Serviceline
Serviceline Industrial Sensors
Support en ligne pour la protection contre le risque d’explosion

Fieldbus in the Safe or Any Hazardous Area

Fieldbus systems are being used in ever greater numbers in the area of process automation for the following reasons:

  • Hardware - in the form of wiring, cable channels, terminals, input and output cards in the control or process control system - can be saved
  • The communication interface returns additional process values like diagnostic data. No additional interface for assigning parameters is needed, because the "intelligent" field devices can be configured and have parmeters assigned to them via fieldbus systems
  • System availability can be increased as the additional diagnostic data can be used for preventive maintenance, thus reducing system downtimes

The most popular configuration connecting field instrumentation to the DCS with fieldbus today is the trunk-and-spur topology. A main line (the trunk) carries energy and data into the field. The energy and data is distributed with one device each connected to a branch line (the spur)

The fieldbus couplers are mounted in the field near the field device. Spur lines can be up to 120 m in length. Multiple fieldbus couplers are often combined in one preconfigured housing certified for installation in the Ex-Zone.

The fieldbus distribution is selectable for the configuration and protection concept of your choice.


High-Power Trunk for long distances and high device count

Pepperl+Fuchs designed the High-Power Trunk Concept to overcome power limitations for explosion protection. We were the first to bring energy-limiting fieldbus couplers to process automation.

In principle, the trunk line transmits power of up to 31 V and 500 mA, not limited for explosion protection purposes. The fieldbus coupler - either a FieldBarrier or Segment Protector - is installed near the field instrumentation. Thus, the maximum cable length can be reached, and many devices can be connected, while simplifying verification of explosion protection. Installation and maintenance crews enjoy the benefits as field devices can be installed or maintained while the plant is in operation - all of this occurs without a hot work permit.

For Ex ic, the FieldConnex High-density Power Hubs (MBHD-FB*) and R2 Segment Protectors (R2-SP-N*) enable an economic and easy way of Ex ic explosion protection with a choice of voltages. The Power Hub limits the voltage in selected power supply modules, and the R2 Segment Protector limits the current. Both conform to the design specifications and carry certificates. Users have the choice to validate the explosion protection according to FISCO Ex ic or Entity Ex ic.


High-Power Trunk topology for the general purpose area and Zone 2/ Div. 2


High-Power Trunk in the hazardous area Zone 2/ Div. 2 implements Entity or FISCO Ex ic/ Ex nL explosion protection in a way that is economic and easy to apply. Voltage limitation is done by the power supply, current limitation by the R2 Segment Protector

High-Power Trunk Topology for Zone 1,0/ Div. 1


The FieldBarrier is the main component for the High-Power Trunk concept in Zone 1. Outputs are intrinsically safe with galvanic isolation. Field instruments can be located in Zone 0/ Div. 1.

The High-Power Trunk for flameproof (Ex d) field instrmentation in the hazardous area Zone 1/Div. 2. Short circuit protection naturally included.


This solution provides a fieldbus connection for flameproof devices. Protected installation is required for the trunk and respective spurs. Segment Protector R-SP-E12 is certified for installation in Zone 1/Div. 2. Short circuit protection at each spur