Product Description

Overview

The ABB TU891 Module Termination Unit (MTU) is a critical component in System 800xA S800 I/O installations, providing reliable signal distribution and field device interfacing. It simplifies wiring between field instruments and I/O modules, while mechanically keying modules to prevent incorrect installation. Moreover, the TU891 supports both standard and intrinsic safety (IS) configurations, ensuring flexible deployment in a wide range of industrial environments.

Technical Specifications

Attribute — Specification
Model Number — TU891
Product ID — 3BSC840157R1
Type — Module Termination Unit (MTU)
System Compatibility — ABB System 800xA S800 I/O modules
Functions — Field signal termination, process voltage connection, ModuleBus distribution, address generation
Rated Voltage — Max 50 V
Rated Current — Max 2 A per channel
Terminal Type — Gray terminals for field signals and process voltage
Bus Distribution — Distributes ModuleBus to I/O module and next MTU
Addressing — Generates correct address by shifting outgoing position signals
Mechanical Keying — Two mechanical keys for IS/non‑IS module configuration
Mounting — DIN‑rail or rack installation
Protection Class — Industrial grade

FAQ

Q1: What is the maximum voltage supported by the TU891?
The TU891 supports up to 50 V per channel, depending on connected I/O modules.

Q2: Can the TU891 handle intrinsic safety (IS) modules?
Yes, it is available in both standard and IS configurations.

Q3: How is the TU891 mounted in a system?
It can be installed on DIN‑rails or within rack-mounted cabinets.

Q4: What functions does the MTU perform?
It provides field signal termination, ModuleBus distribution, and address generation.

Q5: Which industries typically use the TU891?
Process automation, power generation, oil & gas, chemical, and manufacturing industries.