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extract xy graph's data from generic cursors

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Hi,i'm new in this Forum.

In my VI i need to extract xy graph's data from a cursor to another one,how can i do that?

I want to extract all the data between the two cursors,for elaborate it.

Thank you 🙂

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You need to show us what you have. Please attach a simplified version of your VI containing typical data.

 

  • Are the x value sorted or random?
  • Are the x-values spaced equally?
  • What is the datatype of the graph data?
  • You also need to explain what a "generic cursor" is. I am not familiar with that terminology.

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Ok i create this VI because it describes perfectly my situation. 🙂

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All the answers are in the VI 😉

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  • You have a race condition due to overuse of a local variable. Most likely the local variable is read before the graph is written.
  • Why is there no outer loop? Are you using "continuous run mode???)
  • Your two array don't contain any default data. After you place values into them, you need to make current values the default before saving the VI.
  • You code inside the FOR loop makes absolutely no sense.

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Solution
Accepted by topic author giacom9222

In addition to everything altenbach said, you want the Cursor List: Index property. That will tell you where in the array of data the cursors are.

 

The attached VI shows how it can work and also how meaningless it can be with common types of XY data.

 

Lynn

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Ok sorry,this version is better.I don't need while loop here,this is only a very small part of my program.
It works,but i can't undertand why it not extract the data correctly...in the graph with the extract data i don't have the portion between the two cursors!

thanks for your time

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For xy graphs, the array index has no relation to the x values and your subset makes no sense. You need to check if the x values are in range and discard if they are not. Here's a quick draft.


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Message 8 of 10
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Thanks John,you solved my problem 🙂

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Message 9 of 10
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@giacom9222 wrote:

Thanks John,you solved my problem 🙂


Well, you required "from generic cursors", while Lynn's code uses cursors locked to a plot (as I already suggested here).

It only works if the X-values are sorted, and this cannot be guaranteed in the general case. (have you tried the "random" option in Lynn's code 🐵

 

It seems wasteful to get the entire cursor list if all you want is the cursor index.

You should also use the max&min function as I suggested. This way the two cursor positions don't need to be sorted.

 

Also note that if you would use complex data as I suggested, you would only need a single array subset operation, simplifying the code.

 


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