The characteristics of a mode of controller are summarized:
1) If error is zero, the output from the controller is zero.
2) If error is constant in time, the output from the controller is zero.
3) For changing error in time, the output from the controller is |K|% for every 1% sec–1 rate of change of error.
4) For positive rate of change of error, the output is also positive.
The mode of controller is