This board is for PLC Related Q&A ONLY. Please DON'T use it for advertising, etc.  
Your Personal PLC Tutor Site - Interactive Q & A

"PLC for PID regulation?"

New Here? Please read this important info!!!
Email this topic to a friend
Printer-friendly version of this topic
Archived thread - Read only 
Previous Topic | Next Topic 
Home Conferences *** LIVE PLC Q&A *** (Public)
Original message

Örjan - (2 posts) Click to check IP address of the poster Feb-01-02, 10:06 AM (EST)
"PLC for PID regulation?"
Is it possible to use a PLC for PID regulation and where can I find short information about the subject?
  Top

 Table of contents

RE: PLC for PID regulation?, Steve Bailey, Feb-01-02, (1)
RE: PLC for PID regulation?, Glenn Cheverie, Feb-01-02, (2)
RE: PLC for PID regulation?, Kevin Mahoney, Feb-11-02, (3)
RE: PLC for PID regulation?, John Kirschbaum, Feb-11-02, (4)
RE: PLC for PID regulation?, rsdoran, Feb-11-02, (5)
RE: PLC for PID regulation?, Peter Nachtwey, Feb-11-02, (6)

Lobby | Topics | Previous Topic | Next Topic
Messages in this topic

Steve Bailey Click to Email Steve Bailey - (2 posts) Click to check IP address of the poster Feb-01-02, 10:34 AM (EST)
1. "RE: PLC for PID regulation?"
If the PLC you're using has a PID function in its instruction set, then you can use it. Not all models have it.

A PLC won't do PID any better than a stand-alone controller. In many cases, the PLC won't have all of the features that a stand-alone controller has. Unless the PLC has some sort of HMI device attached, you don't have an easy way for the operator to monitor the controlled variable or change setpoints.

If you're planning a new installation or a major controls rebuild, then putting your PID controls into the PLC can make economic sense (lower hardware and wiring cost, less panel space).

Be aware that adding PID functions to the PLC can significantly increase the program scan time. Also that PID tends to use up large chunks of your PLC's memory and internal data storage capacity.

  Top

Glenn Cheverie - (5 posts) Click to check IP address of the poster Feb-01-02, 02:13 PM (EST)
2. "RE: PLC for PID regulation?"
I agree with Steve statements after you find out if your PLC can handle it your next question is do I need the full PID loop or just PI.

If its the PID I found it made life easer to get the PI set straight on the PLC defore bringing in the D.

I found a manual that helped me on these loops its writen more for ordanary foke on PID"s Its not the heavy stuff.

Controller Tuning & Control Loop Performance.
By David W. ST. Clair
published by straight-line control company
3 Bridle Brook Lane,Newark,DE 19711

  Top

Kevin Mahoney Click to Email Kevin Mahoney - (4 posts) Click to check IP address of the poster Feb-11-02, 03:08 PM (EST)
3. "RE: PLC for PID regulation?"
I think you'll be surpised by the capabilities of modern PLC's with respect to PID functions. Depending on the brand you should find full PID function control blocks. Many also have optional "PID" I/O modules that provide auto tuning. Also there are several third party PID tuning software packages (like Expertune) that can auto tune a loop running inside the PLC.
  Top

John Kirschbaum Click to Email John Kirschbaum - (4 posts) Click to check IP address of the poster Feb-11-02, 03:17 PM (EST)
4. "RE: PLC for PID regulation?"
Are you asking for information on tuning parameters for a PID?
reset, gain, etc...?
  Top

rsdoran Click to Email rsdoran - (427 posts) Click to check IP address of the poster Feb-11-02, 03:30 PM (EST)
5. "RE: PLC for PID regulation?"
This may be of some assistance, once you understand PID then look for whatever device to have the features to do what you need.

The simple answer to your simple question is YES

PID Tutorial
http://rclsgi.eng.ohio-state.edu/matlab/PID/PID.html

PID Tutorial
http://www.expertune.com/tutor.html

MORE PID:
http://www.mechatronics.me.vt.edu/book/Section3/PID.html

I have more, there is even a PID for Dummies book published. I read everything on the subject I can find, still dont know anything. There are so many variables involved in when and when not to use its frightening in a way.

  Top

Peter Nachtwey Click to Email Peter Nachtwey - (2 posts) Click to check IP address of the poster Feb-11-02, 08:13 PM (EST)
6. "RE: PLC for PID regulation?"
Good sites. Thanks. The .edu ones are excellent and were forwarded to others.

>I read everything on the subject I can find, still dont know anything.

Read the material many times. Simulate a system with a spread sheet. If you understand these then you are ahead of most everyone else. Somethings I must read at least 10 times , without falling asleep, before for I really know it.

  Top


Remove

Lobby | Topics | Previous Topic | Next Topic
Rate this topic (1=skip it, 10=must read)? [ 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 ]
Your Personal PLC Tutor Site Learn Now!!.