Event structure and waveform graph cursor

I am utilizing a waveform graph and I need to programatically manipulate multiple cursors based upon the movement of a primary cursor. I would like to use the event structure to avoid processor usesage.
My approach is to create an While Loop/event structure where it goes into a it when there is a "mouse down" on the waveform graph. Once in it, there is another While Loop/event structure that has two cases: Time Out (set to 25) and a "Mouse Up" on the waveform graph. In the Time Out case, the primary cursor is read and modifies the location of the secondary cursors. In the "Mouse Up" case, the primary cursor location is read, other cursors are manipulated, and the While Loop is exited.
When I code this up and perform a "mouse down" on the waveform graph, the index on the inner While Loop/Event Structure is advancing but there is no control (can't move it) of the primary cursor on the waveform graph. When I "Mouse Up", the inner While Loop exits.
Obviously, my approach is flawed here based on my lack of understanding of the characteristics of the waveform graph and cursor manipulation. Has somebody come up with a way to achieve what I am trying to do?

This is basically the method I typically used in LabVIEW 7.1 and below as described in this old post.
Of course you could upgrade to LabVIEW 8.0 and none of this is necessary! LabVIEW 8.0 has events for "Cursor Move".
Now you only need the "cursor move" and "stop" cases. Isn't that cool!
Message Edited by altenbach on 12-12-2005 07:05 AM
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Attachments:
LV8CursorMove.png ‏6 KB

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I got a very strange Windows cursor behavior with waveform graph. Simplified VI is attached.
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It seems, i cannot explain the question in good way
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Hi all,
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Solved!
Go to Solution.
Attachments:
SubPanel.lvlib ‏2 KB

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Ray.R wrote:
which route?
the bottom one is going to give you the wrong value which is what he had as a problem..
OR
you probably mean something similar to what I posted, but got the reference from within the Event Structure... Yeah, I also prefer that one
The latter, it ties the event direct to the control triggering the event, and you could use it for several boolean controls.
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Well ... the problem for me... was, for example, in the VI I posted....
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Message Edited by MJBrehm on 06-30-2006 02:21 PM

Continously and waveform graph

Hi!
In my program Im recieving sampled data from hardware
via COM port.
If I want to display the data (voltage values) in
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Refresh cursor value in a waveform graph

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Attachments:
LabviewPNRF_Reader.vi ‏77 KB

I have simplified your vi just slightly. You dont need two while loops, two event structures, event structure timeout, sequence structure (read up on data flow using error terminals). I dont have access to the file you are reading so I have disabled that section with a simulated waveform.
As you can see the cleanup has messed up your comments etc. sorry about that.
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LabviewPNRF_Reader[1].vi ‏111 KB

How do I get an event-based response to a graph cursor change?

I want to respond to the user moving a cursor on a data (X-Y) graph. (LV 7.0)
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If I use the MOUSE MOVE event to trigger obtaining the cursor values, it does not give me an event, until the cursor has stopped moving, the button is up, and the mouse moves off the cursor line.
Sure, I could use a TIMEOUT event, and read it every 100 mSec, but I don't like the time lag.
What I did was to set a flag TRUE on Graph.MouseDown and FALSE on Graph.MouseUp. I then choose an event timeout of 10 mSec or -1, depending on that flag.
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Culverson.com
Blog for (mostly LabVIEW) programmers: Tips And Tricks

No, unfortunately there is not.
To code around this limitation, I typically use the timeout event in a more complex way as follows:
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I add two special event cases:
(1) "graph-mouse down" puts a small number (e.g. 10ms) in the right timeout shift register
(2) "graph-mouse up" puts again a -1 in the right timeout shift register
(x) All other event cases (incl. timeout) wire the current timeout straight across to the right shift register.
The timeout event contains the logic to read the graph cursors and associated actions.
This way there is normally infinite timeout. Once the mouse goes down on the graph, the timeout executes at relatively rapid succession until the mouse is raised again. At which point everything quiets down.
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Run-Time Menu and Event Structure~~HELP~~

Hi, brothers,
I'm new user for LabVIEW. Use the version of LabVIEW is 8.6
One problem describe as below:
Can Run-Time Menu and Event Structure exist simultaneously?
Without Event Structure, Run-Time Menu works well, but Run-Time Menu works abnormally.after adding Event Structure,
How do I modify the problem?
Thank you for your help.
Attached is the program.
Attachments:
PC_Adjustment.zip ‏44 KB

Yes they can coexist, but not how you did it.
Every iteration of the while loop you wait for an event in the event structure, and you look if the user has selected anything from the menu.
To get this working you should add an event for <this VI>\Menu Selection (User):
Ton
PS you should add a stop button, the only way you can stop the VI is hitting the 'emergency stop' button, with hardware connected (like you have) this is not the adviced routine
Message Edited by TonP on 09-26-2008 07:34 AM
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Front panel locks with event structure loop and another while loop

Hi,
Why is the front panel locking after changing the value of the "boolean switch" twice? This problem disappears if I uncheck the "lock front panel" option in the event case. However I don't understand why that is the case since the event structure loop has already finished executing.
thanks

Do you really want the event handling to stop after detecting the first event? If so then as Christian says the event structure will cause the front panel to lock. What you can do is dynamically register and unregister the events. You right click on the event structure and enable "Show Dynamic Event Terminals" Then you can programatically register and unregister events.
Here is your vi modified to do that.
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=====================
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Attachments:
event structure test.vi ‏13 KB

Event structure and waveform graph cursor

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