USB DAQ interferes with USB Serial port

[sth]

Here is an even more stripped down version and a clue as to where the problem lies.

VI #1 does no serial interactions at all and is pure DAQ.

VI #2 when run (and sometimes it takes 3 times) freezes the DAQ loop in the separate VI.  It seems to be in the "Find First Serial Port" vi that does a VISA search.  So my thesis is that the the VISA find operation interferes with USB-DAQ.  I think it is time to start an actual service request for this "bug".  There is no reason that a VISA search should hang other LV operations.

Possibly it is locking up the USB bus in a rather agressive manner?

[sth]

I have now reproduced the problem with the NIDAQmxBase example, "Cont Acq&Graph Int-Clk.vi".  When I use that with default settings while recording 3 channels it hangs and reports data not available when running the attached VI.

The attached VI has no subroutine calls and merely does a VISA search and opens ports until it finds the correct port.  This is about as minimal a test as I can do.

[johnsold]

Scott,

Your hypothesis seems plausible.

I cannot really tell anything because I do not have any DAQ devices.  I should save a few pennies and get something.

Lynn

[sth]

Lynn,

Thanks for looking at it.  I have an open service request.  I am getting all sorts of odd errors with VISA, and not sure why.