Am trying to do a PID control for extractors with the S7-300 using FB41 but having some difficulties with it to assign the parameters
[email protected]

 

As you have discovered, the "standard" PID controller is not quite "standard". The S7 controller, FB41 algorithm uses the following conventions:

Controller Gain units are % per % Integral action units are seconds/repeat * 1000 Derivative units are seconds * 1000

Also, the FB41 algorithm uses a "Time Lag of the Derivative Action". If you are using derivative, I would recommend setting the TM_LAG to 1/10th of the value of the derivative parameter.

To select parameters, I suggest that you take a look at tuning software, such as ExperTune. See http://www.expertune.com/advanced.html This has built-in knowledge of 500+ industrial control algorithms, and will help you to select appropriate tuning parameters based on a simple process bump test.