ABB TU811 Compact Module Terminal Unit



ABB TU811 Compact Module Terminal Unit

Module Overview

The ABB TU811 compact module terminal unit is a key interface device in the ABB AC800M control system and expansion architecture, positioned as a "bridge between controllers and field devices", designed specifically for centralized signal processing, module management, and system expansion in industrial automation scenarios. Its core value lies in achieving centralized control of decentralized I/O modules, signal isolation conversion, and efficient data exchange with the main controller through standardized interfaces and modular structures, solving problems such as incompatible interfaces, signal interference, and complex wiring in control system expansion. At the same time, it adapts to the installation requirements of space limited control cabinets with a compact size.

As a native supporting device of the AC800M system, this terminal unit has complete system compatibility and can be directly connected to the Control Builder M configuration environment. It supports hot plugging and online maintenance and is widely used in medium and large-scale automation control systems in industries such as power, chemical, and metallurgy. It provides hardware support for reliable transmission of on-site signals and flexible expansion of the system.

Core functions and advantages

2.1 Centralized module management and expansion

The TU811 terminal unit is based on a modular architecture, which enables unified management and system expansion of various I/O modules, and solves the compatibility problem of multi type module access

-Multi module compatible access: Supports direct mounting of ABB AC800M series digital and analog I/O modules such as AI801, AO801, DI801, DO801, as well as specialized modules for temperature measurement and pulse counting. A single unit can expand up to 8 I/O modules to meet the needs of small and medium-sized signal acquisition and control.

-Unified bus management: Communication between each module and the main controller is achieved through an internal high-speed backplane bus (with a transmission rate of 100Mbps). The bus uses differential signal transmission technology to effectively reduce signal interference between modules, ensuring real-time and stable data transmission. The data exchange delay between modules is ≤ 1ms.

-Hot swappable support: Both the terminal unit and the mounted I/O module support hot swappable, which can complete module replacement and maintenance without shutting down the system, avoiding production interruptions caused by equipment maintenance and improving system availability.

2.2 Signal isolation and anti-interference processing

In response to the complex electromagnetic environment of industrial sites, TU811 has strengthened isolation and anti-interference design in the signal transmission link to ensure the accuracy of signal acquisition:

-Comprehensive electrical isolation: It has triple protection of power isolation, signal isolation, and bus isolation, with an isolation voltage of up to 2500V AC, which can effectively block common mode interference and differential mode interference between field devices and controllers, avoiding signal distortion caused by grounding loops or voltage fluctuations.

-Signal conditioning function: Built in signal filtering circuit can perform low-pass filtering on analog signals to suppress high-frequency electromagnetic interference (such as harmonic interference generated by frequency converters); Perform anti shake processing on digital signals to avoid false triggering of switch signals.

-Surge protection design: The input and output ports are integrated with surge suppression components, which can withstand transient overvoltage surges of ± 2kV, adapt to surge interference caused by industrial lightning strikes, switch operations, etc., and protect the internal circuits of the module from damage.

2.3 Efficient System Communication and Diagnosis

As a communication hub between the controller and I/O module, TU811 has efficient communication capabilities and comprehensive diagnostic functions, simplifying system operation and maintenance

-Dual port redundant communication: Comes with 2 RJ45 Ethernet ports as standard, supporting industrial Ethernet protocols such as PROFINET and EtherNet/IP, and can be configured for redundant communication mode. When the main communication link fails, it automatically switches to the backup link, with a communication switching time of ≤ 10ms, ensuring communication continuity.

-Integrated diagnostic function: Real time monitoring of the operating status of terminal units and various mounted modules through configuration software, including power supply voltage, module temperature, communication status, etc; When module failure, signal overtravel and other abnormalities occur, an alarm can be immediately triggered and the fault information recorded, making it easier for operation and maintenance personnel to quickly locate the problem.

-System clock synchronization: Supports synchronization with the system clock server through the SNTP protocol, ensuring that the event records and fault information of each module have a unified timestamp, providing accurate time basis for fault tracing and system analysis.

