Description

1. Product Overview

ABB TU814V1 (Part No.: 3BSE013233R1) is a compact 16-channel sourcing-type 24VDC dedicated terminal mounting base (MTU Module Terminal Unit) of the S800 I/O series, compatible with the AC 800M DCS distributed remote I/O control system. It serves as a standardized passive wiring transition base for on-site 24V DC instruments and digital equipment. It integrates two groups of electrically isolated 8-channel signal loops, with built-in loop voltage monitoring and channel status indicators. Multiple bases can be daisy-chained via the internal ModuleBus backplane bus, which automatically assigns a unique hardware address to each I/O module in the slot without manual DIP switch configuration, effectively avoiding faults such as duplicate I/O addresses and configuration matching errors on site.

This terminal unit has a maximum rated withstand voltage of 50VDC and a rated load current of 2A per channel, with a maximum current of 5A for the common process loop. It adopts crimp snap-in terminals and is equipped with mechanically coded anti-misplug lock strips to physically prevent short-circuit burnout caused by incorrect insertion of different types of I/O modules. Designed for bidirectional mounting on standard 35mm DIN rails, it features Industrial Class A EMC performance and wide-temperature adaptability. It is widely used in 24V DC measuring point signal collection scenarios in process industries including power, chemical, metallurgy, oil & gas and water treatment, commonly applied to wiring of new sourcing-type DI input points, spare replacement of legacy compact S800 terminal bases, and I/O measuring point expansion renovation of DCS control systems.

2. Hardware Structure and Composition

2.1 16-Channel Group-isolated Field Signal Wiring Unit

It integrates 16 process signal terminals divided into two electrically independent isolated loops with 8 channels each, supporting real-time loop voltage monitoring and independent LED status indicators for each channel to visually display on-site signal connectivity. It is specially designed for sourcing-type 24VDC digital input modules, connecting field devices such as valve position feedbacks, proximity switches, relay contacts and 2-wire transmitters. Two sets of independent common power terminals are reserved to supply power separately for the two groups of loops and suppress inter-group signal crosstalk. The crimp-type terminals accept solid wires (0.2~4.0mm²) and stranded wires (0.2~2.5mm²), featuring vibration resistance and anti-loosening performance to eliminate poor contact and signal disconnection faults caused by long-term plant vibration.

2.2 ModuleBus Backplane Bus Daisy-chaining & Automatic Hardware Addressing Unit

A passive high-speed ModuleBus backplane transmission loop is embedded to support end-to-end daisy-chain expansion of multiple TU814V1 units. It receives bus signals from the previous terminal base and transmits data to the next one, allowing multiple groups of I/O measuring points to be connected to a single bus link. Hardware addresses are automatically allocated via backplane displacement encoding signals without manual DIP switch or software configuration, enabling the controller to accurately identify each of the 16 channels, greatly shortening the commissioning cycle of remote I/O stations and avoiding human errors such as address conflicts and misassigned measuring points.

2.3 Mechanically Coded Anti-misplug Safety Positioning Unit

Two groups of adjustable mechanical coding lock strips with 6 gears each provide 36 hardware positioning combinations. Exclusive physical lock positions are configured for various compact AI, AO, DI, DO I/O modules; only modules with matching codes can be inserted into corresponding slots, preventing pin short-circuit and chip breakdown caused by mixed use of high/low voltage or analog/digital modules. It is especially suitable for high-density control cabinets with various I/O devices, reducing the risk of man-made hardware damage during installation and maintenance.

2.4 DIN Rail Mounting & Shielded Earthing Protection Unit

The base adopts a snap-on DIN rail locking structure supporting both horizontal and vertical cabinet installation. Integrated dedicated earthing contacts realize full-unit shield earthing when mounted on a grounded DIN rail to suppress common-mode electromagnetic interference. Made of flame-retardant high-temperature resistant engineering plastic with physically separated strong and weak current wiring areas, it is fully backward compatible with legacy MTU bases of the same series, enabling direct on-site replacement without large-scale modification to existing cables and rail layout, and supporting hot swapping of matched I/O modules for convenient maintenance.

