In this post, I would like to focus on how to lock-in the value generated from improving your controller performance. This is another big issue that not many people know about or understand that well. I like to think of it as the “improvement half-life” concept.
The concept is that process control optimization work delivers good payback in a relatively short period of time.
However, the performance of the controllers, and the value they deliver start to decrease over time.
This is why it’s called a “half-life”: the time taken for something to reduce to half its value. For process control optimization work, a typical half-life is only around 6 months! This figure is based on our own experience and my discussions with others working in this field.
There are a number of factors that cause this erosion of value over time. Different feed material, equipment wear, personnel changes, a change in operating philosophies, and plant modifications are just some of the possible causes of this. The tricky part is how do you manage it!?
In our experience, the best way to manage the half-life problem is to periodically review your controller performance and made any adjustments required to keep them operating at their best. It’s the “you can only manage what you measure” approach.
So how do you manage controller performance? How can you tell if the control is good, bad or downright ugly?
I’ll talk about that in my next post.