stop programmatically voltage acquisition (DAQmx) and plot signal

[Cedric51]

Dear all,

I use Labview 2011 and a NI acquisition board.

I want to acquire a voltage during 5 secondes (sampling=1khz, sample=5000) but I want to be able to stop the acquisition programmatically (stop button for example) before the end of the acquisition. In the case the acquisition has been stopped, I want to plot the voltage data acquired until the stop action. I don’t know if the STOP task is the right function and how to use it. Any suggestions?

Regards,

Cedric

[GerdW]

Hi Cedric,

acquire your samples in a loop: run the loop 10 times and ask for 500 samples each loop. So you will get up to 5s of data, but you're able to stop each 500ms!

Do you get the point? 😉

[camerond]

In addition to what Gerd said, just to make sure it's clear: the STOP task (if you're talking about the big [off-white, ugly] octagonal stop sign) is NOT the correct function. Use a conditional FOR loop and wire your stop button to the regular conditional stop.

Cameron

[Cedric51]

hi GeredW,

The problem with this strategy is that between each pack of samples, there are samples missing because of the loop structure (to go to the next iteration). 

Cedric

[GerdW]

Hi Cedric,

when you use "continuous sampling" you will not miss any samples.

See the DAQmx examples coming with LabVIEW!

[MaveenD]

Yes you can use continous samplying or else use ur graph inside the loop and try it once