XP95 Protocol Translator
In order to enable the use of standard control and indicating equipment in intrinsically safe systems, Apollo has developed a device to "translate" voltage levels from anyloop driver operating within the XP95 limits to levels compatible with the I.S. requirements. The translator also"boosts" the current pulses returned by the I.S. detectors from 10mA to 20mA, thereby ensuring compatibility with standard loop driver thresholds.
The translator is a loop-powered device which draws a low quiescent current and is therefore transparent to both the loop driver and the I.S. detectors. Since the translator is used within the safe area, i.e., before the safety barrier, no certification is necessary. The translator falls within the generic description "Safe Area Apparatus" on the certified system diagram.
The translator is housed in a moulded plastic enclosure which can be either clipped onto a standard 35mm DIN rail (DIN 46277) or panel mounted by using pull-out latches in the base. The translator is available in single-channel or dual-channel versions. Each channel should only be connected to a single intrinsically safe circuit through an appropriate safety barrier. Each channel is thus capable of supplying up to twenty XP95 I.S. devices.
