ABB TU837V1 3BSE013238R1 Extended Module Termination Unit

The ABB TU837V1, also cataloged as the 3BSE013238R1 Extended Module Termination Unit, operates as a dedicated hardware component for field signal termination and address distribution within ABB S800 I/O platforms. Supporting up to 8 individually isolated I/O channels rated at 250 V and 3 A per channel, the unit provides the physical wiring interface for DO820 and DO821 relay output modules. The termination base distributes ModuleBus power and data to the attached I/O module while shifting position signals to derive the correct address for the next adjacent MTU along the DIN rail.

Hardware Specifications

Backplane Bus Communication Velocity and Mechanical Keying

The TU837V1 handles ModuleBus distribution, passing high-speed backplane signals through to downstream S800 termination units without transmission decay. Positional address logic shifts internal control signals automatically as each MTU attaches to the chain, enabling deterministic I/O scanning across the backplane bus. Dual 6-position mechanical keying wheels enforce hardware-level lockout against incorrect I/O module insertion, preventing field-side cross-wiring faults before system initialization.

Frequently Asked Questions

Q: Does the mechanical keying arrangement on the TU837V1 affect module communication or addressing?

A: No. The two 6-position keying wheels provide physical slot keying only. They prevent the insertion of incompatible I/O modules into the base unit and do not alter electrical continuity or ModuleBus addressing.

Q: Can the TU837V1 be unlatched from the DIN rail while field wiring remains connected?

A: Yes. The base unit features an accessible mechanical latch that releases via a flathead screwdriver, allowing physical disengagement from standard 35 mm DIN rails without disrupting adjacent MTU physical alignment.

Q: Is the TU837V1 compatible with redundant S800 I/O module pairs?

A: No. The TU837V1 is designed strictly as a single-I/O base unit. Redundant I/O configurations require dual-channel base units such as the TU830 or TU833.

Field Installation Guidelines

1. DIN Rail Mounting: Snap the TU837V1 directly onto a standard 35 mm DIN rail (EN 50022). Ensure the spring-loaded bottom latch clicks firmly to establish a secure mechanical lock and ground earth plane contact.
2. Keying Configuration: Rotate the two mechanical keying wheels to match the specific keying code designated for the target I/O module (e.g., DO820 or DO821) prior to inserting the electronic module.
3. Field Wire Termination: Strip signal wires to 8 mm and return wires to 7 mm. Insert wire ends into the screw terminals (solid 0.2 to 6 mm squared, stranded 0.2 to 4 mm squared / 24 to 10 AWG) and tighten terminal screws to a torque between 0.5 and 0.6 Nm.
4. ModuleBus Interconnection: Align the side ModuleBus edge connectors when placing adjacent MTUs side-by-side to guarantee uninterrupted backplane power and signal propagation.
5. Module Insertion: Guide the S800 I/O module straight down into the MTU guide slots until the top retaining latches snap into place.