what is HOME in TRAJ mean?

i read document but i didnt understand how it work, i tried random change it but i didnt see anything change when i run linuxcnc

linuxcnc.org/docs/2.7/html/config/ini-config.html#_traj_section

HOME = 0 0 0 - Coordinates of the homed position of each axis. Again for a fourth axis you will need 0 0 0 0. This value is only used for machines with nontrivial kinematics. On machines with trivial kinematics this value is ignored.

Without more info it's hard to help you.
If your machine is a regular XYZ machine then it does nothing - it's ignored.

Chris M

my machine is an robot arm 6dof like puma560. I have set home's joints are 0 0 0 0 -90 0

I'm sorry I don't know much about non trivial kin machines.
Hopefully someone else can answer.
More information about your machine would help.
posting your config files would help.

Chris M