Specifications

Design Controller Using the Design Tool
3-41
Similarly, start with a single scenario identical to CSTR Disturbance 1 Scenario, except
that its Controller setting should be Unconstrained. Name this scenario None.
Right-click None in the tree and select Copy. Rename the copy Hard, and change
its Controller setting to Yhard. Make another copy, naming it Soft and changing its
Controller setting to Ysoft. Your tree should be as shown below.
Select your Yhard controller. On the Constraints tab, set the maximum for C
A
to 3 as
shown below.
Click the Constraint Softening button to open the dialog box in Constraint Softening
Dialog Box. The Input constraints section shows the bounds on the inputs and their
rates, and relaxation bands, which let you soften these constraints. By default, input
constraints are hard, meaning that the controller tries to prevent any violation.