A8A0 warning in ABB DCS880 drive indicates AI supervision. This means an analog signal is outside the limits specified for the analog input.

1. Check the signal level at the analog input.
2. Check the wiring connected to the input.
3. Check polarity of the connection.
4. Check the minimum and maximum limits of the input in groups 12 Standard AI, 14 I/O extension module 1, 15 I/O extension module 2 and 16 I/O extension module 3.