Remote I/O Supplements Fieldbus Technology in Hazardous Areas

Pepperl+Fuchs has been actively furthering bus technology for many years. The chemical, petrochemical and pharmaceutical industries employ these cost saving intrinsically safe interfaces for control and instrumentation.

In order to underline its ambition to maintain and extend its leading position in the market of fieldbus technology Pepperl+Fuchs acquired the Intrinsic Safety Instrumentation (ISB) business located in Buehl, Germany from Cooper Crouse-Hinds, a division of Cooper Industries in July 2006.

The products manufactured at the new location include one of the front runners of Remote I/O. While Foundation Fieldbus and Profibus PA address field devices which feature digital data transmission instead of conventional 20 mA signals, Remote I/O can cope with all kinds of analogue and digital inputs and outputs for process automation.

HART communication facilitates asset management

Remote I/O are particularly useful for plant retrofits and modernization where existing field instrumentation is to be kept intact to save costs. Remote I/O also opens the door to asset management making use of HART communication on the bus. The full potential of the installed base of HART transmitters can now be accessed by the plant operator in a much more efficient way than in the past. Unlike conventional handheld communicators which had to be connected manually to each loop Remote I/O addresses field devices in a similar way to a HART multiplexer. Remote I/O offers all this without any extra wiring and without extra hardware. Some DCS systems even offer HART on Profibus as an integral part of their own engineering software.

Profibus Class 2 Master for all kinds of DCS Systems

Where the favoured DCS does not offer HART on Profibus itself a class 2 master can be added to the same bus in the form of a laptop or PC. This is totally independent from the DCS and will not interfere with the operation of the DCS in any form. It opens the route to the full HART command structure allowing the user to configure field devices via the bus and even make use of asset management functions which many HART communication software packages now offer.

Pepperl+Fuchs LB/FB Remote I/O acts as the HART modem by receiving HART telegrams from a workstation or Profibus master via Profibus and modulating the 20 mA current loops of the connected transmitter supply units and output isolators. In return the field device's response will be sent back to the DCS system or a secondary master via Profibus using nested communications.

Reduced wiring costs due to installation in hazardous areas

The Remote I/O stations can be placed in Zone 1 hazardous areas so that the field wiring is reduced considerably. A combination with other non HART signals in the same Remote I/O substation is also possible.