Question: Consider the three-tank mixing process in Example with the same three 5-minute time constants and with a transportation delay of 4.3 min between the mixing point and the entrance to the first tank.

(a) Calculate initial tuning parameters using the Bode stability method and the Ziegler-Nichols correlations.

(b) Explain the changes in the tuning constant values from those.

(c) Would you expect the control performance for the system with transportation delay to be better or worse than the system without transportation delay?

Example: One of the example processes analyzed several times in Part III is the three-tank mixing process This process is selected for its simplicity, which enables us to determine many characteristics of the feedback system, although it is complex enough to exhibit realistic behavior. The process design and model are introduced here; the linearized model is derived; and the selection of variables is discussed.