Michael Brown Control Engineering

Email: michael.brown@mweb.co.za
www: www.controlloop.co.za
more information about Michael Brown Control Engineering

Loop signature 23: Tuning part 1.
June 2024, Editor's Choice

This is the first of several articles dealing with the subject of tuning. I have found that many people think that optimisation consists solely of tuning. I would stress once again that tuning is the last thing one should do when optimising regulatory controls.
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Loop signature 22: How cyclical disturbances affect a control loop
April 2024, Editor's Choice

When tuning noisy loops, we recommend in our courses that one should eliminate the noise by editing it out, so the tuning will be done only on the true process response, free of any noise. The controller is controlling the process, and is not controlling the noise.
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Case History 191: The weakest link.
March 2024, Valves, Actuators & Pump Control

Which is the weakest link in a control loop? The answer, without any doubt is that, in most cases, the final control element is the weakest link.
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Reminiscences of a life in control
February 2024, SAIMC

Reminiscences from Michael Brown on a long and rich journey in the world of automation together with SAIMC.
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Loop signatures 21: You cannot control if your measurement is incorrect.
January 2024, Editor's Choice

The first law of process control could be stated as saying that you cannot control if your measurement is incorrect. We all know this law. However do we all remember it in the heat of the moment?
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Case History 190: Measurement problem ruins level control.
November 2023, Editor's Choice, Fieldbus & Industrial Networking

The widely held belief in many plants that tuning will solve all base layer control problems is completely fallacious. Bad tuning is generally not the main reason for loops to perform badly. It is important when performing optimisation that all elements in a loop are considered, in addition to the control strategy, before even thinking of tuning.
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Loop signatures 20: The great deceivers.
October 2023, Editor's Choice

It is generally better to live with noise rather than filtering it out, provided it does not cause the final control element to jump around excessively.
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Case history 189: Poor furnace temperature control.
September 2023, Editor's Choice, PLCs, DCSs & Controllers

Many process engineers do not appreciate the importance of flow loops in their unit controls. A senior process engineer once told me that flow loops need not be tuned well, as they generally have little effect on the more important and much slower loops like temperatures and pressures.
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Loop signatures 19: Noise – nuisance or enemy?
August 2023, Editor's Choice, Fieldbus & Industrial Networking

This Loop Signature series of articles would not be complete without sections on the problems of noise and filtering, which are two of the most misunderstood areas in process control.
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Case History 188: Process gain – an important dynamic.
July 2023, Editor's Choice

When analysing a control loop, one of the important things that one must do is to determine the dynamics of the process.
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Digital controllers: Part 9 - Integral or reset windup
June 2023, Editor's Choice

The integral or I term in a controller is a brilliant thing. It is an extremely elegant and simple solution for eliminating offset in control. However, like everything else in this world, virtually everything good has its bad side as well.
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Case History 192: Drum pressure cycling.
May 2024, Editor's Choice

I was asked to investigate a problem of a drum pressure control that was cycling badly in a distillation column in a petrochemical refinery. The control team had spent a lot of time trying to stop the cycle by playing with the controller tuning. All to no avail.
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