Pepperl+Fuchs' Dynamic Arc Recognition and
Termination System (DART) is a power supply and control system for intrinsically safe
fieldbus installations that increases the power available to field devices in
explosion hazardous areas, while maintaining intrinsically safe energy
levels.
During normal
operation, a DART power supply feeds full nominal power of 8 to 50W - more
power than the approximately 2W that is normally permissible in intrinsic
safety environments. Should a fault occur the potential spark remains
non-incendive, and DART detects the resulting change in current and switches
off the power supply. In msecs energy from the electrical system is reduced to
a safe level, so a spark does not ignite hazardous gases.
DART applied to
fieldbus provides an intrinsically safe power allowance to the trunk so that
the segment can support up to about 32 devices per segment - the maximum
permitted per segment. This reduces capital costs by eliminating excessive
fieldbus infrastructure. Cable lengths as long as 1000 m are possible,
opening up many application areas to fieldbus technology while maintaining
intrinsic safety requirements for all devices and cables, including the trunk
line. The higher device count per segment eliminates the problem of having to
design complex network topologies with many sub-segments, each requiring its
own power supply, junction boxes and barriers.
DART technology also offers advanced diagnostics to help users rectify problems. And because DART Fieldbus is designed as a fieldbus infrastructure for existing IS field devices and DCS systems, or for any installation in which an intrinsically safe fieldbus segment is required, it is suitable for both green- and brown field sites.
