September/October 2010

ISA Automation Week

Technical innovator, prolific author, teacher describe ISA Life Achievement Award winner

Gregory McMillan

By Jim Strothman

EDITOR'S NOTE: ISA continues its tradition of honoring leaders throughout the automation industry by presenting the Automation Founders Circle awards. This year's recipients are Dean Kamen with the ISA Honorary Member award, the highest honor bestowed by the Society, and Gregory McMillan with ISA's 2010 Life Achievement Award.


The 2010 winner of ISA's prestigious ISA Life Achievement Award, Gregory McMillan, credits working with "100 of the best minds in process industry" at Monsanto Co. for successfully launching his professional careers as a process control technical innovator, an educator, and a writer.

"In Monsanto's Engineering Technology (ET) department, created and inspired by James R. Fair, University of Texas Energy Chair Emeritus, I got to work with the leaders in process modeling and control," recalls McMillan. They included well-known industry giants John Berra, now chairman of Emerson Process Management; Henry Chien; Larry McCune; Bob Otto; Terry Tolliver; Vernon Trevathan; and Stan Weiner, among others.

"Being invited into that group … what I learned was incredible, from the best minds. Monsanto also just put me 'out there'-in plants, where I was given free rein, and had to figure out things on my own. Hands-on is the best way to learn in this business, no question."

McMillan also credits books by Greg Shinskey, receiver of the ISA 2008 Life Achievement Award, for helping him develop a deeper understanding of the relationship between loop performance, controller tuning, and process dynamics.

Expert in pH control

Generally acknowledged as a leading expert in pH control and modeling/simulation, among other technical areas, McMillan spent the first 33 of his more than 40-year career at Monsanto, and its spin-off Solutia Inc.

Gregory McMillan

There, he specialized in improving loop performance, controller tuning, valve dynamics, opportunity assessments, dynamic simulation, fermentor control, pH control, and reactor control. He modeled/simulated alternatives and created equations that simplified processes, reduced costs, and significantly improved process system performance time.
McMillan is often described as "an all-around good guy" who is a big believer in sharing his knowledge with less-experienced engineers and technicians by teaching, mentoring, and writing. He is a prolific writer-having authored more than 50 articles and papers, plus 18 books.

Winning the Life Achievement Award "meant more to me than I realized," McMillan said. "It's recognition for a culmination of a large body of work over a long period of time. It's recognition I've done something unique. I've also always enjoyed combining practical perspective with humor."

Award cites innovations, writings, teachings

His award citation, to be presented at ISA Automation Week 2010 beginning 5 October, in Houston, Tex., states:

"In recognition of a 40-year career of innovation in process control technology through invention, publication of articles, papers, and books, as well as teaching the application of control theory."

"I can think of no one more deserving of the Life Achievement Award than Greg McMillan," said Emerson's John Berra. "Greg is one of the foremost process control experts in the world, and I don't think there is anyone who understands loop dynamics better than Greg. His life has been all about advancing process control and improving the performance and safety of process plants."

After retiring from Monsanto/Solutia in 2001, McMillan taught at Washington University in St. Louis, where he injected the "cool factor" by developing a hands-on laboratory in a teaching environment previously limited to books and white boards.

He moved to Austin, Tex., in 2004 and started a new career as a part-time consultant at Emerson Process Management. Today, he specializes in developing modeling programs for Emerson's DeltaV DCS system.

Technical achievements

Asked which of his accomplishments he felt were among the most significant, McMillan listed several equations he created, which simplified operations and improved control performances. They include equations for:

  • Ultimate period and ultimate gain
  • Dead time from valve deadband
  • Reset time as a function of dead time and ultimate period
  • The effect of A/D noise
  • Controller gain and peak error for cascade loops
  • Attenuation of noise
  • Reset time for approach to surge curve

McMillan also developed valve dynamics and other advances in process control calculations and methodology.

"Valve dynamics and pH systems are tricky problems," McMillan said. For example, injection delays occur when trying to get reagent into vessels. "It's important to track down the sources of dead time. Injection delays can be enormous-it sometimes takes hours to flush out the dip tube and get the reagent into the vessel."

McMillan recalls being frustrated by contractors trying to save money by not putting positioners on valves, causing problems. "When you are trying to start up a plant that's costing a million dollars a day, and not paying for positioners, which cost $500 or $600, it doesn't make sense," he said.

At ISA Automation Week 2010, McMillan will present a paper titled "How to Get the Most Out of Your PID," which elaborates on yet another achievement, discovering a unification of tuning methods for controller gain, and how tuning and dynamics affect performance.

"All the most well-known tuning methods end up with basically the same equation for controller tuning when tuned for maximum disturbance rejection," he explained. "For people who have a favorite tuning method they are convinced is the only one, this might be unsettling. For me, it was extremely satisfying because (the paper) reveals an underlying fundamental law that offers insight and opportunities."

Modeling played key role

McMillan said another technology, modeling and simulation, that he has advanced throughout his career, helped him, in a major way, to achieve many of his accomplishments.

Monsanto's ET group developed FLOWTRAN, which was such an advance in the state-of-the-art of process design modeling that the U.S. government directed it to be sold to Aspen Institute. In the "old days," McMillan said, "you had to punch cards for the IBM Continuous Simulation Modeling Program (CSMP) and submit them for an overnight run in a room full of mainframe computers.

"When I got terminal server access to a computer with the Advanced Continuous Simulation Language (ACSL) program, I thought I was in heaven-even though ACSL was designed for the aerospace industry," he said. Later, he used HYSYS Plant for dynamic simulations.

An ISA Fellow, he has written several best-selling ISA books that include Good Tuning: A Pocket Guide, 2nd edition (2005), Advanced pH Measurement and Control, 3rd edition (2004), and Tuning and Control Loop Performance, 3rd edition (1994). ISA published this year his Essentials of Modern Measurements and Final Elements in the Process Industry. McMillan especially likes his humorous books-a rarity in automation and process control reading matter.

Still an educator

McMillan and Emerson colleague Terry Blevins, a principal technologist in DeltaV Product Engineering, have developed a web site,, chock full of technical writings and useful advice.

The site's "Education" section includes information from "Deminars" (McMillan's term) developed at Emerson. The first-ever Deminar focused on "PID Control of Sampled Measurements (How to Eliminate Oscillations from Analyzers and Wireless Measurements with a PID Enhancement)."

The latest two Deminars, readied for August 2010, look at "PID Control of True Integrating Processes (How to Reduce the Batch Cycle Time for Temperature and pH Loops by 25%)" and "PID Control of Runaway Processes (How to Improve the Performance of Exothermic Reactor Temperature Loops)."

Earned honors, awards

McMillan received the ISA "Kermit Fisher Environmental" Award for pH control in 1991, the same year he was elected an ISA Fellow. He received several book and magazine awards, and in 2003, he was chosen as one of InTech's 50 most influential innovators for advancing automation and control technologies.

He received a B.S. from Kansas University in 1969 in Engineering Physics and a M.S. from University of Missouri-Rolla in 1976 in Electrical Engineering (Control Theory).