Thanks for your Help.
But i think i dont really understand. Why cant (or shouldnt) i use it in this section?
I tried to use it in save_z_home and the setting of the variable now seems to work, but there seems to be an error when reading this value.
Error:
Unable to parse option ‘home_xy_position’ in section ‘safe_z_home’
I tried bed_x_max,bed_y_max and {bed_x_max},{bed_y_max}