GET_DAQ_DEVICE_INFO is designed specifically for National Instrument Data Acquisitions devices. This function won't work for 3rd party PXI devices, however NI-VISA will allow you to look at some of the attributes of different devices. Depending on what information you need to find out this may be an option for you. What particular information are you looking to get about your PXI devices?
Trey Hamilton
Applications Engineer
National Instruments
http://www.ni.com/support