Arnie Grubbs wrote:
> 
> I don't understand why you would want to reset the "I" value....
> Maybe someone can clear this up for me...
.
.
.
> If you are worried about 'low freq' oscillations, and have to clear the "I"
> term for some reason, then I don't think you have your loop tuned correctly.
> If tuned correctly,  you would not normaly have any overshoot, or ringing
> action in the loop..

Can you tune a loop perfectly? I applied a PID controller to a 
linear motor, and found that I could minimise the energy (offset*time) 
needed to keep the damn thing still, by clearing the I term. 
If you make Ki too big, then you end up with oscillations. 
Make it too small, and the system never reaches setpoint. 
If you get it as close to perfect as you can with an 8 bit 
micro, you will always get low frequency oscillations.

The clearing of I is a modification to make the real 
world respond like a text book example ;) Hey, please 
don't tell my ex-professor ;)

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