First order P + I control

Cuthbert Nyack

First order system with P + I control. These applets indicate how some of the disadvantages of proportional controllers can be reduced or eliminated bt P + I controllers. In particular, it is now possible to have the desired value equal to the actual value obtained. Also a disturbance produces a transient move away from the set point, but it returns to the desired value. The following applets allow interactive investigation of how K, Ti and the time constant affect the behaviour of the system.

The unit input step is shown as the purple line. The output response is shown in red. The horizontal axis corresponds to 4 seconds.

First order system with P + I control and noise.

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