The TU831V1 is a high-performance Extended Module Termination Unit (MTU) designed specifically for the ABB Ability™ System 800xA and S800 I/O systems. This product serves as a passive connection unit between field signals and I/O modules, providing reliable electrical connections and hosting part of the ModuleBus communication functionality. The TU831V1 features a compact design and robust construction, making it suitable for industrial automation control systems that demand high reliability, safety, and wiring convenience.
As an 8-channel, 250V rated termination unit, the TU831V1 is compatible with digital I/O modules such as DI820, DI821, DO820, and DO821, with a maximum continuous current of 3A per channel. Its modular design offers excellent electrical isolation and mechanical protection, making it widely applicable in automation control systems across various sectors including power, process industries, manufacturing, and infrastructure.
II. Key Features and Benefits
High-Density Channel Design
The TU831V1 provides up to 8 fully isolated I/O channels, with two terminals per channel for a total of 16 connection points, supporting high-density signal access and saving installation space.
High Voltage and High Current Support
Rated voltage up to 250V and maximum continuous current of 3A per channel, suitable for most industrial field signal requirements with strong compatibility.
Reliable Mechanical and Electrical Design
Equipped with mechanical keying (2 keys, 36 combinations) to prevent incorrect I/O module insertion, enhancing system safety.
Built-in mechanical locking mechanism ensures the I/O module is fully seated before operation, preventing faults due to poor contact.
Uses screw terminals with large contact areas, supporting larger wire sizes for secure and reliable connections.
Flexible Mounting Options
Integrated ModuleBus Communication
The MTU not only connects field signals but also handles ModuleBus distribution and address transmission, enabling automatic addressing of I/O modules through position signal shifting, simplifying system configuration.
Excellent Environmental Adaptability
Complies with multiple international standards, CE marked, suitable for industrial environments with IP20 protection rating, and operates reliably within a temperature range of 0 to +55°C.
III. Product Structure and Connection Description
The TU831V1 adopts a modular structural design, primarily consisting of the following parts:
Terminal Block Area (X1)
Provides 16 screw terminals divided into 8 channels, with A and B terminals for each channel. The terminals are clearly arranged and labeled for easy field wiring. Supports larger cross-sectional area conductors for secure connections with low contact resistance.
ModuleBus Connector
Located on the side of the unit, used to connect to the upstream MTU or I/O modules, enabling ModuleBus communication and power distribution.
Mechanical Keying System
Equipped with two adjustable mechanical keys. Users can set the corresponding key positions according to the I/O module type to prevent incorrect module insertion and improve system reliability.
DIN Rail Latch
A spring latch at the bottom snaps into standard DIN rail during installation and can be easily released with a screwdriver. Provides secure mounting and good grounding.
Module Locking Mechanism
After the I/O module is inserted, it is secured by a locking lever, which simultaneously sends a "BLOCK" signal to the module, ensuring the module enters its initialization state only after being physically locked, preventing risks associated with hot swapping.
Terminal Arrangement (X1):
| Position | Row A | Row B |
| 1 | A1 | B1 |
| 2 | A2 | B2 |
| 3 | A3 | B3 |
| 4 | A4 | B4 |
| 5 | A5 | B5 |
| 6 | A6 | B6 |
| 7 | A7 | B7 |
| 8 | A8 | B8 |
IV. Application Areas
The TU831V1 is suitable for various industrial automation control systems, particularly excelling in the following scenarios:
Process Industries
Such as chemical, petroleum, pharmaceutical industries, for connecting field sensors, actuators, and other devices in process control systems.
Power Systems
In substation automation, distribution monitoring systems, for acquisition and output of digital signals.
Manufacturing Automation
Production line control, equipment monitoring, safety interlocking, etc., for reliable connection of various industrial signals.
Infrastructure
Building automation, traffic control, water treatment systems, for signal conditioning and distribution.
Marine and Offshore Engineering
With marine certification, suitable for signal connection in ship control systems.
V. Installation and Usage Guidelines
Installation Steps:
Snap the TU831V1 onto a standard DIN rail, press until the latch engages.
Adjust the mechanical keys using a screwdriver to match the type of I/O module to be installed.
Insert the I/O module into the MTU along the guide rails, ensuring accurate alignment.
Push the locking lever to secure the module to the MTU. The module then receives the "BLOCK" release signal and enters the operational state.
Connect field signal wires to the corresponding terminals according to the wiring diagram, tightening screws to the recommended torque (0.5-0.6 Nm).
Usage Notes:
Ensure the operating voltage does not exceed 250V and the current per channel does not exceed 3A.
Use wires that meet the specified requirements during wiring; avoid using wires that are too thin or too thick.
The installation environment should meet IP20 protection requirements; avoid direct exposure to water droplets or dust.
Pay attention to heat dissipation in high-temperature environments (close to 55°C), and avoid prolonged full-load operation.
VI. System Integration and Compatibility
The TU831V1 is an important component of the ABB System 800xA® hardware family and is fully compatible with the S800 I/O system. It communicates with the upstream controller via ModuleBus and supports module-level hot swapping (under system permissions), facilitating maintenance and expansion.
This MTU supports complete electrical isolation per channel, effectively preventing field interference signals from entering the control system, thereby enhancing overall system noise immunity and reliability. Furthermore, its modular design allows flexible channel configuration, enabling the selection of different quantities of I/O modules based on actual needs.
