Boolean controls don't respond to input when inside an event in the event structure 
Author Message
 Boolean controls don't respond to input when inside an event in the event structure

I am using an event structure inside of a while loop in LV 6.1 and the
events are occurring the way that I want them to. The problem that I
am having is that when executing inside a specific event, the entire
front panel does not respond until the event is completed and exited
(i.e. I click on stuff and nothing happens) I've added lots of pauses
to give the cpu time to respond, but it doesn't help. I've changed
mechanical actions, I've changed events, event sources, etc but
nothing seems to help.

It seems like the event structure is designed to operate this way,
which is weird. I've even managed to crash labview by clicking too
many front panel controls while it is in an event.

Has anybody else noticed this problem? Is this a bug in the event
structure? Or am I just doing something fundamentally wrong with the
event structures?

Thanks,
Eric



Sun, 19 Dec 2004 03:08:39 GMT  
 Boolean controls don't respond to input when inside an event in the event structure
I am afraid that is the intended behavior.  Events lock the front until
processed.  If you need to get around that you can look at an example of
using queues in event structures at www.openg.org

Mike Sachs
Intelligent Systems


Quote:
> I am using an event structure inside of a while loop in LV 6.1 and the
> events are occurring the way that I want them to. The problem that I
> am having is that when executing inside a specific event, the entire
> front panel does not respond until the event is completed and exited
> (i.e. I click on stuff and nothing happens) I've added lots of pauses
> to give the cpu time to respond, but it doesn't help. I've changed
> mechanical actions, I've changed events, event sources, etc but
> nothing seems to help.

> It seems like the event structure is designed to operate this way,
> which is weird. I've even managed to crash Labview by clicking too
> many front panel controls while it is in an event.

> Has anybody else noticed this problem? Is this a bug in the event
> structure? Or am I just doing something fundamentally wrong with the
> event structures?

> Thanks,
> Eric



Sun, 19 Dec 2004 03:24:39 GMT  
 Boolean controls don't respond to input when inside an event in the event structure
Any code that is inside a specific event has to complete before
LabVIEW will handle any additional events.

If you submit your code, we can give you a more definite answer to
your question.



Sun, 19 Dec 2004 03:37:59 GMT  
 Boolean controls don't respond to input when inside an event in the event structure

Quote:
> I am afraid that is the intended behavior.  Events lock the front until
> processed.  If you need to get around that you can look at an example of
> using queues in event structures at www.openg.org

The panel is locked to avoid race conditions between what your diagram
is trying to accomplish and what the user might be doing.  If you are
going to gray or show/hide a control, you do not want the user's actions
to be interpretted until your diagram finishes responding to the
original event.

If you are familiar with how computer interrupts are handled, it is very
similar.  However, if your diagram isn't doing anything that is in
conflict with the user's actions, you can turn off the panel locking for
an event when in the configuration page for the event.

You probably also want to look at the event examples in
examples/general/uievents.llb, and at the ones posted previously.

Greg McKaskle



Sun, 19 Dec 2004 12:05:13 GMT  
 Boolean controls don't respond to input when inside an event in the event structure
I ran across this problem before with stopping a loop inside of an
event.   Try to right click on the title bar of your event and slide
down to unselect  "Lock Panel until Handler Completes".

Jeremy



Sun, 19 Dec 2004 23:32:18 GMT  
 Boolean controls don't respond to input when inside an event in the event structure
Thanks for the help. I unlocked the panel for several events which
allows for the user to exit the while loop. Also it seems that in
doing it this way, Labview uses its own FIFO queue to handle the
events one at a time. It works just like I need it to and I think I'm
going to try it this way. I just wonder what possible dangers are
presented in doing it like this.

Thanks again for your help.
Eric



Mon, 20 Dec 2004 00:51:52 GMT  
 
 [ 6 post ] 

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