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How do i set the chart to show me the results for the last 3 minutes?

I am simulating a data aquiring of 2 pressures and I don't know how to set the chart/graph to show me the results for the last 3 minutes.

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Message 1 of 8

You can set the chart history size to 3 minutes (number of points calculated from the sampling rate), then autoscale the x axis.


( do you really need to [open,read,close] the ini file with each iteration of the loop? Maybe do it once before the loop?)


Also, if you open the data file outside the loop and keep it open during the run, you can simply write at the current position to append. It is also much more efficient to keep the file open.

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Message 2 of 8

I'm new in the domain, so don't judge me please xD. This is a project for faculty, i'm doing it this semester only, I won't see LabView again till next year...

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Message 3 of 8

There wasn't any judment, just some quick pointers how things could be improved.


Is your problem solved?

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Message 4 of 8

So I need 180k points, but i'm still trying to figure out where to change that setting....

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Message 5 of 8

At edit time, right-click the chart and set the "chart history lenght".


However 180k points seems excessive (remember, your chart is only about 200 pixels wide!). What kind of time resolution do you really need? (Sorry, I cannot look at your express VI (NO DAQ installed here), so I cannot tell how it is configured.) What is the loop rate of your while loop?

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Message 6 of 8

The default, 1000

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Message 7 of 8

@TIoan wrote:

The default, 1000

What are the units? How many points do you grab with each read?

What time resolution do you need? How fast canthe pressure possibly change?


You could get 1000 points with each read and only send the average to the chart every second. Now the chart would only need 180 points.

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Message 8 of 8