PID Loops

[Ether]

Originally Posted by WizenedEE

The derivative takes the current speed and somehow uses that to adjust the speed? How does it do that?

The derivative subtracts the previous value of the process variable from the current value of the process variable and divides the result by the elapsed time between the two to get an approximation of the time rate of change of the process variable. This is then multiplied by a gain and added to the contributions from the P and I calculations.