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Application Scenarios
In a large power plant DCS upgrade, the existing control cabinet is overcrowded. The new ABB AC800M controller and its S800 I/O modules cannot all fit on a single DIN rail due to space limitations. The engineering team uses the ABB TB805 3BSE008534R1 to solve this. They mount one set of I/O modules on the main rail and a second set on an auxiliary rail in the same cabinet. The TB805 (mounted on the main rail) connects to a TB806 (on the auxiliary rail) via a TK801 extension cable. This extends the ModuleBus electrically, allowing I/O modules on both rails to communicate with the controller as if they were on the same backplane, without requiring an additional controller or complex network configuration.
Parameter
| Main Parameters | Value/Description |
|---|---|
| Product Model | ABB TB805 |
| Manufacturer Part Number | 3BSE008534R1 |
| Manufacturer | ABB |
| Product Type | ModuleBus Cable Adaptor (Bus Outlet) |
| Compatible System | ABB S800 I/O, AC800M, Advant Controller |
| Primary Function | Extends the electrical ModuleBus to remote I/O clusters |
| Connector Type | D-sub 25-pin female (for TK801 extension cable) |
| Mounting | 35mm DIN Rail |
| Dimensions (W x H x D) | 22 mm x 109 mm x 25 mm |
| Weight | 46 g |
| Operating Temperature | 0 °C to +55 °C |
| Storage Temperature | -25 °C to +70 °C |
| Protection Class | IP20 (for enclosure use only) |
| Safety/Certification | CE, UL 61010-1, cULus (HazLoc C1 Div 2/Zone 2), ATEX Zone 2, Marine (ABS, BV, DNV, LR) |
| EMC | EN 61000-6-2, EN 61000-6-4 |
Technical Principles and Innovative Values
The ABB TB805 is a passive interconnection device that extends the life and flexibility of the S800 I/O architecture.
- Innovation Point 1: Cabinet Layout Decoupling. The core innovation of the TB805 is its ability to break the physical constraint of a single DIN rail. It allows an I/O cluster to be split across multiple locations within a cabinet or between adjacent cabinets while maintaining a single, continuous electrical ModuleBus. This eliminates the need for expensive fiber-optic transceivers or additional communication processors for short-distance expansion.
- Innovation Point 2: Signal Integrity Preservation. Despite being a simple adaptor, the TB805 is designed to maintain the integrity of the high-speed ModuleBus signals over extended cable runs (when used with TK801). Its internal layout and connector design minimize signal reflection and crosstalk, ensuring reliable communication between the controller and remote I/O modules.
- Innovation Point 3: Maintenance-Friendly Design. The TB805’s compact and standardized form factor allows for easy installation and replacement. If a section of the I/O rail needs to be serviced, the TB805/TB806 pair allows that section to be electrically isolated via the cable, facilitating easier troubleshooting compared to a monolithic backplane.
Application Cases and Industry Value
Case Study: Chemical Plant Control Cabinet RetrofitA chemical plant was expanding its batch processing line and needed to add 32 new I/O points to an existing AC800M controller cabinet. The main DIN rail was full, and there was no space for a second controller. The solution was to install an auxiliary DIN rail inside the same cabinet. The team installed a TB805 on the main rail and a TB806 on the auxiliary rail, connecting them with a 1-meter TK801 cable. The new S800 I/O modules were then mounted on the auxiliary rail. The TB805 allowed the plant to double the I/O capacity within the same footprint without any software configuration changes, as the system recognized the new modules as part of the same local cluster. This approach saved significant capital expenditure that would have been required for a remote I/O station.
