Logix Designer PID instruction for CompactLogix

[jeffrey.kelvington]

Hello there! This is my first time posting a question here... on PID instruction for CompactLogix controller so I am giving it a try...

Please see attached, a screen shot of PID instruction...



Trying to understand what I need to put in for Tieback, Control Variable, PID Master Loop, Inhold Bit, Inhold Value... There is no explanation on these in Logix Designer Online Help.

I am setting up control loop to control heat plate temperature. The therm-couple is embedded in heat plate. Using discrete output to SSR to switch on 120v heaters.

Any help will be appreciated!

Jeff

 

[Ron Beaufort]

Greetings Jeff ...

and welcome to the forum ... well, you're almost there ... you've actually posted in the "Practice" area – so very few members are going to see your post ... but with luck, a friendly moderator will come along soon and move the thread into the Q&A board ...

in the meantime ...

PID is just ONE piece of a much larger puzzle ... in order to get the most accurate answers, you should post your ENTIRE project file – the one with the .ACD extension ... you'll have to zip it first – forum rule ... just attach it to your thread ... ask if you don't know how ...

once we've got the file, we can check out your input and output signals – and their scaling ... we can also check out how you're going to "trigger" the PID to execute it on a timely basis ...

and so on ... and on ... and on ... once you've clicked that little "3-dot" button on the PID you'll find that the answers to the questions that you've asked so far will only be a fraction of what you're going to need to know ...

good luck with your project ...

 

[jeffrey.kelvington]

Hi Ron! I was surprised that you eventually came across this posting and respond to it! I admire your amazing postings that I was reading recently on understanding the P and I topic dated back in stone age! (about 10 years ago...)

Ok, back to the point... I will be glad to share the ACD project file I am working on with you, but not willing to post it up on this forum so is there a way to send this off directly to you? Beware, it is grossly unfinished work but it is "work in progress" thing.

By the way, I found more info on the PID operands in Logix5000 Controllers General Instructions Reference Manual and I hope this would help me get started on setting up PID correctly.

Looking forward to hear back from you!

Jeff

 

[Ron Beaufort]

you're welcome to email it directly to me - and I will certainly treat it as confidential ... I'll be happy to take a quick look at it - BUT - right now I'm working on developing some custom training projects for several of my larger customers ... it might be several weeks before I'll have a chance to dig into your program ...

I don't mind trying - but I can't make any promises ...

good luck with it ... hopefully the book will help ...