ABBITU844 3BSE02445R1|Redundant Module Termination Unit

Product Description

The TU844 (3BSE021445R1) is a high-availability redundant Module Termination Unit (MTU) engineered for the ABB S800 I/O system. This critical hardware component provides the physical and electrical foundation for hosting two redundant I/O modules, ensuring continuous process monitoring even during a single module failure. Designed for horizontal DIN rail installation, the TU844 manages the distribution of the ModuleBus and process power to the redundant pair. It is specifically optimized for analog input applications, such as those using AI845 or AI880 modules, where signal continuity is paramount for industrial safety and efficiency.

Technical Specifications

• Manufacturer: ABB

• Model Number: TU844

• Part Number: 3BSE021445R1

• Product Type: Redundant Module Termination Unit

• Configuration: Dual-module redundancy (1+1)

• Mounting Orientation: Horizontal DIN rail

• I/O Connectivity: Supports redundant signal and power distribution

• Shunt Support: Designed for use with TY801 shunt sticks (sold separately)

• Mechanical Latching: Integrated secure DIN rail locking mechanism

• Width: 124 mm

• Height: 186.5 mm

• Depth: 64 mm

• Net Weight: 0.6 kg

• Environmental Tolerance: Designed for standard industrial cabinet temperatures

System Integration & Redundancy Logic

The TU844 serves as the junction point for redundant I/O clusters. It permits two identical I/O modules to be inserted side-by-side, sharing the same field wiring terminals. The MTU internally handles the "voting" or switching logic (depending on the module type) to ensure that if the primary module reports a fault, the secondary module seamlessly maintains the process values. This architecture is essential for applications requiring High Integrity or mission-critical uptime.