Geeetech

Hi, I installed 3D Touch and try to calibrate it. The problem: I cannot enter the needed z offset value - after "M851 Z-1.69" I got the feedback:
>>> M851 Z-1.69
SENDING:M851 Z-1.69
echo:Z Offsetz_min: -15z_max: -5

Where can I change these z_max values?!

Thanks! 10.0.0.0.1 192.168.1.254