Data Collection Delay Issue

[chrisdoe757]

Hello, I am using a labview program (attached) to program two seperate boards wired to 24 mircophone channels to collect sound data from a mircophone array.  I am having a issue where after starting the program the two boards seem to begin taking data at different times although they should both start at the same time.  The set up has one board connected to mircophone channels 1 - 16 and the other connected to the remaining 8 channels.  Each run seems to be different because there is no set delay in time (usually around 3 - 10 ms) and it seems to alternate which board starts first.  With this being my first post I am not sure I have included enough info or descrided the problem accurately.  Please let me know if you need any clarification or additional info.  Thank you in advance for any help.

[Blokk · Accepted solution]

After seeing your VI, some thoughts came to my mind:

1. The delay you see is totally normal, since I do not see any triggering/syncing method in your code. Why do you expect that the DAQ starts at the SAME time for the two boards? A few milliseconds shift between the two DAQ boards is not that bad. Do you need tighter sync (sub-ms)? Then you need some kind of hardware triggering, like a common trigger signal to start the two boards at the "same" time. Available syncing techniques depend on your actual hardware, you can ask your local NI rep for further help (or specify your hardware properly, and someone might help here).
2. You should forget about that silly Flat Sequence Structure, and read about State Machines and how to use them.
3. No error handling implemented.
4. Spaghetti code, and way too large GUI.
5. Learn how to use subVIs, and LabVIEW project.
6. I suggest to take some tutorials. Here is some further readings: http://www.ni.com/newsletter/51735/en/