ABB TB840 3BSE021456R1 ModulebuS Cluster Modem

Product Description

The TB840 (3BSE021456R1) is a high-reliability optical cluster modem engineered for the ABB S800 I/O system. Its primary function is to extend the Modulebus via optical fiber, allowing for the connection of remote I/O clusters to a central controller with complete electrical isolation. Designed specifically for mission-critical industrial environments, the TB840 supports a 1+1 redundant configuration, ensuring that a single fiber or modem failure does not interrupt the data flow between the distributed I/O stations and the parent PLC or DCS.

Technical Specifications

• Manufacturer: ABB

• Model Number: TB840

• Ordering Code: 3BSE021456R1

• Redundancy Support: 1+1 Optical Line Redundancy

• Interface Type: Optical Modulebus Cluster Interface

• Communication Media: Fiber Optic (Optical link to TB820/TB840 clusters)

• Replacement Note: Replaced by TB840A (Pin compatible; same functionality with hardware optimizations)

• Exchange Part Number: EXC3BSE021456R1

• Net Weight: 0.272 kg

• Module Width: 8 cm

• Module Height: 15.7 cm

• Module Depth: 16 cm

• Operational Status: Hardware-independent signal processing for high-speed I/O data

Operational Applications

The TB840 is essential for the following deployment scenarios:

• Decentralized I/O Architecture: Connecting S800 I/O clusters located in different electrical rooms or across large facility footprints.

• Redundant Data Links: Creating fault-tolerant communication paths in power plants and chemical processing facilities where downtime is not an option.

• EMI Mitigation: Using fiber optics to bridge areas with high electromagnetic interference where copper cabling would suffer from signal degradation.