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Display jump vs ladder update


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Hello Everyone,

I have been using Unitronics products for nearly a decade now and have very few gripes. I love how the team actually listens and reacts to their customers needs.

With that said, there is one thing that drives me nuts! It's the interaction between using a key value to jump from display A to display B, and having that same key value perform a (ladder) function while display B is displaying.

I've attached attached a few images to illustrate what I'm talking about.

I have main menu (display A) that uses SB41 (key 1) to jump to display B

I have reset menu (display B ) that gives the operator the ability to reset the count by pressing any one of the buttons preceeding the lane.

I have the ladder function that states, On rise of SB41 (key 1), While SI252 (current display) = #49 HMI info display number for reset menu (display B ), Reset Lane 1 count (ML1)

So when I run my program, the act of pressing SB41 while displaying display A to move to display B, actually resets my count in display B. I've also tried using the same code but moving my ladder to a new subroutine and linking it to the "While Displaying" and I still get the same result.

It appears the PLC processes the jump condition first, then perfoms the ladder scan. Is there any reason why it is done in this order?

Wouldn't it make more sense to reverse this and perform a display jump condition at the end of the ladder scan, so that the rising edge of buttons that are used to perform the jump don't interact with any ladder funtions that are supposed to occur after the jump has completed?

Thanks,

post-240-096494200 1331069097_thumb.jpg

post-240-023218500 1331069120_thumb.jpg

post-240-023834600 1331069129_thumb.jpg

Edited by Simon
Removed auto Smileys :-)
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Positive transition is active one full scan. In your case reorder will not fix the problem.

Going to subroutine under display is an important step in right direction!

What you need ot do is:

If you use normal Vision controller, when you want ot reset the counter in display B, put in the net, after positive transition contact of SB41 N.C. contact of SB33. this system bit is active the first scan when you enter in a display. As result, when you use SB41 to jump to new display, positive transition contact will not work in the first scan. You will need to release the buton and then to press it again to perform Reset. This is exactly what you need.

If you use enhanced model, in On Load sub of display B, activate a bit (normal coil of MB or XB, connected direct to left rail).

Use N.C. contact of this bit as additional condition, after positive transition of SB41 to reset the counter.

At the end of "While displayiying" sub - for sure after the net where you reset the counter (!) you wil RESET this bit.

Please try and let me know the result!

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Hi Emil,

Thank's for the help. I'm transitioning the code from a V120 (standard) to a V130 (enhanced). Seems like an awful lot of code to develop two subroutines and a blocking condition just so I can reset a bit using a button on the key pad. But overall this does seem to work.

I wish the R&D or software department would look into if there was a way to not have a display transition bit go high for the first ladder scan if being used for a transition. Or even more simply, continue to use SI252 for the enhanced models and just update it's value after the first scan. That would make upgrading from standard PLC's to enhanced PLC's a simple an HMI exercise!

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