2.4 Compact design and convenient installation

TU811 is designed with "compactness" as its core, suitable for industrial control cabinet installation scenarios with limited space, while simplifying installation and wiring processes:

-Compact size design: It adopts a 19 inch rack mounted installation, with a height of only 3U (132.5mm), a width of 482.6mm, and a depth of 150mm. Compared with traditional terminal units, it reduces the volume by 30% and can effectively save installation space inside the control cabinet, especially suitable for small and medium-sized control systems.

-Standardized wiring terminals: Spring or screw type wiring terminals are used, supporting 2.5mm ² -4mm ² wire connections, with secure wiring and easy operation; The terminal layout is clear, distinguishing between power, signal, and communication terminals to reduce the risk of wiring errors.

-Intuitive status indication: Equipped with power indicator lights, communication indicator lights, and module status indicator lights, the equipment's operating status is displayed intuitively through different colors (red, green, yellow) and flashing modes. On site personnel can quickly determine the equipment's operating conditions without the need for software.

Key technical parameters

Power parameters

input voltage

24V DC（19.2V DC - 28.8V DC）， Support dual power redundant input

Maximum Power Consumption

No load ≤ 5W, fully equipped with 8 I/O modules ≤ 25W

Module Expansion

Expansion capability

Supports up to 8 AC800M series I/O modules

Core Bus 

High speed parallel bus, transmission rate 100Mbps, latency ≤ 1ms

communication interface

interface type

2 RJ45 Ethernet ports, 1 RS485 backup interface

Supported Protocols

PROFINET、EtherNet/IP、Modbus TCP、IEC 61131-3

Communication redundancy

Supports ring redundancy or dual link redundancy, with a switching time of ≤ 10ms

Isolation performance

isolation voltage

Isolation between power/signal/bus, isolation voltage 2500V AC (1min)

surge protection

Input/output port ± 2kV transient overvoltage protection (IEC 61000-4-5)

environmental parameters

Operating Temperature

-20 ℃ -60 ℃ (no condensation)

Storage temperature

-40 ℃ -85 ℃, relative humidity 5% -95% (no condensation)

physical properties

Installation method

19 inch 3U rack mounted installation, protection level IP20

Overall dimensions

482.6mm (width) × 132.5mm (height) × 150mm (depth)

Applicable scenarios

The TU811 compact module terminal unit, with its modular expansion, signal anti-interference, compact installation and other characteristics, has become an ideal choice for the expansion of AC800M control systems and the construction of small and medium-sized automation systems. Typical application scenarios include:

1. Power system auxiliary control: In the desulfurization and denitrification system of thermal power plants and the gate control system of hydropower stations, as a centralized management unit of on-site I/O modules, it connects temperature, pressure, liquid level and other sensor signals and valve control signals, interacts with the main controller through redundant communication, and ensures the stable operation of the auxiliary control system.

2. Chemical process control: In small and medium-sized chemical plants, it is used for local signal processing of equipment such as reaction vessels and distillation towers. The dispersed I/O signals on site are centralized and transmitted to the AC800M controller. Its signal isolation function can effectively resist strong electromagnetic interference in the chemical workshop, ensuring accurate collection of process parameters.

3. Metallurgical production line: In the regional control stations of steel rolling, continuous casting and other production lines, digital I/O modules are mounted to collect equipment operating status and control actuator actions. The compact size can adapt to small control cabinets next to the production line, and the hot plug function is convenient for quick on-site maintenance.

4. Municipal water supply project: In the pump station control system of the water plant, the current, pressure signals, and start stop control signals of each pump are centrally managed. Through Ethernet communication with the SCADA system, remote monitoring and automatic control of pump operation are achieved, simplifying the wiring and structure of the pump station control cabinet.

5. Equipment integration control: In the local control unit of large industrial equipment (such as cement rotary kilns and paper machines), as the I/O expansion core, it connects various monitoring and control signals of the equipment, works together with the equipment main controller, and improves the response speed and reliability of equipment control.