Main and subvi question

[VeeJay]

Hi All,

I was wondering if there is any difference between the two codes I have attached. They are simple codes, but, I would like to understand main and subvi better. I saw this type of coding in one of the examples.

Notice the second example has a 'while' loop but the STOP=TRUE. This means that it runs only once everytime. But, why should you specifically have a while loop with a STOP=TRUE? How is it different from the first one? Is it just good programming? THanks!

V

[RavensFan]

There is no point to the while loop in your 2nd jpeg.  There are subVI's that have a True wired to the stop terminal with a purpose.  They are called functional global variables or Action Engines Those have uninitialized shift registers that can store data between calls of the subVI.

[stevem181]

Also note that there is no delay in the main while loops. This will cause a high CPU usage for no good reason.

Use a "Wait(ms)" or "Wait Until Next ms Multiple" function to give the CPU time for other tasks.

steve 

[VeeJay]

Yea, I always use delay in while loops, lest my CPU would max out. I put this example up in like a minute without giving so much thought into detail I guess.