Trust me on this, every time you design, build, or make anything, the first and most important thing is to do the simplest test before anything else. This may sound (dare I say) foolish, but in my 35 years of working as a technician in a factory to a few R&D labs from a medical device company to Apple computers (and many other jobs in between), I have never seen a product go straight from design and build to use. What I mean is that if you make a radio, don't try to see if it gets fifty channels, before everything else see if it turns on, just turn it on and off a few times.
Now back to our main topic. I have one or more measurement computing DAQs. Although the main purpose is to use LabVIEW with these devices, first start by installing original software that comes with the device and see if the device is functioning as it should; from the MOST SIMPLE task to putting the device through the most complicated ones for a long period of time. Another point to consider is...