LabVIEW
I am using two while loops in labview .. i want a single stop button to stop the both things
@mahadev wrote:
I did not get u s, can u expalin it
I am using 2 stop buttons to stop 2 while loops but i wanted to stop both while loops by using a single stop button.
thanks
mahadev
Hey Mahadev.
As you'll probably now understand, variables from outside of loops become unaccessable whilst the loop is running. You have to imagine that While Loops are pretty much oblivious to the occurences outside of them whilst they're running; but there is a way to get around this problem by making use of a Local Variable.
A Local Variable is essentially a pointer to a location in memory where a variable is stored. This way, loops have direct access to the value rather than simply being passed to it in data flow. The value of the variable can still be read and changed without having to rely on the temporarily
inaccessable dataflow link from outside of the iterating loop.
Below, you'll see use of a stop button and a Local Variable pointing to the stop loop in order to control the condition of two concurrent while loops:
You can create local variables by right clicking on the control and selecting Create > Local Variable.
Hope this helps.
BhalT wrote:Finally is this a simple problem that I am, maybe making too complicated ?
Ravens already explaind the dataflow problem. (You should really start a new thread, because your question has nothing to do with the earlier discussion here. This tread is about stopping two while loops while your question has two events structures in a single while loop)
Yes, use a single event structure as follows.
Since the loop stops no matter what, you don't even need the while loop.
You can make it even simpler if you want events for all four buttons. try it.
You should use "latch when relesed" mechanical action. Switch until released will give you two events, another one when the button is pressed, but at that time the VI has already completed. This is not what you want.
After you correct that, your code is pretty pointless, because the output is always "not equal zero", else the event would not have been fired to begin with. It would work exactly the same without the while loop present. Right?
Why are you using continuous mode? Still, running continuously, all buttons seems to work just fine. What do you mean by "...do not generate any results"? What "results" do you expect?
BhalT wrote:I was using the while loop earlier because w/o it, the vi would lock up (i.e. not respond to a second press of the same or button).
Well, the second press would generate the same output, so you would not see a difference anyway. Typically "locked up" means the VI becomes unresponsive. What exactly did you observe?
All these select nodes make the code complicated and potentially buggy because it is difficult to tell if one of the diagram constants has been changed accidentally. Too many points where bugs can hide! Here is a better and more scalable solution. Now you can easily add more buttons with virtually no significant changes in the code.
I assume that this is a dialog style subVI to be used in a larger program, even though you have not assigned any connector terminals yet. 😉
Also remember that the "run continuously" mode is a debugging tool and has no use for regular execution.
