Product Overview

The TU843, cataloged under order reference 3BSE021443R1, is a specialized Module Termination Unit (MTU) designed for the S800 I/O system within the ABB Compact Product Suite. This hardware component serves as the mechanical and electrical interface between field wiring and I/O modules, specifically supporting redundant ModuleBus configurations. It provides a robust platform for 3-wire field instrument connections and manages the distribution of process voltage across 16 independent channels. By facilitating automated module addressing and providing physical keying to prevent incorrect hardware insertion, the TU843 ensures the high-integrity signal path required for Distributed Control System (DCS) reliability.

Hardware Interface Profile and Functional Specifications

The TU843 is engineered for high-density cabinet environments, prioritizing rapid installation and physical protection for the S800 I/O bus.

• Model Identification TU843

• Order Reference 3BSE021443R1

• I/O Capacity Supports up to 16 channels with 3-wire connectivity

• Voltage Rating 50 V Maximum

• Current Capacity 3 A per channel / 10 A total process power

• ModuleBus Support Dual redundant ModuleBus connections (incoming and outgoing)

• Mounting Standard 35mm DIN rail with integrated grounding latch

• Safety Feature Four mechanical keys per unit to enforce correct module type matching

• Physical Weight 0.62 kg

• Unit Dimensions 18.5 x 13 x 6.5 cm

• Manufacturing Origin Sweden

• HS Classification 8537101190

Industrial Deployment and Connectivity Roles

As a fundamental building block for decentralized automation, the TU843 is utilized in sectors where high-availability and simplified field wiring are critical.

• Critical Process Redundancy Managing dual ModuleBus paths to ensure uninterrupted data flow even if one communication branch fails in oil, gas, or chemical processing.

• Streamlined Field Wiring Utilizing 3-wire connections (Signal, +24V, 0V) to eliminate the need for external distribution terminal blocks, reducing cabinet footprint.

• Automated System Addressing Facilitating the automatic position-based addressing of S800 modules by shifting position signals to the next unit in the rack.

• Instrument Protection Providing individual channel isolation and process power distribution for 2-wire and 3-wire sensors or actuators.

• Maintenance Safety Leveraging mechanical keying to ensure that maintenance personnel cannot inadvertently insert a digital module into a slot configured for analog signals.