There are 3 models of UV sensors that are currently compatible with XTension and the RFX Comm Receiver.
They send only a single command and require 1 unit in XTension. When you power up the device it will begin sending updates to XTension which will appear in the log. You can get the address that the device has set itself to from the log entries. Create a new unit in XTension, assign it to the RFX interface and enter the address you got from the log entry. Choose a device type of UV Level and save the unit. It will begin receiving data from the device the next time it transmits, which should be about every 30 seconds or so.
The values sent are from 0 to 16.
If you have XTdb installed the readings will automatically be saved to the database and you can create graphs of the data. Here is a graph that I plot the UV levels along side just visible light flux as read by a CDS cell on the roof plugged into a Weeder Anaglog Module