hardware trigger causes shift register failure

[RotorcraftJoe]

I got an interesting problem. I've got a case statement that contains the AI Start.VI out before a while loop that contains AI Read.VI and some processing. The case statement with the AISTART.VI, depending on the case, will either start immediately, or start upon reception of an analog trigger. I've also got a couple waveform graphs inside the loop that update every loop iteration with different running averages. These averages are kept in shift registers that are initialized from outside the loop before the first iteration. When the case is set to immediately aquire, these graphs update beautifully. If the case is set to wait for the trigger, the trigger begins the acquisition nicely, but these graphs that are connect
ed to shift registers never get data! Other graphs not dependent on shift registers still update every iteration. Any ideas on what in the world is up here? Thanks in advance for any help!

-JOE

[Ben]

Just a guess here.

Create an indicator for the shift registers. There may be data in them that is confussing the graph.

Ben

[crelf]

G'Day Joe,

Please post up your VI - your problem sounds interesting...

cheers,
Christopher

Christopher G. Relf
Certified LabVIEW Developer

Christopher.Relf@mBox.com.au
Int'l Voicemail & Fax: +61 2 8080 8132
Aust Voicemail & Fax: (02) 8080 8132

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[RotorcraftJoe]

sorry, I tried to upload the VI, but it's 30 megs and it seems the internet is putting up a fuss about it. The best I can do is offer a more detailed explanation.
-JOE

[Zvezdana S.]

Joe,
Strip down your VI into a simpler example that shows the behavior. Have just AI start, read and clear, with structures and one graph. This VI shouldn't have more than few megs. Test this VI, and if it reproduces the behavior, post it on the web. Run the VI in the highlighted execution mode or put a probe on the shift register, and see if there are values being written to it in each iteration.

Zvezdana S.