MTL Redundant Fieldbus Barriers

The MTL redundant Fieldbus barriers are field-mounted wiring hubs that create up to six intrinsically safe spur connections from a high-energy trunk, for connection to suitably certified Foundation fieldbus H1 instruments. They may be installed in Zone 1 (gas) or Zone 21 (dust) hazardous areas, with the trunk wiring implemented using suitably protected cable and increased safety (Ex e) connection facilities.

Each enclosure system uses duplicated Fieldbus barrier modules in a redundant configuration to achieve significantly higher system availability than equivalent ‘simplex' units. The 9372-FB may therefore be selected for critical process applications where failure of the Fieldbus barrier would otherwise result in unacceptable downtime or lost production. It is also ideal for use in Fieldbus Safety Instrumented Function (SIF) networks in which nuisance trips cannot be tolerated. Failure notification to the host control system is provided by means of an integrated Foundation fieldbus device with Digital Input Function Block capability.

In common with conventional Fieldbus barriers, each intrinsically safe spur can support a FISCO or ‘Entity' certified fieldbus device located in a Zone 0 or 1 hazardous area. The short-circuit protected spurs are galvanically isolated from the trunk and require no protective ground connection in the field.

The 9372-FB redundant fieldbus barrier is based on MTL's 9370-FB range of products, which are supplied as complete, factory-assembled enclosure systems that do not require additional wiring, customized housings or complex ancillary components. Electrical and mechanical aspects of the design are integrated, providing a complete, ergonomic solution for ‘High Energy Trunk' applications in hazardous areas.

The key modular components of the system (Fieldbus barrier, terminator and surge protectors) may be ‘hot-plugged' by design and without gas clearance procedures or separate isolating switches. This virtually eliminates the risk associated with hazardous area maintenance activities, speeds module replacement and avoids the need for specialist operator training.

The 9372-FB Fieldbus barriers are bus powered and requires no additional power supply in the field. When used with a fieldbus host control system, power for the trunk may be provided by redundant power supplies.