ABB TU865 3BSE078712R1 FCI Module Termination Unit (MTU)

Overview

The ABB TU865 (Part Number: 3BSE078712R1) is a specialized Ethernet Fieldbus Communication Interface (FCI) Module Termination Unit (MTU) explicitly engineered for the System 800xA Select I/O platform. It serves as the primary infrastructure baseplate to mount single or redundant Ethernet Adapters and FCI modules, enabling high-integrity network bridging between downstream Select I/O channel clusters and AC 800M controllers.

Technical Specifications

• Product Type: Ethernet FCI Module Termination Unit (Select I/O Architecture)
• Model Code: TU865
• Part Number: 3BSE078712R1
• Manufacturer: ABB
• Communication Protocol Support: Ethernet-based Fieldbus
• Module Slot Allocations:
  • 2 slots for Redundant CI845 FCI Communications Modules
  • 2 slots for Redundant TC810 / TC811 Ethernet Adapters
  • 1 dedicated slot for an HI880 High Integrity Module (for SIL3 safety applications)
• Downstream Routing Capacity: Interfaces with up to 12 Select I/O Modular Termination Units (MTUs)
• Mounting Layout: Vertical 35 mm DIN Rail Mounting
• Ingress Protection Rating: IP20 (IEC 60529 Compliant)
• Hazardous Location Ratings: ATEX Zone 2 (II 3G Ex nA/eC IIC T4 Gc) / Class I, Div 2, Groups A, B, C, D T4
• Operating Temperature Limits: -40°C to +70°C (-40°F to +158°F)
• Corrosive Environment Rating: Standard ISA-S71.04 Class G3 protection against harsh chemical gases
• Physical Dimensions: 21.0 cm x 13.5 cm x 9.55 cm
• Product Net Weight: 0.50 kg (including base)

Included Accessories (Factory Package)

• TL814K01 Empty Slot Cover Plate: 1 piece included standard to seal and safeguard unpopulated positions from structural dust and physical touch hazards.

Installation Notes

• Snap the TU865 MTU vertically onto standard 35 mm metallic DIN rails, ensuring locking tabs seat correctly.
• Ensure the rear ear clips anchor firmly onto paint-free areas of the grounding rail to secure continuous frame shielding.
• Only connect dedicated Select I/O sub-components to the onboard ModuleBus cluster extension ports; do not mix legacy S800 I/O modules into this terminal footprint.
• Keep the included TL814K01 shield panel locked over any unpopulated adapter slots to maintain ambient airflow and safe IP20 boundaries.