Building a Cycle Timer

tgirard · Dec 3, 2004

I'm having a hard time designing a ladder logic program that cycles between two times for on / off of an output. I use a Triangle Research PLC. I can get the on State with no problem. It's the off state / Loop back that I can't seem to make work.

So, The goal here is to Turn on a pump for 5 mins then shut it off for 10 mins. I need to do this constantly.

Any help here would be greatly appreciated.

-Tim

Rube · Dec 3, 2004

Try this in your logic.

Timer #2 NOT Done
----[/]-------------------[Timer #1]--------

Timer #1 Done
----[ ]-------------------[Timer #2]--------

Set Timer #1 for 5 mins, #2 for 10 mins, and use the Timer #1 Enabled (Timing) bit as permission to run your pump.

tgirard · Dec 3, 2004

I can't believe that I didn't figure that one out... DOH!
Thank you So Much.

akreel · Dec 3, 2004

Rube said:
Set Timer #1 for 5 mins, #2 for 10 mins, and use the Timer #1 Enabled (Timing) bit as permission to run your pump.

I don't think AD has a timer enabled bit, in which case you'd use the Timer 2 not done bit.

bernie_carlton · Dec 3, 2004

How about NOT(Timer 1 Done)

Rube · Dec 3, 2004

akreel said:
I don't think AD has a timer enabled bit, in which case you'd use the Timer 2 not done bit.

That would make the pump run all the time.

tgirard · Dec 3, 2004

Actually, The way he described works perfectly.

Thanks again

Ken Moore · Dec 3, 2004

Alternative method

Have one self resetting 15 minute timer.
Run pump when accumalator is greater than or equal to 10 minutes.

Edit:
Change that to greater than vs geq

Building a Cycle Timer

tgirard

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