It's not quite that simple. What is the device you're speaking of? Is the device USBTMC compliant? If so you could communicate with it in a way similar to GPIB instruments - you send a command, and you read a response. You'd need the documentation on the command set. If it's not USBTMC compliant then you'd need to either get a DLL from the manufacturer, or you'd have to use USB RAW. In order to use USB RAW you'd need to have detailed information from the manufacturer on the data packets, and this is not something they're likely to give out.
Also, please try a search next time and read up on information that already exists in the KnowledgeBase: USB Instrument Control Tutorial.
