AL072 alarm in delta servo drive indicates Encoder overspeed. This means encoder is powered by the servo drive: the speed is over 8,800 rpm or the acceleration exceeds 1×105 rad/s2.

1. Check if the motor is well grounded.
2. Check if the encoder cable is separated from the power supply or any high-current cable to avoid interference.
3. Check if the encoder uses shielded cable.