SA Instrumentation & Control - Control Loop

Control Loop

Case History 169: Tuning a very difficult temperature control loop
November 2019, Editor's Choice
As I have mentioned in previous articles, Greg McMillan, one of the world’s top control experts, has said that he finds temperature control loops generally the worst optimised processes as most people ...

Read more...
Smart devices for Ex areas: Unbelievably simple mistakes that prevent control.
September 2019, Michael Brown Control Engineering, Editor's Choice, Motion Control & Drives
I am often astounded by finding really basic problems with controls in plants, which have operated that way for years. These problems are so basic that one can only wonder at how these controls could ...

Read more...
Case History 167: Test your analytical capabilities
July 2019, Michael Brown Control Engineering, Editor's Choice, Motion Control & Drives
Answer to the question at the end of Case History 166 (www.instrumentation.co.za/8690r) In the last Case History article, I suggested you try and see what was not so good about a level control, which ...

Read more...
Control loop question answered
June 2019, Michael Brown Control Engineering, Editor's Choice
Control loop expert Michael Brown recently received a question from reader, Hansell Williams. The question relates to applying neural network and machine learning concepts to plant automation and control. ...

Read more...
Case History 166: Feel and understanding, or lack thereof
May 2019, Michael Brown Control Engineering, Motion Control & Drives
I was present at a very interesting discussion the other day with people who are leaders in the automation and control industry. The subject was how jobs would disappear over the next decade or two as ...

Read more...
Case History 165: Interesting tests on loop problems show how much can be deduced from the results.
March 2019, Michael Brown Control Engineering, Motion Control & Drives
I have published many articles showing problems in control loops with figures showing the tests conducted to determine the problems. This time, by way of a change, I would like to suggest that readers ...

Read more...
Case History 164: More on valves that do not control properly.
January 2019, Michael Brown Control Engineering, Motion Control & Drives
I often publish articles showing valve problems. One of the reasons is that I do not think many people understand that valves are generally responsible for 75-80% of all control loop problems. When it ...

Read more...
Case History 163: Control limitations on mineral processing plants
November 2018, Michael Brown Control Engineering, Motion Control & Drives
I was recently asked to conduct a control loop audit on a mineral extraction processing plant which was fairly old and had been acquired by new owners. A new and very modern control system had been installed ...

Read more...
Case History 162: Optimising an interesting temperature control.
September 2018, Michael Brown Control Engineering, Editor's Choice
I have often written about the huge advantages of using cascade control on processes with very slow dynamics. It is particularly useful when it comes to most temperature related processes, which are normally ...

Read more...
Case History 161: Differences between PLCs and DCSs – a discussion from a practical control point of view
July 2018, Michael Brown Control Engineering, Motion Control & Drives
Eliakim Musikiti read one of my articles in SA Instrumentation and Control and emailed me to ask what the differences are between PLCs and DCSs. I started replying to him and then thought that it would ...

Read more...
Case History 160: More problems with control
May 2018, Michael Brown Control Engineering, Editor's Choice, Motion Control & Drives
In a recent assignment to sort out problems being experienced in a petrochemical refinery, I came across the following two examples:       Drum pressure misbehaving The first was with the control of an ...

Read more...
Case History 159: Bad valves again hampering control.
March 2018, Michael Brown Control Engineering, Editor's Choice
It still fascinates me that so many control problems are caused by poor operation of control valves. I have encountered and recorded hundreds of cases of such problems. What is amazing is that many plant ...

Read more...
Case History 158: Report on temperature control of an autoclave
January 2018, Michael Brown Control Engineering, Editor's Choice, Motion Control & Drives
I was recently asked to help with a client who treats a product in an autoclave and was complaining that they always got overshoot on a step setpoint change to holding temperature. The following is taken ...

Read more...
Case History 157: Positive lead integrator tuning ‘party trick’.
November 2017, Michael Brown Control Engineering, Editor's Choice
Control loop optimisation has always fascinated me. In most cases when I am called into a plant to sort out a problem, it is something that they have been trying to fix for a long time without success. ...

Read more...
      Page 1 of 7   Next >   Last >>