how to stop a while loop with long delay

[tatuan]

Hi everyone,

I am building a simple program for turning on and off a single Bit.  The task is to turn ON the Bit for a period length T1, and OFF the Bit for a period length T2. T1 is normally different from T2, and can be controlled  by users. 

Since T1 and T2 can be variable, they sometimes can be very long.

If I use a Wait function inside a While loop, it needs long delay to be able to Stop the Main program.

 
The same situation happens when I use Timed loop.

Can anyone suggest me how to do this task?

Thanks a lot. 

Message Edited by tatuan on 04-12-2010 12:56 AM

[Yamaeda]

It's a well known problem that long delays causes sluggish response.

One easy solution is to split the delays into smaller parts, e.g. X*100ms + rest. Then either check time elapsed each loop, or calculate/make a "wait time array" and feed the wait loop.

The array is easily done through a Quotient/Remainder calculation with 100(ms) as divider -> Initialize array with 100 ms * Quotient -> Build array with Remainder.

/Y

[jcarmody]

I like using the Elapsed Time Express VI for this.  I used the OpenG Boolean Trigger VI to detect the transition between T1 and T2.

[aeastet]

I would not put a wait step. I would keep up witht he time as we go in this situation. See the example below.

[TCPlomp]

Here's another possibility using OpenG Wait ms:

Ton