Fig. E7.12 presents the response of a system to a unit step in the input. (a) Use

Question:

Fig. E7.12 presents the response of a system to a unit step in the input.

(a) Use these data to derive an FOPTD model of this system.
(b) Plot the response of the model and compare with the data.
(c) The FOPTDmodel does not capture all the features of the original response. What is the feature that the FOPTD model fails to capture? What causes this dynamic behavior?

2.5 1.5 0.5 -0.5 10 15 20 25 t (s) Figure E7.12 2.