Description

ABB TU850 S800 I/O Termination Unit

Configured for field-signal termination and I/O signal distribution in the ABB S800 I/O system, the ABB TU850 3BSE021445R1 (TU850 Termination Unit) provides the physical connection between field wiring and compatible I/O modules. It supports signal termination, field-side power distribution, and DIN-rail installation.

Hardware Specifications

Parameter	Specification
Model	TU850
Product ID	3BSE021445R1
Brand	ABB
Product Type	Termination Unit
System Compatibility	ABB S800 I/O System
Module Bus Connection	Optical ModuleBus / Cluster Modem, depending on configuration
Number of Channels	Supports multi-channel I/O modules; typically 16 channels
Voltage Rating	24 VDC; maximum 50 VDC / 30 VAC
Current Rating	Maximum 2 A per channel; subject to the connected I/O module limits
Mounting	DIN rail, EN 60715, 35 mm
Connection Type	Screw terminals or spring terminals, depending on sub-version
Degree of Protection	IP20, IEC 60529
Operating Temp	0 deg C to +55 deg C
Storage Temp	-40 deg C to +70 deg C
Relative Humidity	5% to 95%, non-condensing
Dimensions	Approx. 61 mm x 125 mm x 64 mm
Weight	Approx. 0.2 kg

ABB I/O Density and Interface Architecture

The TU850 provides the physical termination interface for S800 I/O modules and organizes field connections at the module termination point. It supports multi-channel I/O configurations and reduces individual field-wire routing to the I/O assembly. The module bus connection can use Optical ModuleBus or a Cluster Modem arrangement according to the system configuration.

The TU850 itself is a termination unit rather than a PLC CPU, communication processor, or Ethernet interface. Therefore, specific Profinet, EtherNet/IP, firmware, or network-cycle performance data should not be assigned to this component without a corresponding ABB specification.

Frequently Asked Questions (FAQ)

Q: What is the primary electrical function of the TU850?

A: The TU850 terminates field wiring and provides the physical signal interface and distribution path between field circuits and compatible ABB S800 I/O modules.

Q: Can the TU850 be installed directly on a DIN rail?

A: Yes. The supplied specification identifies 35 mm EN 60715 DIN-rail mounting.

Q: Does the TU850 have a specified power-consumption value?

A: No. The supplied technical data does not specify a separate TU850 power-consumption figure. The connected I/O module and system configuration determine the applicable electrical loading.

Field Installation Guidelines

• Install the TU850 on a compatible 35 mm EN 60715 DIN rail and secure the unit against mechanical movement.
• Verify the exact TU850 sub-version before selecting screw or spring terminal wiring.
• Confirm the connected I/O module's voltage and current limits before applying field power.
• Keep signal wiring separated from high-voltage power and high-current switching conductors to reduce electromagnetic coupling.
• Route shielded signal cables according to the cabinet grounding design and terminate cable shields using the plant's defined EMC grounding method.
• Verify field polarity and terminal identification against the applicable ABB system documentation before energizing the circuit.
• Maintain adequate clearance for terminal access, module removal, and inspection.
• Do not assign network, firmware, or hot-swap characteristics to the TU850 unless the applicable S800 I/O system documentation explicitly defines them.
• Check the installed assembly for loose terminals, damaged conductors, and incorrect field connections before commissioning.

Specifications

• Brand: ABB

Advantages

• High reliability in industrial environments
• Supports continuous operation
• Compatible with major PLC/DCS systems