Industrial automation has evolved from simple relay logic to sophisticated distributed control systems. As factories demand higher reliability, redundancy in communication networks becomes critical. The ABB TU849 termination unit addresses this need by providing a robust interface for redundant Optical ModuleBus modems.
Introducing the TU849 Termination Unit
The ABB TU849, with article number 3BSE042560R1, is a module termination unit (MTU) designed for redundant configurations of the TB840/TB840A Optical ModuleBus Modem. This passive unit connects a single electrical ModuleBus to two modems, supporting dual power supply inputs for enhanced reliability. It includes a rotary switch for cluster address setting from 1 to 7, allowing straightforward system addressing.
Mechanical keying prevents insertion of the wrong module type, with 36 different combinations available via four keys. The unit mounts on a standard DIN rail and features a mechanical latch for secure locking and grounding. This design simplifies installation and maintenance in control cabinets.
Technical Specifications and Performance
The TU849 operates on a 24 V d.c. power input with a range of 19.2 to 30 V. It distributes ModuleBus current at a maximum of 5 V at 1.5 A and 24 V at 1.5 A. Power dissipation is rated at 2.5 W, ensuring efficient operation within its thermal limits.
Acceptable wire sizes include solid and stranded conductors from 0.2 to 2.5 mm² (24 to 12 AWG), with a recommended torque of 0.5 Nm. The rated insulation voltage is 50 V, and the dielectric test voltage is 500 V a.c. These specifications ensure safe and reliable electrical connections in industrial environments.
The unit measures 124 mm in width, 186.5 mm in height including the latch, and 47 mm in depth. It weighs 0.45 kg. The operating temperature range is 0 to +55 °C, with approvals issued for +5 to +55 °C. Storage temperature spans -40 to +70 °C. Relative humidity tolerance is 5 to 95%, non-condensing. The ingress protection rating is IP20 according to IEC 60529.
Applications in Modern Manufacturing
In process industries such as chemical plants or refineries, redundant communication links are essential to prevent production stoppages. The TU849 connects TB840/TB840A modems to non-redundant I/O, providing a single ModuleBus connection with dual power supplies. This setup ensures that if one modem or power source fails, the system continues operating without interruption.
For example, in a typical oil and gas pipeline monitoring application, the TU849 supports continuous data transmission between field instruments and the control room. The rotary switch simplifies cluster address configuration, reducing commissioning time. The mechanical keying prevents accidental insertion of incompatible modules, enhancing system safety.
Real-World Application Example
Consider a water treatment facility that requires high availability for its distributed control system. By deploying the TU849 with redundant TB840/TB840A modems, engineers achieve a single I/O path with dual power feeds. This configuration minimizes the risk of a single point of failure, supporting 24/7 operations. The DIN rail mounting and latch mechanism allow quick installation and replacement without tools.
Compatibility and Integration
The TU849 uses the ModuleBus communication protocol, making it compatible with ABB's AC 800M and other controllers that support this interface. It works with both TB840 and TB840A modems, offering line redundancy for critical applications. The unit supports vertical or horizontal mounting, providing flexibility in cabinet layout. For integration, ensure the cluster address is set correctly using the rotary switch and that mechanical keys match the module type.
Why Choose CtrlTechDaily
CtrlTechDaily provides genuine ABB automation components with verified specifications. We stock the TU849 termination unit and can assist with lifecycle status inquiries. Contact our team for pricing and availability to support your next industrial project.
Frequently Asked Questions About the TU849
What is the primary function of the ABB TU849?
The TU849 is a module termination unit for redundant configuration of Optical ModuleBus Modem TB840/TB840A. It provides a single electrical ModuleBus connection, dual power supply inputs, and a rotary switch for cluster address setting.
What are the power requirements for the TU849?
The TU849 requires a 24 V d.c. power input with a range of 19.2 to 30 V. It distributes ModuleBus current at maximum 5 V 1.5 A and 24 V 1.5 A. Power dissipation is 2.5 W.
Does the TU849 support hot swapping of modules?
No, the TU849 does not support hot swap. The data explicitly states "Hot Swap No." Always power down the system before inserting or removing modules to avoid damage.
What certifications does the TU849 hold?
The TU849 carries CE marking, electrical safety certifications per EN 61010-1 and UL 61010-1, hazardous location approvals (cULus Hazardous Location class 1 Zone 2, ATEX Zone 2), and marine certificates from ABS, BV, DNV-GL, and LR. It also complies with EU, UAE, and CN RoHS, and WEEE directive 2012/19/EU.
How do I set the cluster address on the TU849?
Use the rotary switch on the unit to set the cluster address from 1 to 7. The switch is accessible with a screwdriver. Ensure the address is unique within the ModuleBus network to avoid conflicts.
Conclusion
The ABB TU849 termination unit delivers a reliable, redundant interface for Optical ModuleBus modems in industrial automation. Its dual power supply, mechanical keying, and DIN rail mounting simplify deployment while enhancing system availability. For engineers seeking a robust solution for redundant I/O configurations, the TU849 offers proven performance. Contact CtrlTechDaily to verify lifecycle status and place your order.
