G-code motion target exceeds machine travel

Hello everyone

I have some issue like the following :

When I tried to control manually then got an error message “jog target exceeds machine travel. command ignored grbl gru”.

When I press “Yes” to exit program there was no response wit the grblgru, so that I need to reconnect my Arduino mega.

Sometimes show “alarm 2” and when I press “start homing” the Z-axis motor can’t stop running.
I know it’s a position problem and I tried to set all axis to zero but it still has an error.
I don’t know where it’s got wrong. Hope this problem can solve.


some details

  1. Arduino Mega 2560
  2. Ramps V1.4
  3. a4988 x5
  4. NEMA 17 stepper motor x 5
  5. 12V adaptor