The linear systems are logged in a structure with time and values fields.
LinearReactor
LinearReactor =
struct with fields:
time: [3x1 double]
values: [1x1x3x1 ss]
blockName: 'scdcstr/Bode Plot'
The values field stores the linear systems as an array of LTI state-space systems (see
Arrays of LTI Models) in Control System Toolbox documentation for more information).
You can retrieve the individual systems by indexing into the values field.
P1 = LinearReactor.values(:,:,1);
P2 = LinearReactor.values(:,:,2);
P3 = LinearReactor.values(:,:,3);
The Bode plot of the linear system at time 27 sec, when the reactor transitions from low
to high residual concentration, indicates that the system could be unstable. Displaying the
linear systems in pole-zero format confirms this:
zpk(P1)
zpk(P2)
zpk(P3)
ans =
From input "Coolant Temp" to output "CSTR/2":
-0.1028
(s^2 + 2.215s + 2.415)
Continuous-time zero/pole/gain model.
ans =
From input "Coolant Temp" to output "CSTR/2":
Plotting Linear System Characteristics of a Chemical Reactor