ABB 3BSE036634R1

Technical Dossier

Product Details And Specifications

ABB TB825 Series Technical Notes

The ABB TB825 (3BSE036634R1) is an Optical Media Converter module within ABB's S800 I/O system, designed for use with the AC800M process controller platform. This series occupies a critical position in global heavy industry infrastructure, with documented installations across petrochemical refineries, nuclear power facilities, pulp and paper plants, and offshore oil and gas platforms. The S800 I/O system — of which the TB825 is a communication backbone component — is one of the most widely deployed distributed I/O architectures in process automation, with an installed base spanning more than 100 countries. The TB825 converts electrical signals to optical fiber signals on the S800 I/O bus, enabling noise-immune, long-distance communication between I/O clusters and the AC800M controller. Its role is infrastructure-level: without functional media converters, entire I/O segments become unreachable.

The Evolution of TB825 Architecture

The S800 I/O system was introduced by ABB in the mid-1990s as a modular, distributed I/O platform for the Advant OCS and later the AC800M controller family. Early generations used copper-based fieldbus connections; the TB8xx media converter family was introduced to extend the S800 optical bus, enabling fiber-optic segments up to 1 km in length. The TB820 was the first-generation optical media converter, supporting a single optical branch. Subsequent revisions — TB820V2, TB825, TB826, TB840, TB842 — progressively added redundancy support, increased branch counts, and improved hot-swap capability. The TB825 (3BSE036634R1) specifically supports dual optical branches with redundant power input, making it the standard choice for SIL-rated and high-availability process segments. As of 2024, the S800 I/O system is in a mature/sustained phase: ABB continues to supply spare parts and firmware updates, but new feature development has migrated to the S900 I/O and ABB Ability™ System 800xA platform. For plants committed to AC800M through the 2030s, maintaining a spare parts inventory of TB825 and related modules is a standard lifecycle management practice.

TB825 Full Catalog & Functionalities (SKU List)

The following SKUs represent the core S800 I/O module range. Each is a discrete, independently replaceable field unit. Functional categories: MB = Media Converter/Bus Terminator, AI = Analog Input, AO = Analog Output, DI = Digital Input, DO = Digital Output, PWR = Power Supply.

TB825 / 3BSE036634R1: Dual-branch optical media converter for S800 I/O; supports redundant optical bus topology.
TB820V2 / 3BSE013208R1: Single-branch optical media converter, second-generation; standard non-redundant bus extension.
TB840 / 3BSE037760R1: Redundant optical media converter with integrated bus termination; used in high-availability segments.
TB842 / 3BSE042554R1: Redundant optical media converter with extended diagnostics; successor to TB840 in SIL applications.
TB850 / 3BSE023676R1: S800 I/O bus terminator module; required at the end of each optical branch.
TB851 / 3BSE023675R1: S800 I/O bus terminator with integrated power distribution; used in extended I/O clusters.
TB852 / 3BSE023674R1: Redundant bus terminator for dual-branch S800 configurations.
TB810 / 3BSE008560R1: S800 I/O bus modem; copper-based fieldbus interface for short-distance I/O clusters.
TB811 / 3BSE008561R1: S800 I/O bus modem with extended addressing; supports larger I/O node counts.
TB815 / 3BSE013208R1: S800 I/O optical media converter, single branch; early-generation field unit.
TB845 / 3BSE021456R1: Redundant optical media converter; intermediate generation between TB840 and TB842.
TB848 / 3BSE048294R1: High-density optical media converter; supports up to 8 I/O modules per branch.
TB826 / 3BSE036635R1: Dual-branch optical media converter with extended fiber reach; used in large-footprint plants.
TB827 / 3BSE036636R1: Optical media converter with integrated diagnostics port; supports remote fault isolation.
TB806 / 3BSE008562R1: S800 I/O power supply module; 24 VDC input, redundant output for I/O cluster power rail.
AI810 / 3BSE008516R1: 8-channel analog input module; 4–20 mA / 0–10 V, HART-transparent.
AO810V2 / 3BSE038415R1: 8-channel analog output module; 4–20 mA, HART pass-through, second generation.
DI810 / 3BSE008508R1: 16-channel digital input module; 24 VDC, sink/source configurable.
DO810 / 3BSE008510R1: 16-channel digital output module; 24 VDC, 0.5 A per channel.
AI820 / 3BSE008544R1: 8-channel analog input module; RTD/thermocouple inputs, Pt100/Pt1000 compatible.