Hi,
Are you getting any errors?. My guess is that you are getting the timeout error from the VISA read VI. If this is the case, you should look closely to the command string you are sending to the instruments, specially if you are attaching the termination characters expected by the instrument.
If you don't attach the termination character, the instrument do not detect that the query command ended, so it doesn't return any data.
DiegoF
National Instruments.
