Bear Mountain Drive Evergreen,
CO 80439 office:
4976 Bear Mountain Drive
Evergreen, CO 80439
Process Control Education and Technology
Robert V. Bartman, Ph.D., President
solving the toughest multivariable process analysis, PID and Model-based feedback control, Feedforward control, and Online Optimization cases in our Revelations Course.
Who are we? Click here !
For insight into how ProControl’s education and software translates process behavior and economics into separable, understandable, maintainable ARC applications, please click here to read “Appreciating and Strengthening ARC (Advanced Regulatory Control)”, a paper we’ve authored on Linkedin’s Advanced Process Control Professionals’ Forum.
The paper offers a detailed ARC design on a two-product distillation tower, covering 1) yield maximization of the more valuable product; 2) handling of reflux, reboiler, and tray loading constraints; 3) fractionation optimization using updated energy and yield economics; 4) feedrate maximization recognizing throughput vs. fractionation tradeoffs; 5) control of a 2nd product quality when warranted; and 6) the interactive dynamic decoupling keeping all this stable.
This might sound ambitious for something not done for you, by a DMC vendor – but it’s the stuff your staff learns to design and implement on their own, using the standard facilities in your own DCS system.
The paper’s Addendum discusses how ProControl’s philosophy differs from DMC’s in the critical area of killing process disturbances. Ours is simply better.
As a tickler, this paper's first few paragraphs:
"If your philosophy is applying MVC (constrained multivariable control, such as DMC) everywhere, preferably bringing CV’s and MV’s by the score into one matrix, and perhaps decommissioning one-second stabilizing PID’s in favor of ten-second (or slower) MVC’s talking directly to valves, then read no further. This is for folks interested in breaking their complex process into separable pieces, each solvable by ARC (Advanced Regulatory Control, fully implementable in a DCS without vendor support), provided there’s no loss of credits for ARC vs. MVC. This is also meant for those who’ve tried ARC beyond the basic PID level, and hit implementation roadblocks.
"I’ve broken the discussion into three parts. This one lists some of the critical skills needed to embark on ARC with assurance – without throwing darts. Think of these skills (e.g., knowing whether your process understanding is adequate) as a subset of what’s needed to be a versatile Advanced Control Engineer. The second defines the spectrum of ARC controls relevant to a real-world, two-product, distillation tower. The last critiques the classical ARC elements defined for tower control, finds them wanting in some key ways, and fixes the problems. We can still call the result ARC if you like; while it’s smarter, it’s fully implementable in a DCS. ...
"If you’re daunted at the thought of a three or four-level-deep cascade – or a little unsure on the translation of process parameters into a disturbance-cancelling feedforward controller, and would certainly not use “Lead” there since you don’t trust it – or you can’t assess the tuning compromises needed if imperfect feedforward control exists in concert with a PID above – or if you’re hesitant on using Derivative, and would never use it in any event on levels or pressures – or if you’re a petrochemicals control engineer and don’t know how to optimize a two-product tower both offline and online, or how to configure a tower’s basic controls – or know when DMC’s really needed, and when not – I could go on! – then you’re not ready for ARC played at a competitive level, and you might be content with MVC as an umbrella solution. ...
"Everything in ARC – structure, PID tuning, feedforward disturbance cancellation – is based on process understanding ...
Hope that’s enough to whet your interest. If so, click here to read “Appreciating and Strengthening ARC”.
ARC’s the platform for our education and process analysis software. More on these next.
Revelations on Dynamic Process Analysis, Advanced Control, and Online Optimization
Our flagship "Open-to-all" Revelations Courses are held in our Evergreen, Colorado Teaching Center the first two weeks in May, and November. Call us at 303-670-9092 for the exact schedule. We also teach this course throughout the year on a dedicated basis to individual corporations.
Click here for student reviews of an open-to-all class taught in Evergreen to Advanced Control Engineers from BP, Celanese, Citgo, and ExxonMobil.
Click here for student reviews of an earlier open-to-all Revelations class taught to Advanced Control Engineers from BP and ConocoPhillips.
Our Revelations Course lasts 12 full days. Its 96 solid class-hours span more than two semesters of graduate-level control courses; but any other similarity with academic control education ends there. There’s not a shred of irrelevant, unusable control theory in this class; in fact there’s a money-back guarantee if we mention such stalwarts as LaPlace transforms, or z-transforms, or Nyquist diagrams, or Bode plots, or Ziegler-Nichols tuning, in other than critically-humorous terms.
This class teaches how to think like an expert Advanced Control Engineer. We give our graduates the skills and confidence to reason-out complex, money-making control schemes on their own, on any petrochemical process. We don’t ask them to swallow the litany of Cookbook procedures and Rules of Thumb which comprise other “Advanced Control” classes. We have a myriad of testimonials attesting that such Cookbook education falls flat on its face back in the plant, where many pitfalls lurk that were omitted from the book.
