Created Date: March 30,2007

Created by: franji1

Just use a RST of the output below the PONOFF IBox with whatever "disable " logic you need. Note that it will NOT remember the state, so the next time your input turns ON, it WILL TURN ON!!

Here's the basic logic of PONOFF (%P1 is parameter 1, %P2 is parameter 2, %P3 is parameter 3):

STR %P1

ANDN SP0

PD %P3

STR %P3

ANDN %P2

STRN %P3

AND %P2

ORSTR

OUT %P2

You may be better off using an "enable " contact in series with the PONOFF Output driving your REAL Pushon/off output???

Not 100% sure what you 're looking for.

Created Date: April 02,2007

Created by: mmohn

In the past, I coded flip-flop circuits using the logic you showed, but with the addition of %P4 which acts as a "reset " (to turn it off no matter what the current state) and often with some "set " logic too (to turn it on no matter what the current state):

STR %P1

ANDN SP0

PD %P3

STR %P3

ANDN %P2

STRN %P3

AND %P2

ORSTR

ANDN %P4

OUT %P2

I was writing some new code, and I think the new Iboxes look pretty slick (especially the math boxes) to clean up accumulator logic, so I thought I'd try using the other Iboxes where I could to make the code look cleaner. But I use a lot of flip-flops in my logic, and I set and reset them alot. So this push-on push-off Ibox may not be much use if I have to add a another rung to replace one contact.

Created Date: April 02,2007

Created by: franji1

We had a lot of discussions about the PONPOFF IBox, exactly about the functionality you are describing.

We thought of adding "everything ", which complicated it a little more. Do we use power flow as the enable (basically Reset if no power to IBox)? What if you want to automatically set it - do we then add a Set parameter? So if we have Set as a parameter, why do we have the Reset as power flow? Shouldn't Reset be a parameter like the Set parameter?

And on and on. We came to the conclusion, just do the basic PONOFF IBox as you see it now (quite simple indeed). If people wish to add functionality to it, they can use it and add code below the rung, or recode it from scratch.

If you notice, PONOFF is a "stand alone " output. Its functionality is NOT dependent upon power flow, because of the conclusions mentioned above.

Created Date: June 29,2007

Created by: joev

PONOFF is a great addition to the instruction set! It eliminates at least 3 lines of code per button. But... I'm doing an application right now where I would like to disable the PONOFF simply by placing code in the rung. It would be much easier, and simpler for the less code savvy to understand. I need to give it permission to be set. By the way, I'm already using RST on the next rung to shut off under certain conditions. That works OK, but it would be nice if there were simply a reset input. I would envision something that looks like a CNT instruction. If you want to inhibit the instruction, you put code in the active input. If you want to reset it, you put code in the reset input.

A couple PONOFFs make a great toggle to switch conditions such as auto/manual or a job selector on a machine running multiple jobs. This kind of toggle seems much more functional than my old hard coded flip-flops. You used to have to hold the button for a brief time to get a good toggle (probably needed a couple of scans). Now with PONOFF, the toggle operates with just the briefest touch. Yea, you might use the functionality in a screen, but I often find that too limiting if you need to give permission for something to happen from logic, or need to reset it. I prefer to use momentaries from my screen objects and hard code any latching I need. I have control of my logic from one place.