Advanced process control


Thread Starter

Arvind Sharma

I have been trying to identify process improvement opportunities in our batch plant where advanced process control can make an impact.
I am currently implementing a Controllogix solution to a Waste water treatment project. The Analog to Digital ratio is high, and there are quite a few PID loops. Most of the PIDs are for controlling the pH with a given set point.
pH is non linear and the rate of flow of waste water varies (comes in batches). This would be a good opportunity to try out some advanced control algorithms, and I have been trying to figure out an appropriate software that would interface with AB Controllogix. Our vendors suggested using RSTune or RSLoop Optimizer. RSLoop Optimizer seems to be a good fit. I was wondering if one of you Process control gurus could shed some light on appropriate software packages. Is RSLoop Optimization the best Advanced Process Control software in the market for our situation?
Should I start thinking along the lines of Adaptive controllers? What other packages should I be aware of?
This would help us out immensely.


If you are going for APC, sit and talk with your people about all the things that they want, that are likely to improve performance. Make a list of items that are required. Check for availability of readymade software's.

But the best strategy is to make the APC software inhouse due to the complexities involved.

Some notes.

Advanced Process Control is a very complex subject. Here you are talking about utilizing logic and software and probably also adding some field hardware to improve economics and/or controllability of process.

Unless there is a company which has made a software for your process, and for your size, the chances of an off the shelf product working well
is very limited. In fact almost impossible.

A lot of customization needs to be done to any standard software. People have to be trained to operate the new system properly, else you will find that the new system is generally offline and slowly termed a failure. One very popular APC installation in one of m Ex-companies is lying
unused. One of the VP's that I met some time back was lamenting on such a collosal waste of money.
And it was very difficult to convince him that a system that works for a few days, should work in the long run, perhaps with a bit of troubleshooting.

Assess what other changes are likely in your plant (capacity changes and other modifications) that may adversely affect the system that you chose and so on.

You can also look at and find APC text for Profile based controls.