In 2006 R. STAHL introduced the intelligent power management for their ISbus device couplers. With this engineering, commissioning and expansions have become much more fool proof than ever before. Besides the standard spur protection that prevents feedback on the trunk under all conditions, the power management features a SoftStart and short circuit current limitation. During start-up of fieldbus segments, the SoftStart function energizes the connected fieldbus devices one after the other, resulting in a significant lower inrush current. Less energy needs to be supplied by fieldbus power supplies and no calculation of additional voltage drops or shortening of segments due to potentially high inrush currents is required any more.
In the event of multiple short circuits all short-circuited spurs are de-energized until the failure is eliminated. Even with multiple short circuits per coupler, the trunk is loaded with a maximum one short circuit current at a time. This avoids a possible shut down of segments in case of excessive overload. The power management is implemented more and more by other suppliers as well and will become a de facto standard for fieldbus installations soon. It is available in all R. STAHL isolating and non-isolating device couplers for Zone 1 and Zone 2 hazardous areas.