Graph cursors displayed against wrong Y-scale

[eberaud]

Hi,

 

My graph is a XY Graph but the X-scale is just the time. I use the XY Graph in order to define the time stamp of each sample. I use cursors that I snap to the plots in order to display the plots' names. Everything works well when all the plots are displayed against Y-scale 0. But when switching a plot to Y-scale 1, the associated cursor keeps moving like if its plot was still on Y-scale 0. Simply dragging the cursor with the mouse a little bit snaps it to its plot properly (value displayed against Y-scale 1).

 

I tried using the Cursor.YScale property of the cursor but it doesn't seem to help.

 

Has any of you encounter this issue?

 

I am using LV 2011.

 

Thanks!

[Porter]

Reproduced on LV2013. See attached VI. Changing the Y-scale of the plot during run-time should reproduce the problem. It seems that the cursor's y-scale is not updated until you move the cursor manually.

 

 

A workaround is to catch the plot attribute change event and update the cursor list manually. I've implemented this in the attached VI. Enable the Fixit? button and then change the plot's Y-Scale and the cursor should snap to the correct scale.

 

The attached VI is saved back to version 2011. Let me know if it works for you.

 

Ok... I can't attach files... Here it is in dropbox: https://dl.dropboxusercontent.com/u/8640811/XY%20Graph%20Bug/XY%20Graph%20Cursor%20Test.vi

[eberaud]

Thanks Porter that looks very promising!

 

I haven't found time to try it inside my code yet but will do very soon and will get back to you.

 

Cheers

[eberaud]

Just tested it within my code. It works! But what made it work is setting the X-position to 0. I removed the update of the Y-scale property of the cursor and it still works. On the other hand, if I leave the Y-scale property and remove the X-position of the cursor, the fix no longer works.

 

It's strange, I would expect the X-position to be useful in Free mode only, since I use the Index property to specify the point of the plot to snap the cursor to...

 

Anyway, thanks again Porter, this bug had been bothering us for weeks...