Real time display inside a loop

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Another question of the day. I am doing two voltage sweeps (source-drain, and gate voltages) using two while loops. I break my questions down to four points.

1. I can display I-V curves in real time use what I have now. But I would not be able to see all the curves (at different gate voltages) in the graph, as the data is erased after each loop.

2. I can display all the I-V curves together if I put the graph outside of the loop using autoindex. But I would not be able to see the curves in real time.

3. Someone suggests to use chart instead of graph. But I could not wire the bundle to the chart.

4. Is there a way to display the curves in real time inside a loop and keep all the history data?

Thanks.

[Will.D]

If you bundle the two arrays, still as doubles, as you have where you wire it to the "To spreadsheet file", you can wire the 2D array to a Waveform Chart. To obtain the history outside the loop, all you need to do is right click the waveform chart->create->property node, and then you can access "History Data" from there. Also, on the front panel, you can right click on the waveform chart, and set the "Chart History Length" to include as many points as you need. It's best to not make this number much larger than you know you're going to need though, since I believe it reserves the memory for whatever size you specify, regardless of whether it's used.

Hope this helps,

Geoff

Attached is a vi that better demonstrates the above.

Message Edited by Novatron on 06-28-2005 03:50 PM

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Could you put your diagram in jpg or png? I can't read your example as I am still using LV6.0.

I tried to wire the bundle to chart. It didn't work as I don't realize chart take double only. But right now, I get another problem, the x-axis in waveform chart is time by default. But I need it to be voltage. How can I change that? Thanks again.

[altenbach]

You cannot use a chart, because you have x-y data.
(If your x-data points are equally spaced (are they?), you can use a chart and graph only the y. You can set x0 and dx as desired using proerty nodes).

Have a look at the example program xy-chart for some ideas (I am not sure it it was available in LabVIEW 6.0, but use your example browser to see).

In any case, you would need to simply build up the historic traces in a shift register, then merge the old a new data for display. Shouldn't be too hard. Let us know if you get stuck. 🙂