[Linuxptp-devel] how PI controller work in linuxptp

[Arnold kang]

hi all,
i'm reading the linuxptp code, and read pi.c many times, but i'm not sure
PI work in code . please help me , thanks!

ps, freq_est_interval = 0.016 / s->ki, why 0.016?

[Miroslav Lichvar]

Post by Arnold kang
hi all,
i'm reading the linuxptp code, and read pi.c many times, but i'm not sure
PI work in code . please help me , thanks!
ps, freq_est_interval = 0.016 / s->ki, why 0.016?

It's an experimentally determined value. With smaller ki the servo is
slower in ajdusting frequency, so the estimation interval is made
longer to get a more accurate starting value and decrease the overall
time needed to lock.

[Arnold kang]

thank you, but i still don't know how it work. i want to understand it
totally, please help me

Post by Miroslav Lichvar

Post by Arnold kang
hi all,
i'm reading the linuxptp code, and read pi.c many times, but i'm not

sure

Post by Arnold kang
PI work in code . please help me , thanks!
ps, freq_est_interval = 0.016 / s->ki, why 0.016?

It's an experimentally determined value. With smaller ki the servo is
slower in ajdusting frequency, so the estimation interval is made
longer to get a more accurate starting value and decrease the overall
time needed to lock.
--
Miroslav Lichvar

[Miroslav Lichvar]

Post by Arnold kang
thank you, but i still don't know how it work. i want to understand it
totally, please help me

How a PI controller works? I'm not sure that can be explained in a few
paragraphs in an email. I'd suggest to start with the wikipedia entry
on PID controllers.

[Arnold kang]

thank you!

Post by Miroslav Lichvar

Post by Arnold kang
thank you, but i still don't know how it work. i want to understand it
totally, please help me

How a PI controller works? I'm not sure that can be explained in a few
paragraphs in an email. I'd suggest to start with the wikipedia entry
on PID controllers.
--
Miroslav Lichvar