Stimulate your thinking: look at PID in a different way

Maybe you should turn off the automatic tuning feature for a moment and consider what's really going on in that controller.

12/15/2010


Over the last 40 or 50 years, the automation technologies that run our process plants have changed dramatically. (Or at least they should have, but there are some plants that are still a little behind.) I’ve been around long enough to have witnessed at least some of it, but there are others that have been in the front lines and participated much more directly in the evolution.

I recently heard from Chuck Maher who certainly qualifies as a veteran. His experience includes marine engineering working on oil tankers, teaching servomechanism and feedback controls theory for GE, developing plastic soft drink bottles, and a whole lot of other things.

Chuck wrote an interesting article about understanding PID control from a viewpoint that we might not think about all that often these days. (Let’s face it, the ubiquity of computers running things tends to make us forget what’s really happening. When the black box does all the work, our individual thinking skills atrophy.) He uses Bode plots as his analysis tool, which may give you a new way to puzzle through the process and suggest new tuning approaches. (Here’s a piece we did on Frequency Domain Analysis a few years back. This may help too.)

Chuck posted the article at his Website. You have to go to the navigation bar and click where it says “control corner” to get to it. You might also want to browse around the site as well. There are all sorts of interesting things.

www.embededdesignservices.net



No comments
The Engineers' Choice Awards highlight some of the best new control, instrumentation and automation products as chosen by...
Each year, a panel of Control Engineering editors and industry expert judges select the System Integrator of the Year Award winners.
Control Engineering Leaders Under 40 identifies and gives recognition to young engineers who...
Learn more about methods used to ensure that the integration between the safety system and the process control...
Adding industrial toughness and reliability to Ethernet eGuide
Technological advances like multiple-in-multiple-out (MIMO) transmitting and receiving
Big plans for small nuclear reactors: Simpler, safer control designs; Smarter manufacturing; Industrial cloud; Mobile HMI; Controls convergence
Virtualization advice: 4 ways splitting servers can help manufacturing; Efficient motion controls; Fill the brain drain; Learn from the HART Plant of the Year
Two sides to process safety: Combining human and technical factors in your program; Preparing HMI graphics for migrations; Mechatronics and safety; Engineers' Choice Awards
The Ask Control Engineering blog covers all aspects of automation, including motors, drives, sensors, motion control, machine control, and embedded systems.
Join this ongoing discussion of machine guarding topics, including solutions assessments, regulatory compliance, gap analysis...
News and comments from Control Engineering process industries editor, Peter Welander.
IMS Research, recently acquired by IHS Inc., is a leading independent supplier of market research and consultancy to the global electronics industry.
This is a blog from the trenches – written by engineers who are implementing and upgrading control systems every day across every industry.
Anthony Baker is a fictitious aggregation of experts from Callisto Integration, providing manufacturing consulting and systems integration.
Integrator Guide

Integrator Guide

Search the online Automation Integrator Guide
 

Create New Listing

Visit the System Integrators page to view past winners of Control Engineering's System Integrator of the Year Award and learn how to enter the competition. You will also find more information on system integrators and Control System Integrators Association.

Case Study Database

Case Study Database

Get more exposure for your case study by uploading it to the Control Engineering case study database, where end-users can identify relevant solutions and explore what the experts are doing to effectively implement a variety of technology and productivity related projects.

These case studies provide examples of how knowledgeable solution providers have used technology, processes and people to create effective and successful implementations in real-world situations. Case studies can be completed by filling out a simple online form where you can outline the project title, abstract, and full story in 1500 words or less; upload photos, videos and a logo.

Click here to visit the Case Study Database and upload your case study.