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A kind of intensity plot.

I am completely new to LabVIEW. I would like to read in a tab-delimited txt file with about 80 columns and 560 rows of data. When a particular piece of data is above a certain "limit," I'd like to plot a '+' sign on a cartesian plane. When the data is below another "limit," I'd like to plot a '-' sign. When the data falls in between the two limits, I'd like nothing to appear on the cartesian plane.

I think I can handle opening the text file, but how should I read in the data. Then, how do I use the 'draw text at point' tool when the value is outside certain limits? Again, I have no experience with LabVIEW in terms of arrays and things. Any ideas on a path forward, where I should start, and how to do what I'm trying to do?

The txt files contain thickness data across a sheet of product. The product has 560 data points across(X-axis) and 80 sets of data from top to bottom(Y-axis).

Thanks
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Message 1 of 4
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You can read and write the file on the mentioned format with no problem. You can see my quickly made example doing that.

If you wanna use a graph I don't think that you can use different symbols (+ and  -).

I didn't understand all the things that you wrote. How do you wanna plot the points? you have a 2D array and then how do you put each of these point in X and Y axes?

Software developer
www.mcm-electronics.com





PORTUGAL
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Hi CrAyZ,

To read the tab delimited txt file, you may want to use the "Read from Spreadsheet File.vi" This will give you an array of data to work with. Once you do this, you will be able to extract the data required using the various array functions. Once you have done this you can split the arrays into 3 (one for "greater than your value", one for "smaller than your value" and one for in between). I would probably use an XY graph. Also, you will need to use property nodes to change the appearance of the plot and points. In other words assign a + symbol to the array of greater values (property Plot.LineStyle= 11 for this case), - symbols for the array with values less than the limit, and blank for the values in between. It appears that you will not need a line connecting the dots so this should be acceptable.

Also, for your reference since you are new to LabVIEW, here are some good LabVIEW resources that you may want to take a look at to get a good basic overview.

LabVIEW fundamentals in DevZone:
http://www.ni.com/devzone/lvzone/fundamentals.htm

LabVIEW introductory course:
http://zone.ni.com/devzone/learningcenter.nsf/03f7c60f17aad210862567a90054a26c/60c2782788a811c986256cd50001a0a6?OpenDocument&node=200067_us

Top 10 Requested White Papers and Tutorials for NI LabVIEW:
http://digital.ni.com/express.nsf/bycode/exzsvg

LabVIEW Strings, File I/O, and Property Nodes

http://zone.ni.com/devzone/cda/epd/p/id/3843

I hope this helps. Have a nice day!

Best regards,

Steven
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Hi CrAyZ,

      Here's a very simple example of how to accomplish what you asked.  I used the "Read From Spreadsheet File.vi" - like Steven suggested - and wrote to a picture-control since you mentioned "draw text at point." Smiley Wink

Hope it helps!

"Inside every large program is a small program struggling to get out." (attributed to Tony Hoare)
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