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3. Technical Specifications

3.1 Electrical Specifications

Rated Withstand Voltage: Max. 50VDC; dielectric withstand test: 500VAC
Rated Current per Channel: 2A; maximum allowable current for common process loops: 5A
Channel Grouping: 2 electrically isolated loops (8 channels per group), supporting loop voltage monitoring + single-channel status LED indicators
Compatible Cable Specifications: Solid wire 0.2~4.0mm², stranded wire 0.2~2.5mm²
Wiring Method: 3-row crimp snap-in terminals
Bus Type: Passive ModuleBus backplane daisy-chain bus, no external power supply required
Compatible Modules: Full range of S800 compact I/O modules including AI810, AI815, AO810, DI810, DI811, DI814, DI830
Number of Channels: 16 sourcing-type 24VDC isolated process signal channels

3.2 Environmental Specifications

Operating Temperature (Horizontal Mounting): 0℃ ~ +55℃; Operating Temperature (Vertical Mounting): 0℃ ~ +40℃
Storage & Transportation Temperature: -40℃ ~ +70℃
Relative Humidity: 5%~95% RH, non-condensing, free of corrosive gas and conductive dust
EMC Compliance: IEC 61000 Industrial Class A anti-interference standard
Protection Class: IP20, only for installation in indoor ventilated and enclosed industrial control cabinets

3.3 Mechanical Specifications

Mounting Method: Bidirectional snap-on mounting on standard 35mm DIN rails
Net Weight: Approx. 0.18kg
Enclosure Material: Flame-retardant high-temperature resistant engineering plastic
Optional Accessories: S800 series compact I/O modules, shielded signal cables, DIN earthing rails, terminal marking tags

4. Product Functions and Features

Dual 8-channel electrical isolation design with voltage monitoring and channel status indication

The 16 channels are divided into two mutually isolated independent loops that can be powered separately to eliminate electrical interference between measuring point groups. Real-time loop voltage monitoring and single-channel LED indicators enable maintenance personnel to quickly locate faults such as open circuits, short circuits and signal loss, ideal for centralized collection of massive 24V digital signals.

Passive bus daisy-chaining + automatic hardware addressing for rapid large-scale I/O networking

No external power supply is required. Multiple terminal bases can be expanded via backplane ModuleBus daisy-chaining with automatic I/O address assignment, eliminating manual DIP switch configuration to reduce configuration errors and realize rapid distributed remote I/O deployment for hundreds of measuring points in large-scale plants.

Mechanically coded anti-misplug design provides comprehensive hardware protection for I/O cards

Physical locking restricts installation to matched I/O modules only, fundamentally preventing power short-circuit and chip burnout caused by misinstallation of analog and digital modules, greatly improving operational safety during installation and maintenance in high-density I/O cabinets.

Wide-temperature bidirectional industrial design ensures long-term stable operation in harsh working conditions

The flame-retardant sealed enclosure with shield earthing delivers excellent dustproof, moisture-proof and anti-electromagnetic interference performance, adapting to high-dust and strong-interference plants such as metallurgical, thermal power and chemical facilities. Hot swapping of matched I/O modules is supported to avoid production shutdown during maintenance.

Standardized modular design facilitates spare part replacement and system capacity expansion

Fully backward compatible with all S800 compact I/O modules, legacy terminal bases can be directly replaced on site without modifying existing wiring. The standard DIN rail structure reduces construction and commissioning costs for DCS renovation and measuring point expansion projects.

5. Applicable Working Conditions and Application Scenarios

Wiring of 24V sourcing-type DI measuring points for AC800M DCS remote I/O stations in petroleum refining and coal chemical plants, for centralized signal collection of valve feedbacks, field switches and 2-wire instruments.
Digital input measuring point wiring for auxiliary control systems such as boilers, desulfurization, denitrification and water treatment in thermal power and waste incineration power plants, as well as DC instrument signal conversion projects for local control cabinets.
Signal collection and wiring for 24V field devices such as limit switches, relays and motor auxiliary feedbacks in sequential interlock control systems of papermaking, metallurgical and cement production lines.
New construction and capacity expansion renovation of automatic control systems for municipal water and sewage treatment plants, suitable for intensive wiring of multi-loop 24V DC instruments.
Spare part replacement for aging faulty compact S800 terminal bases and upgrading projects for 24V digital measuring point expansion.

ABB TU814V1 3BSE013233R1 MTU Module (Terminal Unit)