XY graph cursor position bug

I have reproduced the bug mentioned here:
http://forums.lavag.org/Graph-Cursor-XY-Position-Bug-t1366.html&gopid=40859#entry40859
I've reproduced this bug (?) in Labview 8.5, with an XY graph doing
much the same as Jack. The attached zip file contains a stripped down
version of my program (originally written by my coworker, Andrew
MacDonald). Run "RENA3 Data Viewer.vi" and follow the instructions.
As Jack said, changing Cursor.PosX to Cursor.Index solves the problem.
I did not find this bug mentioned anywhere other than the above link.
Fraser
Attachments:
XY Graph Cursor Bug.zip ‏142 KB

Hi Karla,
Sorry if that wasn't as obvious as I thought! :-) Hopefully the attached image makes it clear. On the front panel, 'Cursor Channel' is inputted. This is directly wired to Histogram.Cursor.PosX. Immediately following, Histogram.Cursor.PosX is read and wired to the front panel indicator 'Cursor.Cursor Position:Cursor X'. There is always a difference of 15 or 16 between the two values. If there was no bug, these two values should be identical! I can only conclude that Labview is doing something funny...
As I mentioned before, changing Cursor.PosX to Cursor.Index fixes the problem.
A bit of background: my FWHM function outputs the peak channel, and the cursor is supposed to go through the peak so you can have a visual check that it is analyzing the right peak. I noticed that the line would never go through the peak; the line would always have an offset. After wasting a couple of hours, it became clear that I was wiring the correct value into 'Cursor.PosX', but something was going wrong beyond that.
Cheers,
Fraser
Message Edited by fjharris on 01-25-2008 11:34 AM
Message Edited by fjharris on 01-25-2008 11:36 AM
Attachments:
Labview Bug.png ‏27 KB

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"Greg McKaskle" schrieb im Newsbeitrag
news:[email protected]..
> > I try to catch an event when the cursor position of a graph's cursor
> > changes. I created a reference for the cursor array and registered a
dynamic
> > event 'Value change' for it. The event does not fire when the cursor
changes
> > (either by dragging it with the mouse or by direct entry of a new value
in
> > the cursor's X or Y fields. In contrast, when I register e.g. the 'Mouse
Up'
> > event for the cursor array, the event IS detected.
> >
>
> The reason is that value change events fire when user action directly on
> the control changes its value. They do not fire when other programmatic
> value changes occur. If you are looking at a value change on the cursor
> palette, user interaction with the numeric should fire it, but updates
> due to cursor movement are more like programmatic updates.
>
> Additional events will likely be added in future
releases, and these may
> make it easier to catch cursor movement events on a graph.
>
> Greg McKaskle
>

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Solved!
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Go to Solution.

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Solved!
Go to Solution.
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My Source Distribution.zip ‏541 KB

bracker wrote:
I'm trying to use property nodes to set the cursor position programmatically, following an arrow keypress. When my actual data file plotted, the position assignment doesn't work properly. If I clear the data from the graph (right click, clear graph), then the cursor responds properly. I've attached a zipped file with VI that demonstrates the problem. Sorry the file is large--I had to include my data file to properly demonstrate the problem.
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XY graph cursor position bug

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