You can derive PID parameters by looking at a step response of the system, this is how I've read autotune units do it. Proportional control variable is self explanatory, and then the I and D parameters can be sussed out by looking at the slope and overshoot (if any) of the response curve. On Thu, Sep 1, 2011 at 6:35 PM, PICdude wrote: > PID does not seem difficult (and I found much info on it on the net), > but tuning is apparently a black art. =A0I don't know where to begin > with autotuning, but I suspect it would be some iterative process that > tweaks the P/I/D constants and determining how quickly it reaches the > target temp, and how much it drifts over time. > > If anyone here knows anything about autotuning, I'd love to be enlightene= d. > > Cheers, > -Neil. > > > > Quoting alan.b.pearce@stfc.ac.uk: > >> I would suggest you check the libraries that Microchip have for the >> dsPic devices, I have a feeling there is a PID library in there, but >> I haven't checked. >> >> Other than that actual PID code seems simple enough. I suspect it is >> the auto-tuning part that is the hard part. >> >> >> >> >> -- >> Scanned by iCritical. >> >> -- >> http://www.piclist.com PIC/SX FAQ & list archive >> View/change your membership options at >> http://mailman.mit.edu/mailman/listinfo/piclist >> > > > > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .