PID Timing

[Tom Line]

If seems to me that PID Loops are time dependent. After all, you have the derivative term which is essentially monitoring the change in your error term.

My question then, is why the derivative term isn't normalized for time (divided by the loop timing) to account for loops changing speed. In the past, we've not used "D" terms, but it seems that when the cpu starts to get loaded down, the D term could cause issues due to varying loop timing.

Am I off base?