Intrinsic safety without power limits
The Dynamic Arc Recognition and Termination System (DART) is a dynamic power supply and control system for intrinsically safe fieldbus installations that dramatically 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 50 watts – exponentially more power than the approximately two watts 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 immediately switches off the power supply. In microseconds energy from the electrical system is reduced to a safe level, robbing a spark of the energy needed to ignite hazardous gases.
DART applied to fieldbus provides a much higher 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. Moreover, cable lengths as long as 1000 meters 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 quickly and ensure system availability. 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.