When this switch is pressed, the indicator in the switch is lit and the zero return mode is selected.In the zero return mode, the axis (X-/Z-axis) is manually returned to the zero point.The operation is impossible with the PANEL key-switch placed in the 0 PANEL position.Close the front door before carrying out the zero return operation.The axes are fed at rapid traverse rate during the zero return operation.Pay sufficient attention and make sure that the axes can be returned to the zero point without interference.