Derive the expression for offset in a Proportional Integral (PI) controller for regulator mode of operation (Refer Fig. 1). Consider first order transfer functions for Process (GP) and Disturbance (GD). r igure 1: Llosed alagram Let GC=3,GP=2/(2s+1)(5s+1). A step change of magnitude 2 is made in the set point R. Determine the steady state offset of the closed loop response Y for block diagram shown in (a) Fig.1 and (b) Fig. 2. Figure 2: Modified closed loop block diagram