In contrast, we’ve developed understandable, practical explanations for all the many principles and Rules of Thumb we're normally obliged to swallow as "Givens" in our profession. In our experience, many essential building-blocks of our trade (e.g., Derivative, Lead/Lag, Nonlinear algo's, Cascades, well-reasoned PID tuning, Model-based control, plant testing, dynamic data analysis ...) are either shunned or abused, due to an absence of real understanding, and an ensuing distrust.
Our Revelations Course changes all this, and it turns on light bulbs for even very experienced Advanced Control Engineers. They contrast our training with previous "Just trust me about that" control courses in comparisons often too strong to quote here. The old plea “Please teach me to fish!” could have come from the world’s first graduate of a quickie Control Engineer course, now struggling to demonstrate self-sufficiency back in the plant.
Instilling our desired level of understanding (including every process analysis and control pitfall, and requisite countermeasures) takes time. Our Revelations Course spans a full 96 class-hours, and if it didn't already require a full two weeks away from the plant, we’d add more. In our experience, turning an "expediency crank" – shortcutting the educational process – risks making graduation of self-sufficient Advanced Control Engineers just a pretense. We spend nearly half the course, for example, on one subject: process understanding. We learn what sets the depth of dynamic knowledge needed for all facets of control, what justifies our plugging this knowledge directly into control system design and tuning, and how we can acquire the precise process parameters we need for control, despite many plant-testing and data analysis pitfalls. This process emphasis is time well-spent, since it eliminates all trial-and-error from our control world.
Some comparisons with previous industrial control education:
"I have taken 3 HW courses, and not one showed me how I could make more money with the HW system."
“I have never taken such a ‘control’ course before. DMC was just concerned with how to use the tool. This course taught us how we should think to make control schemes: now we’re prepared.”
"I took a (very well-known competitor’s) course that got me interested in process control, but didn't teach me how to do process control."
"I've taken other Fox "control issues" courses, and was taught to cycle controllers and tune for QAD - which has been absolutely of no use at work."
“This course was absolutely justified and worthwhile. This control course was MUCH more valuable than *******’s Modern Loop Tuning Class. This took a much more fundamental and practical approach to control, rather than tuning just based off of theory.”
“This course gave great insight into conditions where PID-based primaries “break down”, and where model-based controllers offer the simplest effective solution. This was an excellent explanation of something I’d seen many times in the plant, but couldn’t do anything to improve.”
“It was definitely the best course I've ever taken. It delved into the most complex issues, but it was made simple enough so I could understand them.”
“Definitely justified – the wealth of knowledge, the passing-on of experiences, and the reference materials are invaluable. I will feel much more comfortable looking for ways to make $$$ now, rather than being purely reactive. I feel a lot more experienced!”
“After courses from *******, and a 10-day workshop on DMC, this course has finally made me confident in dealing with process dynamics, PID feedback, feedforward control, and the more complex regulatory controls – the things I’ve been working with for over 5 years!”
“I learned that online process optimization opportunities can exist outside of DMC, if we properly think about a control scheme’s real objectives, and recognize that the capacity for better control often exists in the DCS itself.”
We provide considerable FREE post-course applications problem-solving and multivariable data analysis, at your request, to help you realize your maximum return on your course investment. We do this simply because we enjoy getting our hands dirty with real process data, and real process economics.
This free consulting has meant much to our graduates, and their companies.
Please call (office: 303-670-8392; cell: 303-670-9092), or e-mail email@example.com, for the fee for our 96 class-hour Revelations Courses – including our “open-to-all” classes taught in Evergreen, Colorado. We’ll be happy to send you a detailed Revelations Course Agenda, and would encourage your comparing its ‘meat’ with any other education on this planet.
ProControl’s multivariable process analysis, tuning, and control evaluation tool has all you’ll need for full ARC credit capture.
Click here for reviews of Discover by many major petrochemical corporations. Contact us for an in-depth list of Discover’s many features, and why each is important.
Here are our minimum requirements for a process analysis tool for ARC implementation:
1) “Best Fit” model parameters provided by statistics for each independent variable: Process Gain, Deadtime, at least two Lagtimes, and Leadtime (to fit overshoots and inverses). While these classical parameters suffice for the majority of petrochemical responses, additive “fit anything” vectors should also be available, complementing this classical structure.
Standard process analysis tools provide Gain, Deadtime, and one Lagtime. But these are often inadequate; feedforward cancellation outcomes, up-front PID/feedforward adequacy studies, and model-based control relieving ARC’s limitations, all benefit from modeling a more complex process with additional dynamic parameters.
2) “Worst Case” (for PID and feedforward stability) model parameters, yielding a fit just at the margin of model credibility, but with dynamics purposely skewed to cause stability problems. The murkier the process data, the further these parameters diverge from Best Fit values. Assessing this alternate Worst Case model should be intuitive, requiring no statistical knowledge – preferably just a mouse click. So what … ?
