Fieldbus Technology New Approach to Power Supply Increases Fieldbus Network Design Flexibility in Hazardous Areas

Editor: Dr. Jörg Kempf

The new FieldConnex DART Fieldbus system from Pepperl+Fuchs lets users take full advantage of the benefits of fieldbus technology where intrinsic safety is required for Zone 1 hazardous areas. This is achieved through a significant increase in intrinsically safe power. Reduced capital expenditure is achieved through larger networks, more devices connected, and a system that is easy to understand and to engineer.

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Intrinsic safety without limits thanks to the new FieldConnex DART Fieldbus system from Pepperl+Fuchs (Picture: Pepperl+Fuchs)
Intrinsic safety without limits thanks to the new FieldConnex DART Fieldbus system from Pepperl+Fuchs (Picture: Pepperl+Fuchs)

Early methods of creating intrinsically safe fieldbus systems included the Entity concept and FISCO (the Fieldbus Intrinsically Safe Concept). These enabled users to connect multiple devices to a single power supply on a fieldbus segment, but the low power available limited the number of devices per segment and the maximum cable run. This forced users to design complex bus topologies with many branches, making the cost of fieldbus more difficult to justify.

More recently, the High-Power Trunk Concept (HPTC) provided users with a safe installation in explosive environments, with high power supplied to the fieldbus segment while maintaining intrinsic safety at the device connection. Dart Fieldbus represents a revolutionary next step in the evolution of intrinsic safety.

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FieldConnex Dart Fieldbus components supply enough power to support as many devices as are typically supplied in non-hazardous areas. Spur connections, however, are designed to match requirements for today’s intrinsically safe field instrumentation. What makes Dart Fieldbus so unique is that it enables process automation users to fully benefit from the advantages of intrinsically safe fieldbus technology in hazardous areas, such as ensuring system availability and lowering total cost of ownership. Dart Fieldbus presents fieldbus users with a superior option in addition to existing solutions.

Dart Fieldbus is an exciting and superior option because it eliminates the power problem of intrinsic safety with a completely new approach to energy limitation. It allows considerably higher direct power. When energy is released, for example when disconnecting a plug, Dart switches off the current within microseconds, before the spark’s temperature is sufficient for ignition. Sparking is always a temporary phenomenon, so Dart returns to normal operation after a few milliseconds — ensuring highly available fieldbus performance. Instruments and control system continue to communicate because this disconnect takes place so fast.

FieldConnex Dart Fieldbus components are certified to IEC 60079–11, the main standard for intrinsic safety (Atex and IEC Ex). This allows approval in virtually every country with ease.