The excom System
excom is a Remote I/O System for use in hazardous locations. It provides PROFIBUS -DP compatible I/O modules in an IP20 protected solution for connecting discrete and analog intrinsically safe field devices. It is approved for use in Class I, Division 2 locations, and may be connected to field devices in Class I, Division 1 areas.
The modular system consists of power modules, PROFIBUS-DP communication gateways, I/O modules and a backplane rack. The backplane 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 PROFIBUS-DP gateway cards to be used. This allows a failsafe communication scheme to be used.
The I/O modules provide the interface to field devices. The backplane provides power for I/O from the mounted 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-swapped"). The system automatically checks whether a newly inserted module matches the configuration.
The internal cycle time of the excom system is less than 5 ms for discrete signals and less than 20 ms for analog signals. Total response time of the PROFIBUS-DP system depends on the cycle time of the controller and its program, as well as the data rate of the PROFIBUS-DP system. HART values may be exchanged with supported devices via PROFIBUS-DPV1 communication.
In order to use the excom system in a hazardous area, the PROFIBUS-DP communication must be conditioned through a segment coupler. Couplers are available for both wire and fiber-optic media.
The excom gateway provides extended PROFIBUS-DP diagnostic information, including channel-specific error indication. Each module also features LEDs for visual error indication as well as I/O status. Consult the user manual for the excom system for detailed information.
The I/O modules need no user configured address since the gateway recognizes them by which backplane slot they are inserted in. The excom system itself needs a PROFIBUS-DP address, which is set via three rotary switches. The maximum address of the system is 125.