Pepperl+Fuchs is developing two versions of the technology, DART High-Power to enable the use of higher power devices in hazardous areas without additional protection and without the need for special and costly safety precautions, and DART for Fieldbus to increase the number of devices which can be connected in IS Profibus PA or Foundation fieldbus H1 systems.
Typical of the devices that could now be contemplated in hazardous areas are industrial PCs and HMIs, LED lighting systems, higher power sensors, analyzers, solenoid valves and heating systems. In fieldbus systems, power is supplied at 24V, the maximum for Entity configurations, supporting up to 24 field devices with a total power rating of 8W per segment, provided the total cable length does not exceed 1,000 meters.
One potential snag with the DART approach appears to be that, because the length of the cable and the corresponding signal delay can have a significant influence on the response time for recognizing a potential spark, and because the characteristic of the device itself can influence how the signals are interpreted, a complete system requires a decoupling module which has to be integrated into the device itself. Consequently, Pepperl+Fuchs is looking for suitable partners to develop new products and applications. We are interested in a constructive dialog with product managers from all over the world, said Michael Kessler, director of the companys Components and Technologies business unit, who believes that the technology opens up a range applications which were previously either not feasible or required complex and costly installation techniques.
As well as lifting restrictions imposed on fieldbus systems by limited power supply, Kessler believes DART opens the way to numerous additional applications for the process industry, such as valve control, scales or emergency lighting.