3BSE068782R1 | ABB TU851 Extended Module Termination Unit (MTU)

Description

The TU851 is a 16-channel, 250V Extended Module Termination Unit (MTU) designed for the ABB S800 I/O system. This MTU is a passive unit that serves as the interface for connecting field wiring to the I/O modules, and it also integrates part of the ModuleBus.

The TU851 supports up to 16 I/O channels, with a maximum rated voltage of 250V and a rated current of 3A per channel. The MTU functions by distributing the ModuleBus signals to the I/O modules and to subsequent MTUs. It also manages address generation by shifting outgoing position signals to ensure proper I/O module configuration.

Mounting is supported on a standard DIN rail, and the unit includes a mechanical latch for securing it in place. The latch can be easily released using a screwdriver for easy module replacement. The MTU features mechanical keying, allowing for up to 36 different configurations to prevent the wrong I/O module from being inserted.

The MTU also includes a mechanical locking mechanism that secures the module in position and ensures that the I/O module remains in its initialization state until it is fully locked into place.

Features

250 Volt Applications: Compatible with DO820, DI821, DI825, DI828, DO820, DO821, and DO828 I/O modules.
Up to 16 Isolated Channels: Provides up to 16 isolated channels for field signals.
ModuleBus Connectivity: Ensures connectivity between I/O modules and other MTUs in the system.
Mechanical Keying: Prevents incorrect insertion of I/O modules with 36 mechanical configuration options.
DIN Rail Mounting: Simple and secure mounting on standard DIN rails.
Mechanical Locking Mechanism: Locks I/O modules in place, ensuring they remain in their initialization state until securely positioned.

Technical Data

Item	Value
Process Connections	32 (up to 16 I/O channels, 2 terminals per channel)
Maximum Current per I/O Channel	3 A
ModuleBus Current Distribution (5V)	1.5 A
ModuleBus Current Distribution (24V)	1.5 A
Wire Sizes (Signal Connections)	Solid: 0.2 – 4mm², Stranded: 0.2 – 4mm² (24 – 10 AWG)
Mechanical Keys	36 different configurations
I/O Module Lock	Yes, locks module and enables operation
Protection Rating	IP20 (IEC 60529)
Rated Insulation Voltage	250 V
Dielectric Test Voltage	2000 V a.c.
Width	126 mm (5”) including connector, 120.5 mm (4.74”) edge to edge installed
Depth	64 mm (2.52”) including terminals
Height	110 mm (4.3”)
Weight	0.22 kg (0.48 lbs)

General Info

Article Number: 3BSE068782R1
Type: Extended
Connection: Terminal block
Voltage: 250 V
Channels: 16 I/O channels
Single/Redundant I/O: Single
Use with I/O: Compatible with DI820, DI821, DI825, DI828, DO820, DO821, and DO828 I/O modules

Detailed Data

Maximum Current per I/O Channel: 3 A
Dielectric Test Voltage: 2000 V a.c.
Wire Sizes:
- Signal Connections: Solid: 0.2 – 4mm², Stranded: 0.2 – 4mm² (24 – 10 AWG)
- Return Connections: Solid: 0.2 – 4mm², Stranded: 0.2 – 4mm² (24 – 10 AWG)
Recommended Torque: 0.5 – 0.6 Nm
Stripping Length: 8 mm for signal connections, 7 mm for return connections

Environment and Certification

CE Mark: Yes
Electrical Safety: EN 61010-1, UL 61010-1, EN 61010-2-201, UL 61010-2-201
Marine Certification: ABS, BV, DNV-GL, LR
Operating Temperature: 0 to +55°C (+32 to +131°F), approvals issued for +5 to +55°C
Storage Temperature: -40 to +70°C (-40 to +158°F)
Pollution Degree: Degree 2 (IEC 60664-1)
Corrosion Protection: ISA-S71.04: G3
Relative Humidity: 5 to 95%, non-condensing
Protection Class: IP20 (IEC 60529)
EMC Compliance: EN 61000-6-4, EN 61000-6-2
Overvoltage Categories: IEC/EN 60664-1, EN 50178
Equipment Class: Class I (earth protected)
RoHS Compliance: EN 50581:2012
WEEE Compliance: DIRECTIVE/2012/19/EU

Dimensions

Width: 126 mm (5”) including connector, 120.5 mm (4.74”) edge to edge installed
Depth: 64 mm (2.52”) including terminals
Height: 110 mm (4.3”)
Weight: 0.22 kg (0.48 lbs)

Mounting and Installation

DIN Rail Mounting: Compatible with standard DIN rails (both horizontal and vertical installations are supported).
Mechanical Locking: Includes a mechanical latch for secure mounting, ensuring proper grounding and stability.

Summary

The TU851 is a robust and versatile Extended Module Termination Unit offering 16 isolated I/O channels for S800 I/O systems. It supports a wide range of I/O modules, such as DI820, DI821, DI825, DI828, DO820, DO821, and DO828. With features like mechanical keying, fused load power terminals, and easy DIN rail mounting, it is ideal for industrial automation systems where high-voltage connections and signal isolation are critical. The MTU ensures reliable and safe communication between field wiring and I/O modules while maintaining strong mechanical and electrical safety standards.

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