ABB 3BSE037760R1 TB840A Optical ModuleBus Modem Unit

Module Feature

3BSE037760R1 (TB840A) is an optical cluster modem for ABB System 800xA S800 I/O system. It bridges electrical ModuleBus and optical ModuleBus, enables long-distance cluster interconnection of S800 I/O racks. It supports 1+1 line and module redundancy, hot swap without rack power down. Maximum 12 I/O modules per electrical bus segment, up to 7 clusters on fiber ModuleBus. Built-in bus supervision function. Widely stocked as spare for power, pulp & paper and chemical plant 800xA DCS cabinets.

Working principle

The modem receives electrical ModuleBus signal from local S800 I/O rack. Signal is converted to optical signal and transmitted over fiber to remote clusters; incoming optical signal is converted back to electrical ModuleBus signal. Redundant dual fiber paths provide communication backup, single fiber break will not interrupt I/O data exchange. Internal circuit monitors bus quality, power and fiber link status and reports fault to controller.

Onboard components

ModuleBus signal transceiver, fiber optical transceivers, redundant link switching circuit, status monitoring logic, power regulation circuit and DIN rail housing.

LED indicators

Front LEDs indicate power, run, fiber link, ModuleBus and fault status.

Hardware self‑diagnosis

Unit continuously monitors optical link health, ModuleBus communication and internal power supply. No local parameter adjustment required.

Programming software

ABB Control Builder M, used for I/O cluster configuration, redundancy setup and fault log viewing.

Electrical & Process Parameters

Model: 3BSE037760R1 Brand: ABB Device type: TB840A ModuleBus optical modem Protocol: ABB ModuleBus Function: Electrical-to-optical conversion and redundant communication for S800 I/O cluster

Mechanical & Structure

Mounting: DIN rail mounting inside control cabinet Protection class: IP30 Housing: Plastic enclosure

Environmental

Operating temperature: 0℃ ~ +55℃ Storage temperature: -40℃ ~ +70℃ Ambient humidity: 5~95% non‑condensing

Certification: CE, ATEX Zone2, DNV marine approval Status: Original ABB 800xA DCS spare

Installation

Cut off rack power before replacement. Mount modem on DIN rail, wire electrical ModuleBus terminal, connect dual fiber ports, verify redundant link and I/O communication after commissioning.

Interface

Electrical ModuleBus terminals, dual fiber optical ports, 24V DC power terminals.

Diagnostic

Link fault: Fiber cable break, dirty fiber connector or optical port damage. ModuleBus error: Short circuit or overload on electrical ModuleBus segment. Redundancy fail: Only one fiber channel available.

Product Brief

3BSE037760R1 modem, ABB TB840A redundant optical ModuleBus modem spare for 800xA S800 distributed I/O cluster communication replacement.