ABB TB825 Modules | 3BSE036634R1

Technical Dossier

Product Details And Specifications

ABB TB825 Series: Comprehensive Module Range and Technical Overview

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.

Sourcing Hard-to-Find & Obsolete TB825 Series Parts

DriveKNMS maintains a dedicated inventory of S800 I/O components, including discontinued and long-lead-time modules. The TB820 (first generation), TB810, TB811, and TB815 are no longer manufactured by ABB; lead times through official channels can exceed 26 weeks or result in no-quote responses. DriveKNMS sources these units through certified secondary market channels, performs incoming inspection against ABB technical specifications, and provides traceability documentation. For plants operating under IEC 61511 functional safety requirements, DriveKNMS can supply TB825 and TB842 units with full test records and certificate of conformance. Lifecycle extension support includes: cross-reference mapping from obsolete part numbers to current equivalents, firmware version verification, and compatibility confirmation against specific AC800M controller revisions (PM851, PM856, PM860, PM861, PM864, PM866).

Quality Control for the TB825 Range

S800 I/O media converter modules present specific test challenges due to their role as optical bus infrastructure. DriveKNMS applies the following test protocol to all TB825 and related media converter units: (1) Visual inspection of optical transceiver ports and backplane connector pins under 10× magnification. (2) Optical power output measurement at 850 nm wavelength using calibrated optical power meter; acceptance threshold per ABB specification 3BSE036634. (3) Functional bus communication test: module installed in live S800 I/O rack with AC800M controller, full I/O scan cycle verified at 10 ms and 100 ms cycle times. (4) Redundancy switchover test for dual-branch units: primary branch interrupted, switchover time measured and confirmed within ABB-specified 50 ms window. (5) 24-hour burn-in at operating temperature (0–55°C range). All test data is logged and available upon request with each unit shipment.