Extract data from XY graph

[GerdW]

Hi mahesh,

next time you should set some typical data as default for the graph…

Right now you use the X-position of each cursor directly to index the data arrays, but that's wrong! The x value isn't the index! You have to filter both arrays (X and Y) to allow only points with X value in specified range…

Are your points stored with increasing X value? Or do you measure them in random order?

[smourad]

hello,

Please how can i extract data from a graph XY?

I want to calculate the variance/average of the amplitude (Y)

thanks

[GerdW]

Hi smourad,

quick&dirty: use a local variable of the graph.

General answer: by using dataflow you don't need to read from the graph! You already have the data available in the wire feeding the graph!

[KAE_DC]

This seems relevant,

http://digital.ni.com/public.nsf/allkb/2AC26660D80E982E862577C9006D6CA3

[KAE_DC]

I am an absolute LabVIEW novice and am struggling with some legacy LabVIEW 6 (2001) code which collects and plots 3 types of data on a 3-line XY multiplot, but crashes before the data is written to an output file. I would like to extract data from the multiplot, and followed this method under "In LabVIEW 2009 and earlier" to copy the graph to a new VI, turn it into a control, and wire it to the 'Write to Spreadsheet File VI' which I did with the wire tool that appears with the spacebar. Unfortunately the resulting wire appears as a dashed line with an error window: "You have connected two terminals of different types. The type of the source is 1-D array of cluster of 2 elements. The type of the sink is 1-D array of single." I am happy with any type of output file (csv, binary, etc), but would like advice on how to convert between the types and wire it to an output.

[GerdW]

Hi KEA,

why don't you attach your VI (or atleast the relevant parts)?

[KAE_DC]

The attached vi contains the multiline graph that I am trying to wire a file output to.