ABB TU847: Redundant Module Termination Unit for CI840/CI840A PROFIBUS DP-V1 Field Communication Interfaces

1. Product Overview

The ABB TU847 is a compact, passive Module Termination Unit (MTU) specially designed for the S800 I/O system in ABB 800xA and Freelance 800 control platforms. It provides the electrical and mechanical interface for redundant configuration of the CI840/CI840A PROFIBUS DP-V1 communication interfaces, supporting up to two CI840/CI840A modules while distributing power, ModuleBus signals, and station addresses (0–99).

With a rugged DIN-rail footprint and full compliance with marine, hazardous-location, and industrial standards, the TU847 is the ideal field termination solution for process automation, power generation, oil & gas, marine, and heavy industry applications. It delivers reliable, one-wire connections for PROFIBUS DP-V1 signals and process power, significantly simplifying installation while maintaining high availability through built-in redundancy.

2. Core Technical Specifications

The TU847 is engineered for marine-grade reliability and seamless integration with ABB’s S800 I/O family:

Communication & Power: Supports two redundant CI840/CI840A PROFIBUS DP-V1 interfaces (DSUB9 connectors); RJ45 service ports for tool connection; dedicated power supply terminals (19.2–30 V DC, nominal 24 V).
ModuleBus & Address Generation: Electrical ModuleBus distribution (max 5 V / 1.5 A, max 24 V / 1.5 A); two rotary switches for station address (0–99); automatic address shifting via mechanical keying.
I/O & Process Connections: Supports single (non-redundant) S800 I/O modules with one-wire field wiring; process power distribution terminals; no built-in I/O channels (passive termination unit).
Mechanical Features: Four mechanical keys (two per position = 36 configurations) to prevent wrong module insertion; latching device for DIN-rail mounting and grounding; hot-swap not supported (power must be removed for module removal).
Mounting & Dimensions: Vertical or horizontal DIN-rail; 124 mm (W) x 186 mm (H including latch) x 47 mm (D); approx. 0.5 kg.
Environmental & Safety: – Operating temperature: 0°C to +55°C (approvals +5°C to +55°C); vertical mounting max +40°C – Storage temperature: –40°C to +70°C – IP20, Pollution degree 2, ISA-S71.04 G3 corrosion protection – EMC: EN 61000-6-2 / -4 – Overvoltage category: Class I (earth protected) – Certifications: CE, UL, cULus, ATEX Zone 2, IECEx, Marine (ABS, BV, DNV-GL, LR), RoHS

All internal voltages are monitored, and the unit provides software-controlled fail-safe modes when paired with CI840/CI840A modules.

3. Key Features & Advantages

The TU847 delivers unmatched simplicity, safety, and high availability for S800 installations:

Redundant CI840/CI840A Support: Dedicated hardware and software interfaces for 1+1 redundancy, enabling automatic switchover during communication failures without interrupting the process bus.
Built-in Address & Keying Safety: Two rotary switches + mechanical keying eliminate addressing errors and prevent incorrect module insertion, protecting against miswiring and damage.
One-Wire Field Connections: Reduces wiring complexity, cabinet space, and installation time while maintaining high reliability.
ModuleBus Optical Port Ready: Connector for TB842 optical ModuleBus port via TB806, allowing easy extension to optical clusters.
Rugged Marine & Hazardous-Ready Design: Fully type-approved for offshore, marine, and hazardous (Zone 2 / Div 2) environments.
Maintenance-Friendly: Easy DIN-rail mounting, clear labeling, and compatibility with ABB’s S800 Engineering Tool for configuration and diagnostics.

These features ensure high system availability, reduced lifecycle costs, and seamless integration with ABB’s distributed PROFIBUS philosophy — the same philosophy that powers thousands of installations worldwide.

4. Applications & Real-World Value

The ABB TU847 is the field termination backbone for ABB’s S800 I/O in critical industries:

Process Automation & Oil & Gas — Direct interface for PROFIBUS DP-V1 devices in production plants, refineries, and offshore platforms.
Power Generation & Utilities — Reliable termination in turbines, boilers, and substations with redundant communication.
Marine & Offshore — ABS, DNV-GL, and LR type-approved for ships, FPSOs, and offshore installations.
Manufacturing & Heavy Industry — Compact solution for control cabinets requiring space-efficient, high-reliability PROFIBUS termination.
Safety-Critical Systems — Supports SIL-rated applications when paired with redundant CI840/CI840A and appropriate S800 modules.

By selecting the ABB TU847, system integrators and plant operators gain a proven, type-approved component that simplifies wiring, reduces cabinet footprint, and delivers the rock-solid performance expected from ABB’s S800 platform. It is the smart choice for both new installations and retrofits where reliability, redundancy, and ease of maintenance are paramount.

Need a customized product description, comparison with TU846 / TU848 / TU849, technical datasheet excerpt, or a version tailored for a specific ABB system (800xA, Freelance, etc.) or industry? Just let me know — happy to refine it further!