Process control tuning methods?

which of these method are better. Ziegler, Cohen-Cood and Lambda methodProcess control tuning methods?
None.





1. All of these methods are based on first-order plant models


2. They do not take into account the gain introduced by transmitters and control valves.


3. They require tests that are not always possible to carry out.





There is no such a thing as ';best'; response. It can be either fast and somewhat oscillatory, or slow and dampened.





If empirical tuning (i.e., increase gain until the system starts oscillating and divide by two, repeat with reset and rate) does not provide good results, you will need to build a mathematical model of the system. This is not straightforward and outside expertise will have to be brought. See the link.