ABB TU841 S800 I/O Redundant Modem Termination Unit
Manufacturer: ABB
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Part Number: TU841
Condition：New with Original Package
Product Type: Module Termination Units
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Country of Origin: Sweden
Payment:T/T, Western Union
Shipping port: Xiamen
Warranty: 12 months
ABB TU841 (3BSE020848R1) S800 I/O Module Termination Unit
The TU841 (Part Number 3BSE020848R1) is a Module Termination Unit (MTU) engineered by ABB for the S800 I/O system within the System 800xA automation platform. It is designed to bridge redundant Optical ModuleBus modems, such as the TB840 and TB840A, with non-redundant I/O modules, enabling fault-tolerant data transmission in distributed control architectures.
System Interconnection and Addressing
The unit provides physical connection points for a primary power supply, one electrical ModuleBus, and dual optical modems to maintain redundant communication pathways. Cluster addressing is configured via an integrated rotary switch supporting positions 1 through 7, allowing precise network node identification within the control framework.
Mechanical Keying and Installation
To prevent incorrect module insertion during maintenance or commissioning, the TU841 incorporates a mechanical keying system using four keys across six available positions, yielding 36 unique keying configurations. Housed in a standard modular enclosure designed for DIN rail mounting, the unit measures 160 mm x 160 mm x 120 mm with a net weight of 0.8 kg.
Technical Specifications
| Parameter | Specification |
|---|---|
| Model | TU841 |
| Part Number | 3BSE020848R1 |
| Manufacturer | ABB |
| Product Series | S800 I/O / System 800xA |
| Product Type | Module Termination Units |
| Primary Function | MTU for redundant TB840/TB840A modems with non-redundant I/O |
| ModuleBus Connections | 1 electrical ModuleBus, 2 optical modems (TB840/TB840A) |
| Cluster Addressing | Rotary switch (positions 1–7) |
| Mechanical Keying | 4 keys (2 per position, 6 positions each, 36 configurations) |
| Mounting Type | DIN rail mounting |
| Dimensions (L x W x H) | 160 mm x 160 mm x 120 mm |
| Weight | 0.8 kg |
| Country of Origin | Germany / Spain / United States |
Frequently Asked Questions
Q: What is the primary application of the ABB TU841 module termination unit? A: The TU841 connects redundant optical ModuleBus modems (TB840 or TB840A) to non-redundant S800 I/O modules, ensuring reliable communication in distributed control systems.
Q: How is cluster addressing configured on this MTU? A: Cluster addresses are set using an onboard rotary switch adjustable from position 1 to 7.
Q: What mechanism prevents improper module insertion? A: The unit features a mechanical keying system with 4 keys across 6 positions, providing 36 distinct configurations to secure correct module placement.