Cause : Absolute system down error comes when the power of the encoder is out. This means the servo drive has lost its ability to accurately determine the motor's absolute position, which is crucial for precise motion control.

"alarm 40" in panasonic servo drive indicate "Absolute system down". This means an issue with the absolute encoder system. This error typically occurs when the drive loses the absolute position data, which is crucial for the servo system to know its exact position without needing to perform a homing procedure after power cycling.

1. Check the voltage of the battery.
2. Connect to the battery, and then clear the encoder using the absolute encoder clear mode contained in the auxiliary function.