What is PIDF?

[geniusadam69]

Originally Posted by Ether

Could you please explain what you mean by this?

I don't think what he wrote is correct. A tuned controller will definitely reach its setpoint. The only thing I will point out is that a setpoint must have tolerances, otherwise, it can never truly hit an exact number.

That said, if you're not familiar with PID, you should google this and there's tons of information on it. Quick Summary:
E is error. This is the difference between value and setpoint.

P is proportional. so if Kp*E = output
I is integral, so sum (E) *Ki = output
D is derivative, so (E,now - E,last) *Kd = output

If you add all of these together you'll get an actual output from a PID controller. That's a quick summary and it's likely not occurring actually like that, but it gives you a general idea.

proportional is designed to do most of the work. Integral is designed to push small errors towards the setpoint. Derivative is usually designed to counteract strong pushes.