PID  CONTROLLER LABORATORY

Describes the frequency dependent amplitude gain of disturbances that are affecting the process input, e.g are added to the controller output (MV). They are often called load disturbances. To ensure that no disturbances are gained "too much" the input sensitivity function upper limit must be taken into account. For good performance, it should be less than 2. (see the signals notation)

There is in principle no possibility to compute some robustness regions for input sensitivity function (ISF). However, you can check this function in PID Control Laboratory where you can also shape it interactively by hand.

 Complementary sensitivity function (CSF)Control sensitivity function (Su)