I have a USB rain gauge that I would like to monitor using LV. Do I need an additional hardware card or can LV read/monitor a USB device without any additional hardware?? I know this a vague question and I'm looking to get more info. Thanks.
If the USB has been implemented as a USB to RS232 converter, then it would be detected by windows as another serial port. You could then use VISA to read/write to it as you would any other instrument connected to a serial port. If the manufacturer did a custom driver, then you would use the Call Library Function to interface to their DLL. Of course, you would need documentation from the vendor on the DLL. Current versions of LabVIEW and VISA have USB functions but using raw communication requires even more information from the vendor and this is sometimes hard to get. So, first see how Windows detects the device and how it's listed.