Overview

The ABB TB850 is a compact, screw-mounted terminator used in distributed control systems (DCS) to finalize the CEX-Bus communication line. It features a 25-pin DB25P male connector and is designed for use with ABB’s AC 800M series, including PM864 and PM891 processor units. Moreover, the TB850 plays a critical role in maintaining signal quality by eliminating electrical reflections at the end of the bus. Its passive design requires no external power and offers near-zero power consumption, making it ideal for long-term industrial deployment. In addition, the module complies with international standards for control system accessories and is CE and UL certified.

Technical Data / Specifications

Typical Applications 

The TB850 is essential in ABB AC 800M systems for terminating the CEX-Bus communication line. It ensures reliable data transmission between processor units and communication interfaces in distributed control architectures. For instance, in a power plant or chemical facility, the TB850 is installed at the last node of the CEX-Bus to prevent signal degradation. In addition, it supports integration with various ABB modules such as PM864AK01, CI854A, and other CEX-Bus compatible units. Its simple installation and passive operation make it a preferred choice for system engineers and maintenance teams.

FAQ

Q: What is the function of the TB850 terminator?

A: It terminates the CEX-Bus to prevent signal reflection and ensure stable communication in ABB control systems.

Q: Is external power required for the TB850?

A: No, it is a passive device with near-zero power consumption.

Q: What systems is it compatible with?

A: It is designed for ABB AC 800M systems and works with CEX-Bus modules like PM864 and CI854A.

Q: How is the TB850 installed?

A: It uses a 25-pin DB25P male connector and is fixed with screws at the last unit on the bus.

Q: What are the environmental ratings?

A: Operating temperature is 0°C to +55°C, with IP20 protection for indoor control cabinet use.