy default convective airflow pathways around operational modules.
• Wiring Practice: Terminate field cables utilizing proper wire ferrule dimensions, taking care to segregate low-voltage instrument loops from adjacent higher-voltage power distribution runs.
• Module Handling: When inserting or extracting an I/O module from either slot, use even pressure to avoid skewing the multipin backplane connection pins.

FAQ

What is the core difference between the TU842 and the TU843 termination units?

The primary difference is the physical mounting layout. The TU842 is configured for horizontal DIN rail mounting, whereas this unit is structurally designed for vertical DIN rail installations.

Does this MTU require an isolated external grounding strap?

The device grounds through its DIN rail attachment, though following standard cabinet grounding practices by maintaining a low-impedance connection to the main backplate is required.

Can I run standard 120V AC control loops directly through this termination block?

No, this termination unit has a maximum rated technical voltage of 50V. Exceeding this limit compromises the safety and operational constraints of the device.

Are there internal batteries that require scheduling for maintenance replacement?

No, this passive termination unit contains zero batteries and relies entirely on external system bus architectures for operational logic.

What versions of the ABB 800xA control platform are compatible with this unit?

It is cataloged for compatibility with S800 I/O versions 4.0, 4.1, 5.0, 5.1, and System 800xA 6.0 setups.