Xy plot properties

Hi There,
I'm relatively new to Labview. I am trying to create an intensity versus position plot. I have a linear actuator moving a laser source toward a detector, as the source get closer to the detector, the detected intensity will rise. So I'm am trying to plot the relationship.
What I need help is how to set the XY plot such that it will only show positive position and intensities regions, and how to keep previous ploted points on the graph as I move the laser source to the detector so I could save an intensity vs position profile.
Thanks a lot
Brian

There are a couple of ways of doing this:
First, if you know the number of points that are going to be displayed beforehand (even approximately) you can pre-initialize an array of that size and pass it into a shift register. As you acquire new data points, insert them into that array and display it accordingly.
The second method, which is much less efficient (causes frequent memory reallocation) requires you to use the Build Array.vi in order to add a new point to your array every time it is acquired.
See the attached example of both of these methods. You will obviously have to modify the code to fit your situation, as I dont know many of the specifics of your application. There are almost definately better ways of implementing what I did, but this is the quick and dirty way. In the event this is not what you wanted, at least it draws a cool shape.
Jeff
Using Labview 7 Express
Attachments:
XY Example.vi ‏66 KB

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When I right click the graph and go into properties, I change the point style to solid circle and turn off line interpolation. I then click save these values as default, and save the vi.
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Solved!
Go to Solution.

HI DarraghCorrigan,
In relation to the problem expressed in your initial post:
"once I run the vi, the graph always reverts plots 1 to 9 (not plot 0, this stays as I want it) to have no points displayed and line interpolation on"
This is due to a bug in the LabVIEW software whereby any changes that are made to the plot properties (e.g. to change the colour of a plot) will not be retained, except in plot 0 which is unaffected. Our R&D department are currently investigating this problem so that it can be fixed in future version of the software. The recommended workaround for this problem is to pragmatically set the plot settings at the beginning of the code using property nodes.
As I understand it, this is not the main problem that you are experiencing. If you set up the properties for a plot (using some of the described property nodes) which is subsequently removed or rewritten on an XY Graph, my understanding is that there is no way that LabVIEW can remember and retain these properties.
As you rightly suggested, one way of conveniently overcoming this problem would be to set default plot properties so that when you remove/rewrite a plot and then add it again, it will always default to those properties. Unfortunately, it is not currently possible to do this though it has been recommended as a product suggestion so it is a feature that is under consideration for implementation in future releases of LabVIEW.
I think the issue you need to be addressing is the fact that you are at some point resetting the graph by sending an empty array to it such that all of your properties are lost. If you can find and remove this section in your code, you should be able to overcome your problem.
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Message Edited by SteveP on 08-15-2009 07:55 PM
Attachments:
LV 2009 3D Plot Axis Autoscale.vi ‏18 KB

Steve,
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is this the result you wanted?
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"I enjoy talking to you. Your mind appeals to me. It resembles my own mind except that you happen to be insane." -- George Orwell
Solved!
Go to Solution.

I went to the graph and made plot legend visible and extended it from one plot to 3. That's all I did. Now it appears to be working properly. It's been a long while since I had to get really fancy with a graph but I don't remember having to do this. My memories of graph properties were that they were a little more dynamic.
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Legend Plots Shown change details

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Michadl,
I can't answer your question specifically, but here's how I set the number of plots and their names in the legend of my graphs from control inputs:
Message Edited by Bill@NGC on 02-09-2008 01:50 PM
“A child of five could understand this. Send someone to fetch a child of five.”
― Groucho Marx
Attachments:
plotattributes.png ‏10 KB
waveformgraph.png ‏45 KB

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plotlegend.vi ‏27 KB

Hi Clement,
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Spoiler (Highlight to read)
Attachments:
graph-legend.JPG ‏66 KB

Gunnar,
You can basically get the sizes and alignations correct by customizing the Plot Legend. Select first the waveform graph itself -> Edit: Customize Control. After that select the first row (See Picture) from the Plot Legend and do the same -> Edit: Customize Control. Now you can type in the long plot name and move the graphics part to the right. Press "Apply changes" often to check if the Legend and its elements are in right place. Finally replace the original control with the customized control.
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Attachments:
Customize plot legend.jpg ‏73 KB

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Hi
In one waveform graph how we can plot two data with different y-axis i.e.. Multiple plots in one graph
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Hi Husssey,
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Solved!
Go to Solution.

Alisha P wrote:
You're right that they don't match the values exactly. It also is completely dependent on how the values are set for your particular color ramp, especially whether or not they are evenly spaced. In your first post, you showed a picture with the colors distributed according to the default. The method I mentioned in the previous post gets pretty close to these values (really a little under each of them - has to do with how the default is distributed).
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Xy plot properties

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