AI Start and Error -10609

[timpy]

Hi

I'm running SCXI 1100 and 1126 modules in a SCXI 1001 rack, on a windows 2000 SP3 PC using a 6052E NI DAQ card, LV 6.1 and the latest NIDAQ.

I am trying to configure, in parallel, the AI aquisitions for the 1100 (AI) and the 1126 (frequency)modules, both at the same scan rate, but whenever the second AI Start is run I receive the Error -10609, Transfer in progress error. They each have a seperate group number at AI Config and the AI configs generate seperate Task ID's for them. I configure both, then try to start both.

Effectively I suppose I'm trying to start the card twice I imagine. AI start is the only problem, and can't currently see a way round it. The shipped examples run either one or the other, and work fine (naturally
enough).

Many thanks for any help.

[markwysong]

This cannot be done with two AI Starts trying to run buffered acquisitions on the same SCXI chassis.

You will need to combine your channels into one acquisition to perform this function.

The SCXI multiplexes all input channels in its slots to one channel, and that channel is then routed to a single channel on your 6052E MIO card. Therefore, by trying to run two separate buffered acquisitions, you are trying to add channels to the multiplexing while the multiplexer is running, which results in an error.

Mark

[timpy]

Thanks Mark, I'll give it a whirl and see what happens.

The only potential problem I can see is trying to set up the triggering for the 1126 only, as I can't see any specific channel specifiers for the Trigger Config vi. I was worried about the 1100 adopting these parameters as well as the 1126 which is why I tried keeping them seperate. Any thoughts on this or am I worrying over nothing?

Thanks again for your reply.

[markwysong]

I'm assuming that you're triggering on a channel on the 1126, and then reading data from both SCXI cards?

If that's what you are trying to do, your best bet is to use a software trigger. It's an input on the AI Read.VI, where the AI Read VI reads data from the buffer, but if a trigger condition isn't met, it returns nothing.

There's an example under LabVIEW 6.X\examples\daq\anlogin\anlogin.llb called Acquire&Proc Scans - SW Trig VI. You can adapt this to continuous if you want.

Mark

[timpy]

Thanks Mark for your help.