Present position is always zero, it will not change no matter how the servo rotate.The error will occur when using joint mode，xl320 will rotate until it is overloaded.
If you turn off the Torque and rotate the horn by your hand, do you get correct Present Position value?
If the Present Position is not properly updated, the absolute position sensor could be damaged and not working.
In that case, you can request for repair service.
Yes, there is no value , even though i rotate the horn.
After i used Roboplus dynamixel wizzard to recovery xl320, something got wrong.
At first, the xl320 could not be found. Then, after about a week , i found the value is always 0.
i am not sure about that dose the recovery hurt it?