DAQ card works with NIDAQ test panel but not with VB app/Component works

[dpocius]

I am seeing this problem with 2 different DAQ cards. The card works fine with the NIDAQ test panel, but acts like the return lead is lifted with my VB app. The plotted signal appears to be little more than noise. Channel scan is internally triggered; that apparently works fine. The VB app is running in this configuration successfully in other areas, and I fixed this problem once by swapping cards. Currently, I lack a spare, as my "spare" is showing the same symptoms. Any helpful hints?

Card type: AT-AI-16XE-10
Configuration: Double-ended input, +/-10V range
Running: VB6, NIDAQ 6.1, ComponentWorks Std. 2.0.1, Windows NT 4.0 SP5

[Filipe A.]

Hello;

One thing you might try is to upgrade the version of the NI-DAQ driver that you have installed there. The download is free of charge, and since you are using a fairly old version, that could be a fixed problem on a newer version of the driver.

Hope this helps.
Filipe

[dpocius]

I upgraded to NI-DAQ 6.8.1 (with patch), but no joy. The upgrade went smoothly, the card was recognized and I was able to set the resources without a problem. The test panel works fine looking at the actual signal on the target system: slowly varying DC between 0-5 V or so. My app works fine also, except that it behaves as though the A/D is not connected to anything: noise between .05-.1 V or so. I swapped DAQ cards between the test system and my development system. The problem appears to be in the test system, not on the card. Another test system, identical except for (now) the version of NI-DAQ, works fine. I'm stumped!

BTW, why are there 3 DMA channels listed in the configuration for this DAQ? Do all 3 need to be assigned? I've run some systems
for years with only the first 2 assigned.