3BSC840157R1 | ABB TU891 Module Termination Unit

Overview

The ABB TU891 (Part Number: 3BSC840157R1) is a compact, single Module Termination Unit (MTU) designed for the S800 I/O platform. It functions as a non-redundant, passive interface baseplate engineered specifically to host Intrinsically Safe (IS) S800 I/O modules, providing a safe transition between hazardous field environments and the control system backbone.

Technical Specifications

• Product Type: Module Termination Unit (MTU) for Non-Redundant IS Configuration
• Model Code: TU891
• Part Number: 3BSC840157R1
• Manufacturer: ABB
• System Compatibility: S800 I/O / S800L I/O Systems
• Channel / Module Capacity: Single-slot layout for non-redundant Intrinsically Safe I/O modules
• Maximum Rated Voltage: 50 V
• Terminal Connection Type: Compression screw terminal block architecture
• Ingress Protection Rating: IP20 (IEC 60529 Compliant)
• Hazardous Location Ratings: ATEX / IECEx Zone 2 Compliant (when paired with approved IS modules)
• Conformal Coating: Yes (ISA-S71.04 Class G3 Compliant for harsh gas resistance)
• Physical Dimensions: 18.6 cm x 6.2 cm x 4.7 cm
• Product Net Weight: 0.23 kg

Installation Notes

• Snap the TU891 MTU securely onto a standard 35 mm metallic DIN rail until the structural grounding clips click into place.
• Configure the mechanical keying locks on the MTU surface to match the specific structural profile of the target S800 I/O module before mounting it.
• Terminate field sensor pairs and loop wiring into the dedicated compression terminals, ensuring correct wire stripping length to preserve the IP20 finger-safe rating.
• Maintain strict physical separation between the intrinsically safe field wiring connected to this MTU and any non-intrinsically safe wiring within the same enclosure.