Using the SISO Design Tool and the LTI Viewer

Editing Constraints

To edit an existing constraint, left-click on the constraint itself to select it. Two black squares appear on the constraint when it is selected. In general, there are two ways to adjust a constraint:

• Click on the constraint and drag it. Generally, this does not change the shape of the constraint. That is, the adjustment is strictly a translation of the constraint.
• Grab a black square and drag it. In this case, you can rotate, expand, and/or contract the constraint.

For example, in Bode diagrams you can move an upper gain limit by clicking on it and moving it anywhere in the plot region. As long as you haven't grabbed a black square, the length and slope of the gain limit will not change as you move the line. On the other hand, you can change the slope of the upper gain limit by grabbing one of the black squares and rotating the line. In all cases, the Status panel at the bottom of the SISO Design Tool displays the constraint values as they change.

This figure shows the process of editing an upper gain limit in the open-loop Bode diagram.

An alternative way to adjust a constraint is to select Design Constraints and then Edit from the right-click menu. The Edit Constraints window opens.

For information on using the Edit Constraints window, see Edit Constraint(s) Dialog.

Example: Adding a Closed-Loop Peak Gain Constraint

Edit Constraint(s) Dialog

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