ABB TB850 3BSC950193R1 Termination Unit

Product Overview

The TB850 (3BSC950193R1) is a critical communication component designed for the CEX-Bus (Communication Expansion Bus) used in ABB AC 800M controller environments. This hardware terminator is required to maintain signal integrity by preventing electrical reflections at the end of the bus string. Engineered with a rugged 25-pin male interface and integrated screw fixings, the TB850 ensures a secure, vibration-resistant connection, stabilizing data exchange between the CPU and its associated communication expansion modules.

Technical Specifications

• Brand ABB

• Model Designation TB850

• Part Number 3BSC950193R1

• Product Type CEX-Bus Terminator

• Connector Interface 25-pin DB25P (Male)

• Fixing Mechanism Integrated screw-locking for industrial stability

• Application Requirement Mandatory for the final physical unit on a CEX-Bus

• Bus Architecture Compatibility ABB AC 800M / CEX-Bus modules

• HS Code 853690 (Electrical apparatus for connections)

• Customs Tariff Number 85369095

• Width 50 mm

• Height 16 mm

• Depth 55 mm

• Net Weight 0.04 kg

• Cable Length 0 m (Direct-connect plug)

Engineering Insights and Operational Logic

The TB850 (3BSC950193R1) is a passive yet essential element in the CEX-Bus physical layer. Without proper termination, the high-speed communication signals within the AC 800M system can suffer from "signal bounce," leading to intermittent bus errors or complete communication failure between the controller and expansion interfaces. By installing the TB850 on the last module in the sequence, the bus impedance is correctly matched. The DB25P male connector is specifically chosen for its high-density contact reliability, while the screw fixings prevent the terminator from loosening due to machine vibrations common in power plant or chemical factory control cabinets.