I hoping someone can help. I have been out of the ATE/Labview game for quite a few years but have recently developed an application where I am measuring two DC power supplies outputs using LV 2012. The card I am using is an older PCI-6014 and I am only using Ai0 and Ai1 as 2 analog inputs. The problem is they seem to measure ok but every minute or so the measurement drifts like crazy for 5 - 10 seconds then returns to normal. When I monitor with a scope the 2 supplies I am measuring are rock solid, so I figure I must have a config, sampling, grounding, or biasing error of some sort. I have tried every possible config for this card, Diff mode, NRSE mode, bias resistors, no bias resistors, different sampling rates.......no luck still getting the same result. I tried connecting just a battery to one input and the measurement stayed rock solid, so I am guessing a grounding issue. Strange cause you would think the card would see a DC input the same weather it is from a Power supply or battery. Any thoughts?
These are supplies I am measuring
http://www.productselection.net/PDF/UK/spd5w.pdf
