How many while loops in an application is appropriate?

Hi,
I am writing an application that is growing and now I'm about to add the 5th while loop on the root level. So far, I have loops for:
1. Receiving data
2. Transmitting data
3. Processing commands
4. Handling front panel events
5. (about to be added) background timed events
My question is this - is there any "recommended" maximum number of while loops in the base VI or is it purely up to the application? I am wondering if it matters, or if I can simply add loops as needed. Other than combining the transmit and receive data which I don't want to do due to speed, there's not much else to combine.
Any comments?
Thanks,
Jason

Isn't LabVIEW wonderful? It is so easy to write applications that do many things seemingly at the same time in paralell.
I would not worry too much about the number of loops. Make sure that each loop is well behaved and only spins if there is really something to do. A single empty loop without any wait statement can be very taxing for the CPU and hurt responsiveness in all other loops.
As long as the UI is nicely responsive and the CPU is not pegged at 100% you're fine.
LabVIEW Champion . Do more with less code and in less time .

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DECLARE
zz NUMBER := 1;
BEGIN
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DECLARE
zz NUMBER := 1;
BEGIN
While zz < 10
LOOP
prompt Look THEO I am looping...;
zz := zz + 1;
END LOOP;
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I get the following error...
prompt Look THEO I am looping...;
ERROR at line 6:
ORA-06550: line 6, column 14:
PLS-00103: Encountered the symbol "LOOK" when expecting one of the following:
:= . ( @ % ;
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BEGIN
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END LOOP;
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Attachments:
Generate Occurrence2.vi ‏23 KB

Thank you for responding to my question. I think I understand it now. The first click of the Set Occurrence button, the lower loop gets out of the current iteration. At next iteration, even though the conditional terminal sees the True signal, it can not exit because it's waiting for the loop to finish. Only after we send the Occurrence again then the loop will finish it's task and exit. Again, thank you for your help.
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Im trying to underdstand the differences in the
different loops. I can grasp the for loop but I dont
see how a while loop works, or how it id different
from the other?
for (j = INIT; j < MAX; j++) {
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}is the same as
j = INIT;
while (j < MAX) {
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}Lee

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Hello,
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http://zone.ni.com/devzone/conceptd.nsf/webmain/b6605678ad7a09a8862568eb007a6d7a?OpenDocument
http://zone.ni.com/devzone/learningcenter.nsf/03f7c60f17aad210862567a90054a26c/1b36040af87887078625
6cbc006fe314?OpenDocument
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Attachments:
CO_Detection_Monitoring_System_Modified.vi ‏60 KB

Hello Everyone-
I've just posted a message about stopping a while loop and it was answered accurately and quickly- thanks to LV_Pro and PauloM- thanks much- its nice too see that there are many helpful people out there! Unfortunately, I have 2 more questions to ask of the forum.
My application is almost completed- I just need to add an elapsed time counter that will tell me how long it took for my LED to trigger (from my set point-i.e. when from 0:00:00 until when my loop stopped).
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Thank you again,
Daniel
Attachments:
CO_Detection_Monitoring_System_Modified.vi ‏60 KB

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tab control.vi ‏24 KB

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Ed Dickens - Certified LabVIEW Architect - DISTek Integration, Inc. - NI Certified Alliance Partner
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HI
I am quite a novice in Labview.
I have a problem in my project. I used a while loop inside my vi to build an array of ten values along with other loops. Then I used a stop button to stop manually the while loop. But it seems like the loop doesn't stop in the middle of the array building and so other loops in the vi doesn't work until the while loop finishes building the array and as soon as while loop execution is over, the complete vi stops. But all that I wanted was to build the array using the shift register along with the control to stop building array anytime. And not to stop execution of other structures when the while loop finishes.
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Rahul

Hi Rahul,
Modified ur Vi to work with single button.
But the subtract case is not in any loop.
So, once both the loops stop, the subtract case will execute only once. Depending on state of subtaract boolean at that time, corresponding case will be executed and the Vi will stop.
so think of a logic where u can put this also in a new loop.
Or you can also incorporate it in one of the two loops and pass the other loop's data to it.
Let us know how you will proceed in this regard
I am posting your VI as well a VI with my modifications VI in Labview 7.0 so that Thomas can give his suggestions too
Plus, always keep a time delay in your while loops.
Oh sorry, the "arrayinouttestnewfinal.vi" is the modified vi
Regards
Dev
Message Edited by devchander on 01-10-2006 06:15 AM
Message Edited by devchander on 01-10-2006 06:19 AM
Attachments:
arrayinouttestnewfinalnew4.vi ‏59 KB
arrayinouttestnewfinal.vi ‏63 KB

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The operator can enter data into either double or click the boolean. If distance is changed the second loop does what is required to process the change. The same happens with stepsize. If step is clicked the ±stepsize value is added to distance and the result is processed. In each case the front panel should track the result of the input and subsequent processing.
Because the clusters are outside the while loop, they are not updated unless I click 'highlight execution' which seems to allow updating each time the execution highlight is updated. There are other issues if I move the clusters into one of the loops.
I've tried referencing the clusters and using local variables and nothing works. It looks like overkill to use shared variables for this.
Any ideas would be greatly appreciated.
Thanks,
Frank

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Attachments:
Front Panel Reference.vi ‏33 KB

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Dear Sir,
how to out from infinite while loop in sub VI from main VI
attached photo for solution but I can't understand it and i can't find the function in photo
please help
Attachments:
stop_subVI_frm_main.JPG ‏36 KB

Asking how to get out of an infinite loop is like asking how to find the end of a circle. I'm not trying to be sarcastic but by definition, if there is a way out of the loop, then it is not infinite. I think what you are asking is how to avoid creating an infinite loop. Is there something about the suggestions you have been given that you do not like? My favorite suggestion is the notifier but maybe you just need an example. Turn on context help and read about the notifier functions in the code below.
This is your top level VI
And this is your subVI
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=====================
LabVIEW 2012

How many while loops in an applicatio​n is appropriat​e?

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How many while loops in an application is appropriate?