How to make a while loop stop after "x" number of iterations?

[Coop650]

I am a new labVIEW user. I am currently using labVIEW Student Edition 2009. One practice problem I have says:

"Modify the general while loop so that it stops when the stop button is pushed OR when the while loop reaches a certain number of iterations specified in the front panel.

Test you VI with number of iterations = 10 "

I made a VI that stops after 10 iterations, but I used "Elapsed Time" and then a certain millisecond delay to get 10 loops. So anytime the number of iterations changed I woul dhave to refigure the delay. There has to be a better/easier way to do this?

Thanks for any help.

[altenbach]

In the old days, you would watch for the iteration count and stop if it exceeds a certain value.

Nowadays, simply use a FOR loop and show the conditional terminal to stop early if needed.

[elset191]

Read the help on the while loop.  Specifically, the part about the i terminal

[Coop650]

I would just use a For loop but the problem says modify a while loop so I was trying to figure it out. Its eemed easy until I started trying it haha.

Thanks for the help though.

[Coop650]

I did see that about the i terminal (I used context help inside labVIEW). I can get it to display the number of iterations but I have not been able to make it stop after just 10. I spent way too much time on this, I have to be doing something dumb. 

[altenbach · Accepted solution]

try this?

 

Remember that the iteration starts counting with zero, so you might need some adjustments, depending on how you are counting it.

[elset191]

If i is greater than or equal to required iterations, stop the loop.  You may need to increment i first since it starts at 0

Yeah, what altenbach said.

[Coop650]

Thanks guys. I was just working on this and came up with this one and it seems to work. I really appreciate the time you all took to respond. 

[elset191]

Remember i starts at 0.  Your code runs one extra time.  When your "actual iterations" indicator says 10, it's really 11.  Take a closer look at altenbach's code.

[altenbach]

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@Coop650 wrote:

Thanks guys. I was just working on this and came up with this one and it seems to work. I really appreciate the time you all took to respond. 

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Never ever do an equal comparison involving orange numerics (DBL in this case). Your desired iteration control needs to be an integer (right-click..representation..I32).

You should also do a "greater or equal" comparison for sanity. What if the desired iteration is set to -5, the loop would never stop in your code.