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



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The Engineers' Choice Awards highlight some of the best new control, instrumentation and automation products as chosen by Control Engineering subscribers.
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The System Integrator Giants program lists the top 100 system integrators among companies listed in CFE Media's Global System Integrator Database.
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The Engineers' Choice Awards highlight some of the best new control, instrumentation and automation products as chosen by Control Engineering subscribers.
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The System Integrator Giants program lists the top 100 system integrators among companies listed in CFE Media's Global System Integrator Database.
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Each year, a panel of Control Engineering and Plant Engineering editors and industry expert judges select the System Integrator of the Year Award winners in three categories.
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This eGuide illustrates solutions, applications and benefits of machine vision systems.
Wireless Reliability in Harsh Environments
Learn how to increase device reliability in harsh environments and decrease unplanned system downtime.
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This eGuide contains a series of articles and videos that considers theoretical and practical; immediate needs and a look into the future.
July 2018
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June 2018
Discrete and process sensor fundamentals, autotuning controls, system integrator roundtable
May 2018
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Edge Computing
This article collection contains several articles on how today's technologies heap benefits onto an edge-computing architecture such as faster computing, better networking, more memory, smarter analytics, cloud-based intelligence, and lower costs.
Data Center Design
Data centers, data closets, edge and cloud computing, co-location facilities, and similar topics are among the fastest-changing in the industry.
PLCs
Programmable logic controllers (PLCs) represent the logic (decision) part of the control loop of sense, decide, and actuate. Featured articles in this digital report compare PLCs and programmable automation controllers (PACs), industrial PCs, and robotic controllers.
SIDB

Find and connect with the most suitable service provider for your unique application. Start searching the Global System Integrator Database Now!

August 2018
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June 2018
Machine learning, produced water benefits, progressive cavity pumps
April 2018
ROVs, rigs, and the real time; wellsite valve manifolds; AI on a chip; analytics use for pipelines
John O. Ayuk, PE, CFSE, PMP, CAP
Automation Engineer; Wood Group
Doug Baker
System Integrator; Cross Integrated Systems Group
Jose S. Vasquez, Jr.
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Fire & Life Safety Engineer; Technip USA Inc.
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This course focuses on climate analysis, appropriateness of cooling system selection, and combining cooling systems.
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This course will help identify and reveal electrical hazards and identify the solutions to implementing and maintaining a safe work environment.
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This course explains how maintaining power and communication systems through emergency power-generation systems is critical.
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