graph and samples

[BjarneDK]

Hi,

Im working on a bigger program, were Im using a DAQ assistant, graphs and other things. Now the problem is that I dont know how to get the graph showing more than the 100samples at time. I have tried to use a collector VI, but it makes some conflicts with my program. I also try to avoid too many shift registres. Any suggestions?

I attach a simple VI to show what I mean 🙂 I hope that any have an idea.

[Andy_C.]

Using a Chart should solve your issue.

[jcarmody]

Change the graph to a chart.

EDIT - I need to learn to type faster.  And Andy even included a VI.

Message Edited by jcarmody on 05-04-2010 02:36 PM

Message Edited by jcarmody on 05-04-2010 02:37 PM

[BjarneDK]

Thanks, I tried that one to, but I have another problem. If i use a chart, how do I then convert the samples till time? F.ex. a chart showing 0 to 5sec (thats why I thought that a graph would be better:-)).

[jcarmody]

Use Append Signals?

[NIquist]

Technically, you can't.  A chart simply takes in a datapoint (Y value) and plots it.  There is no inherent timing information stored.  If you are sure that every point in the chart history was collected at the same time interval you can create a waveform with timing data using the "Build Waveform.vi".  Wire the output of a History Data property node to the Build Waveform Y input, the timing interval you collected at to the Delta T (dt), and zero to the start time (t0). 

[BjarneDK]

Im a bit confused 🙂 which one is best appended or build waveform?

[NIquist]

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BjarneDK wrote:
Im a bit confused 🙂 which one is best appended or build waveform?

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It depends on your application and your programming skills/preferences.  I was just providing general info about the differences between charts and graphs and how you could use a chart to get graph-like data.  Conversely, you could make a graph act like a chart by storing your data in an arrray and then using the array to "update" the graph after each data collection. 

Now you're a "bit MORE confused" I bet.    I'd need to see your code to be more specific and I can't open above LV 8.5.1.  If you want to post a JPG maybe I could see what you're doing and give some more specific advice.

[BjarneDK]

can you open 9.01 thats were I made the other one 🙂

[NIquist]

No sorry (9.0.1 > 8.5.1 ).

I looked at the code in the second post (from Andy C.) though and I assume that you've just provided very simple, stripped down code to explain your issue.  I suspect your "collector VI" is the faking a chart with a graph trick I mentioned previously.  That is the way many people do what you seem to be wanting even though it involves building an array in a loop which can be memory intensive.  Why didn't it work for you?

This is what I meant by using the chart history data to generate a timed waveform.  See if it helps.