Hi Backing up a bit …. the objective is not to minimize overshoot or keep the loop from oscillating. The issue here is optimizing the noise output of the combination of GPS + OCXO when combined via the control loop. It’s a very different objective ….
Bob > On Mar 7, 2020, at 8:01 PM, Bill Hawkins <[email protected]> wrote: > > Try https://en.wikipedia.org/wiki/PID_controller > > If that doesn't help, what we used to do for industrial process controllers > was to set Reset time to the largest value and Derivative to zero (to disable > them) and then increasethe gain until the loop oscillated when you made a > step change to the setpoint, then you used 70% of that value for gain. The > period of oscillation told you how to do Reset, but I don't remember that. > Conservative settings were used because control valves were not linear. > Heaters are generally linear. > > Bill Hawkins, whose memory isn't what it used to be. > > On Sat, Mar 7, 2020, at 5:04 PM, Hal Murray wrote: >> >> [email protected] said: >>> As far as I know there is no “closed form” solution to tuning a GPSDO. It is >>> very much a measure / tweak / measure / tweak sort of thing. >> >> I've seen a recipe for tuning a PID controller. That was ages ago. I wonder >> where. >> >> The key idea was that you needed to be able to poke the system and see how >> it >> responded. >> >> Google for >tune PID< gets several hits that might be worth investigating. >> >> >> -- >> These are my opinions. I hate spam. >> >> >> >> >> >> _______________________________________________ >> time-nuts mailing list -- [email protected] >> To unsubscribe, go to >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >> and follow the instructions there. >> > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
