Using a Simulink representation of the reactor/flash plant, add an additional feedback control loop for reactor level HR (assumed in this chapter to be perfectly controlled) by the following steps:

(a) Modify the gain matrix (Eq. 24.1) to incorporate both a new manipulated variable w3 and a new controlled variable HR. What does the RGA indicate about the pairing of controlled and manipulated variables for this situation?

(b) Use RGA recommended pairings, or any others that are appropriate, to control the plant (including HR). Can you achieve essentially the same responses as shown in Figure while controlling reactor level with a PI controller? Using P-only control of level? Explain your results and discuss whether it is important to control reactor level exactly at the setpoint.

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