Hot Swap of Fieldbus Barriers in Explosive Atmospheres
02 October 2008
The R. STAHL miniCLIX Ex plug connector system now features new Y adapters that enable users to quickly and comfortably route two cables to one plug or socket with hot swap functionality in zone one areas.
The concept of fieldbus barriers, also known as the power trunk or high energy trunk concept, has proven to be the most powerful solution for fieldbus installations in explosive atmospheres. In this setup, a non-intrinsically safe trunk provides enough energy to power a maximum of 16 intrinsically safe / FISCO field devices per segment. Zone one fieldbus barriers, such as R. STAHL’s type 9411 field device couplers, can connect up to eight I.S. field devices per barrier to the power trunk.
However, since the trunk connection is not intrinsically safe, but is Ex-e (increased safety) or non-incendive protected, no hot swapping in zone one is permitted if a barriers fails and must be replaced. Therefore, users may have to shut down the whole segment, which would result in high standstill cost.
Type 8592 miniCLIX Y adapters are certified for hot swap of non-intrinsically safe signal lines, for example, the trunk cable of a fieldbus barrier installation. Using miniCLIX connectors and Y adapters at the trunk connection of a fieldbus barrier, each barrier can safely and easily be unplugged during operation in explosive atmospheres, without interrupting the whole segment. No special hot work permit is needed for this. Hence, this solution combines the effectiveness of the power trunk principle with the hot swap convenience of intrinsic safety. MiniCLIX connectors also allow for converting Ex-d field devices into “plug and play” versions, making all fieldbus devices hot swappable.
