XY Graph Tracing

[Sidelingscroll]

Hi all,

I had a program where I read out an ascii tab-delimited, two-colum file.  The first column contains X values.  The second column contains Y values. I would like to construct a program which traces out this XY plot and outputs the last value.  Everything is working like a charm except the graph is totally blank, and I can't understand why. Any help is appreciated.

Thanks in advance,

NSG

[altenbach]

You did not include a datafile.

How many points are there?

Maybe you want a plot that shows points instead of connecting lines? (a line needs at least two points to show!)

What should happen when you run out of points?

[Bob_Schor]

• Right-click on the Array Subset function, choose Help, and read the Help Message.
• Don't use Express VIs, don't use Dynamic Wires
• If you've got a 2-by-N array, you should be able to pull out X-Y pairs.  If you've got X-Y pairs, you should be able to figure out how to plot them.
• Take the LabVIEW tutorials (upper right corner of the Forum home page) if you are just beginning.

Bob Schor

[altenbach]

Try something like this....

Some additional comments to your origianl code:

• Don't convert the same string array to a DBL array with every iteration. This belongs outside the loop. (Well, the compiler will probably do the right thing by eliminating loop invariant code, but still...) 😉
• Use the correct representations, i.e. don't mix blue and orange for the indices.
• Don't maximise the front panel and diagram to the screeen. that's very annoying!
• Don't use dynamic data and express VIs as has been mentioned.

[Sidelingscroll]

Oh cool I appreciate it.  I have attached the data.

With the plot I meant that I wanted the graph to trace it out but keep the trace, not just roll with a single point but hold onto the it as it goes through the entire voltammogram I have attached.

Thanks again.

[altenbach · Accepted solution]

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@Sidelingscroll wrote:

With the plot I meant that I wanted the graph to trace it out but keep the trace, not just roll with a single point but hold onto the it as it goes through the entire voltammogram I have attached.

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Like this, maybe?

[Sidelingscroll]

That's great.  Here's my final program and text input file (I had to multiply the values in the second column by 10^6 to get them to display correctly, but that's ok)