synchronize two USB Daq's

[DMBS]

        I have two NI USB-6218 Daq's running under NI-DAQmx in Win XP.  Is there an easy way to synchronize the waveforms from both collected from the AI's.  Calling DAQmxStartTask() in sequence for the two of them seems to separate the two daq's in time by about a tenth of a second, but it varies a lot due to XP. 

[Yardov]

Hello DMBS,

Any method that used the internal clock should not be OS dependent and you should be able to get consistent results. Regardless of that, I hope you can read this Developer Zone document where you can learn about M-Series (like the one you have) Synchronization.
There is a shipped example called "Multi-Device Synch-Analog Input-Cont Acquisition.vi" that you can find on LabVIEW example finder. This will not work immediately but it is a good starting point. You will need to share the Trigger using a PFI line and use some external wiring.
If you sample at the same rate, you can just import your sample clock to a PFI line. Once those two signals are connected, you should be good to go.

Hope this helps,

Message Edited by Yardov on 09-12-2007 01:23 PM