3) Easy carryover of these two models into optimal PID and feedforward tuning, then to PID and feedforward case study comparisons assessing adequacy of the current process data. A good tool should guide us to a “The data’s OK”, or “Not” decision, and if “OK”, to tuning which minimizes vulnerability without being unduly conservative – preferably, all this with the user ignorant of statistics. If “Not OK”, of course, we either look for another window of ‘opportunistic’ data, or we run a sharper plant test.
“Optimal” PID tuning yields minimal PV cycling, with no more than 20% MV overshoot. Tuning should cover an unlimited range of process dynamics, all PID algos, and all PID control intervals. Variable intervals let us view the serious degradation in constants, in PID structure itself, and in disturbance-killing capacity when we shift loops such as pressures from one-second ARC to much slower MVC frequencies (!)
4) Ditto for carryover of these two sets of model parameters into an ARC-compatible model-based controller, rather than a PID. Why? Click here, then skip to the last “Strengthening” section of Appreciating and Strengthening ARC..
5) Multivariable inputs: we’ve needed as many as five to sort things out. Here it’s essential that the analysis tool lets us know, not just as a simple percentage, but also graphically, how much each independent variable contributes to the overall response. Without such comparative graphics we may build feedforward controllers based on a “Best Fit” model for a particular MV or Load that’s total nonsense (since another variable’s much more significant in securing a good fit).
6) Use of what we’ve already learned: As a corollary to (5) , a good analysis tool allows the impact of minor contributors (in the current multivariable data) to be backed-out using historical, already- known, model parameters – not those arising from current “Best Fit” statistics.
7) Graphics: a good tool promotes comparisons by easy grouping and scale-sharing of both measured and calculated variables.
The message: good process analysis software doesn’t simply yield a multivariable model; it encourages probing this model’s adequacy for ARC.
Our process analysis and PID/model-based control/feedforward tuning and exploration tool, Discover, offers much more than this, including ability to draw continuous tray temperature-based models through discontinuous GC or Lab data, and online Help for every class of process analysis problem in our experience. Reviews are here.
Our clients enjoy quickly solving major tuning problems on their own. Click here for an unsolicited e-mail from a major overseas refinery, extolling Discover’s full-PID tower pressure control tuning, in contrast with the outcome from other well-known tuning software. See this site’s before / after graphics.
Click here for similar delight with Discover’s full-PID tuning of a troublesome FCC Fractionator drum level, whose poor control had plagued their downstream gasoline operations. Their lead control applications engineer was particularly impressed with the predictive stability afforded by our tool’s Derivative (see his graphics).
In both cases, one quick plant test did the job – then no more suffering. Our students are happy to discover that Discover gives the same great results in their plant as it did during their Revelations Course. Just need a little of that Process Understanding we talk about …!
Click here for a Stabilizer tray temperature (adjusting reboiler steam) example, here for a much more difficult Stabilizer reflux drum level (also adjusting reboiler steam!) example, and here for a tough fuel gas pressure control problem (pressure transmitter miles away from its valve) having plagued a refinery’s furnace operations for years.
Discover 21.0 now includes our Dynamic Reconciliation (DR) Model-Based Control technology. Model-based control’s replacement of a PID, in select cases, is the final “strengthening” component in our paper “Appreciating and Strengthening ARC”, accessible here. .
Click here for a separate discussion of Dynamic Reconciliation (DR)’s attributes.
Please contact us for more info on Discover. Our Revelations Course students graduate with high Discover expertise, and uniformly high praise.
Finally, our two four-day courses, Revelations on Dynamic Process Analysis and Advanced Control for Process Engineers, and Control Revelations for Instrument Technicians, are most often taught onsite. We have excellent reviews on these sessions. The Process Engineer class, as it says, emphasizes process analysis of dynamic plant data (from a Process Engineer’s perspective), and how/why Process Engineers should work with Advanced Control Engineers to optimize process operations. The Instrument Technician class puts much more emphasis on loop tuning, and on avoiding tuning’s many pitfalls. Please call for more information on either session.
Click here for a review of our Process Engineer Course, taught onsite to the Process Engineers of all U.S. refineries and chemicals plants of one of the largest worldwide petrochemicals corporations.
Click here for the motivations to train your Instrument Techs, and your Process Engineers as well, to do their jobs more effectively – and to fully appreciate the efforts of your Advanced Control staff.
Please contact ProControl (office: 303-670-8392; cell: 303-670-9092; or e-mail: firstname.lastname@example.org), with Revelations Course content or fee questions, and/or student reservations for the open-to-all session above. We’re happy to provide a wealth of comparisons with other Control Educators -- very likely from Control Engineers within your own company.
Please also contact us with questions on our Discover 21.0 software, now providing DR model-based control technology at no charge.
Best regards to all,
Robert V. Bartman, Ph.D.
President, ProControl, Inc.
Click here for more on me,
and my past career with Exxon!