Consider a closed-loop system consisting of a first order plant with transfer function P(s), and a PI controller (k_p, k_i \neq 0; k_d=0) with an actuator that has an output range between -1 and 1, as shown in the following diagram. Furthermore, you can assume that there are no noise and disturbance inputs injected into the system, and the plant satisfies P(0)=6.

The following two plots show the signals y and r for references of the form r(t)=r_0 \mathbf{1} (t), for two different values of r_0. Match the system response plots to the possible values of reference input magnitudes r_0. (The plots are not drawn to scale.)