finally i received my DUET !
thanks to #ultiarjan for his directory; it helped me a lot.
I adapted it for the V3.1.1 firmware (h params in g1 codes, pt100 board adresses for themistors, and the adresses for endstops which are normally open in my case (i know it is not so good))
Heaters work well, (i use ultiarjan pid params) , and "home all" is ok.
I tried a little print yesterday:
it is really incredible: it make really less noise that drv8825 of my ultiboard !
It just still mechanic noise !
And i find that movements are "smoother"
i have to make some macros (stop motors, raise bed, preheat etc...)
tomorow i will try the zprobe (it is a new world for me !)