@Donpi yes ,it works

@Phaedrux
Thanks every much,m98 p"config" give me inspire.

@Veti oh！！！thank to god，thank to duet，thank to dc42，This is my life-saving straw！！！

As this course ,i chonice P7 to sensing filament,i use a itr9608 made pcb to Detect rotation

However,when i connect it directly to duet3 ,It often works erratically.
Why? so I think maybe it doesn't produce pure pulses with the same width
I plan to use a singlechip to collect signal from itr9608,and send Pure pulse to duet3.

Questions:
1,Is my guess correct?
2 ,if its correct ,what is the standard of pulse?

@Veti oh！！！thank to god，thank to duet，thank to dc42，This is my life-saving straw！！！

OK,I will try this

Like that bro ,i using 1XD to build XY , find a similar problem:
https://forum.duet3d.com/topic/17780/clearpath-servos-with-1xd-expansion/74

I am 100% sure that servos are not loosing position too.
I can almost confirm the problem : some movement commands are being lost in transmission from the main board to the expansion board.

This is my test :
try use 2.7-50 in m569 no change ,no help
try use 80-600 in m92 no change ,no help
try use Slower speed more slwoer more normal
try different 3d model more simpely more normal
try to reduce face of model less mesh more normal

This my analysis:
if problem is by m569 or m92, it shoud affected only by move speed,and the less mesh model or simpely model should not return to normal,but it does normal
if problem is commands lost between can, less speed/simpely model/less mesh model can reduce CAN communication data in same time , i think it makes sences

more date in same time can make CAN lost commands ,so i think CAN transmission performance is not enough.

can it be fix by firmware update?
it is a very serious problems cause i have to delivery to customers soon, if cant fix that,i will lose hundreds of thousands of dollars

@chrishamm I dont know how to configure auto-mount utility ,i only try try "sudo gpasswd -a dsf disk"or"sudo gpasswd -a dsf pi.

@Phaedrux I updare to3.2fimal now,still cant fix that ,i think the promble up to duetpi but not duet3,and the disk can work normal at pc&raspie,i can put f11 to shut down webcontrol on duetpi , then i can see the disk on desktop and open it normal.

I choose ''sd card 2''in ''jobs'', it used to read the USB stick on the raspberry
But when i update to3.2 rc2 and update duetpi,i cant read stick now,the web control show me "faild to get file list,driectory 2not found"
I have try "sudo gpasswd -a dsf disk"or"sudo gpasswd -a dsf pi" and restart ,still faild.
QAQ ,is it has any way to fix that?

How to make a warning led by duet
I want every unnormal stat can make a red led work,like temp error/no filaments
I notic some error can trigger m25 ,so i try to put m42 in pause.g, for that,it works nice
But when i use pause by myself,led also can work,i dont want that,
So,is that have a better way to make warning led works only by something unnormal but not use pause by self.

@Phaedrux
Thanks every much,m98 p"config" give me inspire.

@Phaedrux Found the reason,if i del m501,everything normal,because i dont have configoverride at sys/.