Build XY Graph express vi for multiple plots in one graph

[girish53]

I like the Build XY Graph express VI, because it allows me to add one point at a time and it incrementally plots the new point. However, it allows only one plot in XY graph. If I want to have two or more plots in the same XY graph, is there an equivalent of the Build XY Graph express vi? Any other alternatives.

Thank you.

Girish Joglekar

[GerdW]

Hi Girish,

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@girish53 wrote:

is there an equivalent of the Build XY Graph express vi? Any other alternatives.

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Use a shift register and BuildArray...

[altenbach]

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@girish53 wrote:

However, it allows only one plot in XY graph. If I want to have two or more plots in the same XY graph, is there an equivalent of the Build XY Graph express vi?

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This is incorrect. The build xy graph express VI allows multiple graphs.. By default, the inputs are dynamic data, which can have one or more signals. 

[altenbach]

Most advanced LabVIEW programmer stay far away from express VIs and dynamic data, but as a proof of concept, here's one possibility how it could be done.

(Of course this is a silly example, because x are spaced equally, so  chart is all that's needed)

Now forget about all that and implement your own using simple datatypes. 😄

[girish53]

I tried giving elapsed as X Input, and a cluster of two values (corresponding to two variables I want to plot) as Y Input, but it gave me an error. See below.

How do I input the two y's and one x to the Build XY Graph.vi?

Thank you. 

Girish

[GerdW]

Hi Girish,

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@girish53 wrote:

How do I input the two y's and one x to the Build XY Graph.vi?

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Did you look at the example you got from Christian?

He showed you two ways to create inputs for two plots…

[girish53]

Thank you very much. It worked the way you showed in the example. My next challenge is: Would it be possible to fix x min,max, and y min,max so that the graph keeps growing steadily instead of readjusting every few time intervals? I tried setting the corresponding plot properties before starting the while loop which generates the points. But they were completely ignored.

Girish

[GerdW]

Hi Girish,

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@girish53 wrote:

Would it be possible to fix x min,max, and y min,max so that the graph keeps growing steadily instead of readjusting every few time intervals? I tried setting the corresponding plot properties before starting the while loop which generates the points. But they were completely ignored.

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Why do you want to change plot properties when you want to set axis properties???

Which plot properties do "correspond" to axis ranges?

Solution: to "fix axis ranges" you switch of axis autoscaling and set the desired range…

[altenbach]

You can turn of autoscale for the x axis and set the lower and upper limit to a reasonable value corresponding to the expected range. Of course once X is outside these boundaries, you won't see that data.

[BuddyHaun]

Build the x-array and y-array for each channel into its own cluster then build an array of these clusters. Feed the array of clusters direct into the XY Graph