How to extract informations from "AI mult pt" in real-time

[Loris Stehle Orbisphere]

I want to aquire analog data through a NI-DAQ and display them in real-time.
But using the VI "AI MULT PT" from "Data aquisition\Analog input", I fear that data can only be ploted once the VI has sampled the entire waveform.
I know how to extract and use or plot these data before the entire waveform is sampled using the VI "AI ONE PT", but is it possible to do it using the VI "AI MULT PT"?
Is yes, how?

Thank you for any information.

[storeyk]

If i understand you correctly you have an array of data for multiple plots coming from the AI Mult Pt, and you wish to plot these on a chart as and when they are sampled? Well, if this is the case, then add an 'Array to Cluster' function between the AI Mult Pt and the Graph. You need to select the cluster size (right click on the function, select Cluster size, and add in the size of the array).

I have included an example (in LV 6.0) showing an array, but you can replace this with the AI Mult Pt function instead - it should work the same.

Kim

[storeyk]

Oops! I've made a mistake sorry, ignore the above, i misunderstood the question!

The AI MULT PT gathers and reports the data at the end in a waveform, so you cannot acquire the data realtime in a chart. But, you can acquire the data continuously and read one scan at a time, extract the data and display this on a chart. Then you can set the acquisition to stop when you have read enough values.

I have included a NI example (in LV 6.0) of continuous acquisition. Let me know if you have any problems adapting this idea to your needs.

Kim

[chucky9]

Hi Kim,

I'm in the process of upgrading some older DAQ cards, MIO-16e series, to NI-USB-6529 series. VIs were writen using traditional driver for the older DAQ and now I've to convert them to DAQmx. I ran accross one of the VI used AI one PT and AI mult PT form traditional driver, can shed some light as to how convert these sub-VIs using DAQmx driver.

Thanks,

Chucky

[GregFreeman]

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@chucky9 wrote:

Hi Kim,

I'm in the process of upgrading some older DAQ cards, MIO-16e series, to NI-USB-6529 series. VIs were writen using traditional driver for the older DAQ and now I've to convert them to DAQmx. I ran accross one of the VI used AI one PT and AI mult PT form traditional driver, can shed some light as to how convert these sub-VIs using DAQmx driver.

Thanks,

Chucky

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Chucky, this thread is over 10 years old so I bet Kim isn't around  much anymore . It's much easier with DAQmx. You will want to replace these functions with DAQmx read, and select the correctly polymorphic instances for the tasks you have set up: either single channel single sample or single channel multiple samples (or some other variation if you have multiple channels also). I would suggest looking at some examples that ship with LabVIEW. You will find the DAQmx driver to be far less cryptic than the legacy DAQ.