why I cannot get response from my USB device through VISA raw using VISAWrite.vi and VISARead.vi?

[BLpig]

I am sure VISA has been assigned as the driver for my USB device (ADC USB FIFO Evaluation Kit). I tried to simply use VISAWrite.vi to send out a word to USB device and want to read the digitalized data from it using VISARead.vi. However, though it seems there are data points flowing, they are all 0-valued coming out from VISARead.vi (I keep reading for N times). Could you comment on my wiring and help me out? I am familiar with LabVIEW but not the real-time and driver things. Many thanks!

[JoshuaP]

Have you been able to confirm that the ADC is connected to a voltage source. What are you expecting to return? I would suggest connecting something like a good 9V battery to the input and reference. Also make sure the reference is either internally connected to ground or you might want to connect a resistor (100kOhm) between the reference and ground.

You might want to try to see what raw data is being returned from the device. Try something like USB Monitor (http://www.hhdsoftware.com/usbmon.html) to see what information is being transmitted between the computer and the instrument.

Did you write the firmware for the device or do you know if the device is suppose to be returning the data from a bulk, interrupt, or control transfer. Also, what is it that
you are trying to create.

-Josh