This particular application was designed to control the progression of snow rafts at a mountain resort, but is easily adaptable for other applications that require process control.
For this application at a mountain resort, snow rafts begin at the top of one of a number of gated slides. The gate is open by default. When the raft moves past the RFID reader at the top gate, the reader reads the RFID tag information and sends a signal to a PLC which in turn sends a signal for the gate to close preventing other rafts from using the slide. When the raft arrives at the bottom, the tag is read by a second RFID reader which sends a signal allowing the PLC to open the gate for another raft.
Main Hardware Installation Concerns: Climate was a concern in this application as temperatures can reach as low as -40°C, there are also often harsh winds and blowing snow. Also sled speed can reach up to 80 km/h. Consideration also had to be taken into account that the multiple readers at the top of the hill would log the correct shoot for the raft.
System Components: The system uses GAO 236015 UHF Gen 2 RFID Reader/Writer with 4 Antenna Ports and GAO 236018 UHF Gen 2 Fixed RFID Reader/Writer with 2 Antenna ports along with Class 1 Gen 2 Passive tags. GAO LocateWare 3.0 is used to control the RFID readers and the PLC devices and to record the data into an SQL server database. The software interface reports on Raft and slide information, tags assigned to the rafts, raft location and speed display.