9.2. The Equivalent Feedback Form to IMC

In this section we derive the standard feedback equivalence to IMC by using block- diagram manipulation. Begin with the IMC structure shown in Figure 9-1; the point of comparison between the model and process output can be moved as shown in Figure 9-2.

Figure 9-1. IMC structure.

Figure 9-2. Cosmetic change in IMC structure.

Figure 9-2 can be rearranged to the form of Figure 9-3.

Figure 9-3. Rearrangement of IMC structure.

The arrangement shown inside the dotted line of Figure 9-3 is shown in Figure 9-4.

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