Good control requires obedient valves February 2005, Michael Brown Control Engineering, Valves, Actuators & Pump Control A feedback controller effectively calculates the amount of product that is required to be fed into the process. If, for example, the output (process demand - PD) of the controller is sitting at 50%, the ...
Read more...Poor control performance is a worldwide phenomenon December 2004, Michael Brown Control Engineering, System Integration & Control Systems Design Based on my experience in every one of the several hundred plants where I have performed optimisation, less than 5% of all loops in automatic operate at all effectively. ...
Read more...Are smart positioners the answer to all valve problems? October 2004, Michael Brown Control Engineering, Valves, Actuators & Pump Control Over the many years that I have been writing these articles in the Case Histories series, the one theme that re-occurs very frequently is problems encountered with valves. In recent years I have been ...
Read more...Problems in the control of steel reheat furnaces May 2004, Michael Brown Control Engineering, Valves, Actuators & Pump Control A few months ago I was commissioned to optimise the controls of two large reheat furnaces in a steel manufacturing plant. The client was aware that furnaces were consuming gas at a rate that was very ...
Read more...Cutting losses by improving the performance of base layer controls March 2004, Michael Brown Control Engineering, System Integration & Control Systems Design This article was recently published in a leading magazine serving the pulp and paper industry - however, I think many of the regular readers of my articles will find it interesting. Few people are aware ...
Read more...Mould level control in continuous casting machines January 2004, Michael Brown Control Engineering, Level Measurement & Control One of the more difficult types of processes that I have been asked to optimise, is the level control of the mould in a continuous casting machine found in large steel manufacturing plants. A basic diagram ...
Read more...Hope for the teaching of practical control September 2003, Michael Brown Control Engineering, Training & Education In many of my previous articles I have highlighted the fact that the vast majority of control practitioners have no real understanding of the practical aspects of regulatory control. They have found that ...
Read more...Tricky pressure control in a distillation column July 2003, Michael Brown Control Engineering, System Integration & Control Systems Design Pressure has a major effect on the separation and cut in a distillation column, and column stability can be dramatically hampered if there is poor pressure control. One of the most common ways of controlling ...
Read more...The amazing problem-free plant June 2003, Michael Brown Control Engineering, System Integration & Control Systems Design
Just before starting on this piece, I read a fascinating article by a valve manufacturer in the April issue of SA Instrumentation & Control, which mentioned a case where a relatively small 1,4% improvement ...
Read more...Flow loops behaving badly: case history 70 April 2003, Michael Brown Control Engineering, System Integration & Control Systems Design I have lost count of the number of times I have been told that flow loops are very simple things, that they are easy to tune, that you do not need a tuning package to tune them, that they can be tuned ...
Read more...Filters - the great deceivers March 2003, Michael Brown Control Engineering, System Integration & Control Systems Design Noise on the PV signal was discussed in the previous loop signature article, and it was mentioned that it is generally better to live with the noise rather than filtering it out; provided it does not ...
Read more...Some unusual integrating processes February 2003, Michael Brown Control Engineering, System Integration & Control Systems Design As mentioned in previous articles, all industrial processes fall into one of two classes of dynamics, known as self-regulating and integrating. In particular refer to Loop Signature No. 2 for a full description ...
Read more...Control loop case history 68: control mayhem on a mine December 2002, Michael Brown Control Engineering, System Integration & Control Systems Design I have often written about the dearth of understanding of practical control, which is largely due to the generally purely theoretical teaching of process control at educational institutions. I have also ...
