Continuous synchronized AI and AO on TWO M-series PXI-boards

[einarsto]

Hi, there!

I have just succeeded in performing continuous synchronized AI on two PXI-boards (6229 and 6259) using the PXI_Clk10 backplane clock. My application is also supposed to generate continuous analog output through one of the boards. I have written both applications in separate projects and they work fine, but when I combine the AI and AO code in one VI and try to run it on the PXI-target, it fails. The AO starts, but the synchronized AI never gets past the first loop iteration.

Only one error message appears; labview claims that "..not all samples have yet been acquired". My bet is that this has something to do with a sample clock/Reference clock conflict. For the AO I left the source-terminal of the DAQmx Timing VI unwired to let labview choose the default AO sample clock. This should not be in conflict with the AI performed by the same card....?

I would be grateful for any help. Labview has an example of multi-function AI/AO, but this code seems to do things much the same way that I did. I will post my code as well when I'm back at work on Wednesday.

Einar

P.S. The AO does not have to be synchronized with the AI.

[Jimmie_A.]

Hello!

No code has been posted as of yet so I suppose that means that you have solved the issue, is that a correct assumption?

[einarsto]

Hi, Jimmie!

Yes, I solved the problem by forcing the AO-task to start after the AI-tasks, but I'm not exactly sure what caused the initial conflict.

This didn't get me very far, however, as my pxi-system couldn't handle the workload of sampling 32 channels at 10 kHz while running the 10kHz timed loop containing point-by-point VI's that created the output.

...but that is another story 😄

Einar