R. Stahl is introducing its compact terminating resistor type 9418 for explosion-protected FF H1 installations. Two build types suitable for use in zone 1 and zone 21 are available: an Ex i terminator for intrinsically safe/Fisco fieldbus installations, and an Ex m model for power trunks that are not intrinsically safe. Designed to fit in M20 cable glands, 9418 terminators can be very easily attached to cable entries of e.g. field distribution panels or field devices. Fieldbus standards call for the presence of a defined terminating resistor on both ends of a bus trunk as a measure to avoid signal reflections. While the power supply unit on one end of the bus will usually come with an integrated terminator, as is the case e.g. with the 9412 fieldbus power supply, the other bus end in the field must also be electrically terminated. Some devices typically found there, e.g. 9411 Ex i and Ex e field device couplers, feature built-in terminators for activation on demand.
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