The absolute position of the axis has not been established. This usually occurs after a battery failure in the absolute encoder or after moving the motor while the power is off. In this state, the machine will often throw a 300 APC ALARM: NEED ZRN (Zero Return).
She reconnected the motor cable, closed the cabinet, and looked at Cole. “Type G28 C0. Let’s see if it bites.” fanuc parameter 1860
You will typically need to interact with this parameter during: The absolute position of the axis has not been established