PID control loops - closed loop feedback

[Max Lobovsky]

Originally Posted by Larry Barello

You must limit the integral term: what happens when your output is at 100% and you STILL have an error term? DO you really want to continue accumulating errors? It is a bad idea and will cause excessive delays in working out the integral term (the official name for this is Integral Windup) when you regain control.

ok, but i thought the solution to that is to sum over a shorter period of time and use a small enough coeffecient. The integral term just becomes an additional proportional term in the code posted above when the error is large enough.

.... on second though, that isnt really a problem as the integral term isn't needed when the error is large. And i was presumptious enough to think that years of science and engineering could be faulty....

So what this means is that if one limits the integral each iteration, one can integrate for the entire time the robot functions? I understand this would work now, but it still seems a little odd, id rather just integrate for a shorter period of time. Is this common practice?