Excom is a remote I/O system for use in hazardous locations consisting of power modules, PROFIBUS®-DP communication gateways, I/O modules and a backplane rack. The backplane rack is available in two sizes, with support for 8 or 16 I/O modules. The larger rack (MT18-) also allows for redundant power supplies and/or PROFIBUS-DP gateway cards.
The I/O modules provide the interface to field devices. The backplane distributes power to the I/O from the power supply, with no need for a separate field supply.The gateways, power supplies and I/O cards are simply plugged into the backplane rack, with all power, PROFIBUS-DP and I/O wiring separate from the removable modules. I/O modules may also be changed during operation ("hot-swappable"). The system automatically checks whether a newly inserted module matches the configuration.
When the excom system is used, the PROFIBUS-DP segment coupler SC12Ex must also be used for the interfacing. The coupler is equipped with one standard RS485 interface and two RS485-IS interfaces that allow redundancy. Optional fiber-optic couplers are also available.
The excom system, (including the SC12-Ex segment coupler) can be mounted in Division 2, Zone 1 or 2 and is FDT/DTM and HART compatible. The field circuits are approved for Division 1 and Zone 0.