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2D plot of current position without traces
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sbuczkowski
post Mar 4 2010, 05:47 PM
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Hello,

I'm working on my first project with DAQFactory Express and have run into an issue that I have yet to find a solution for. I have two voltages being measured by a LabJack that represent X and Y position of a laser beam on a detector. I have a 2D graph set up with each axis representing one of the voltages but i would like to see just a symbol denoting the most recent measurement. What I have is a trace of the position history which gets messy after a short while.

Is there anyway to turn off the old data and just display the most current data point with a symbol?

Thanks!

steven
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AzeoTech
post Mar 4 2010, 09:16 PM
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Two things:

1) to limit the data being plotted, subset one of the two expressions. For example, to just display the last 100 points, add [0,99] to the end of the Y expression
2) to put a point at the end you actually have to create a second trace and put that trace on another axis (probably a right axis), setting that other axis to point instead of line. The second trace has to have two points to plot (I believe), so make the X and Y expression something like:

concat(ychan[0],ychan[0])
concat(xchan[0],xchan[0])

You also might not need two points for a point, so try just doing [0] first.
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