A7AB warning in ABB DCS880 drive indicates I/O extension configuration. This means the I/O extension module/DCSLink board (SDCS-DSL-H1x) types and locations specified by parameters do not match the detected configuration or do not communicate with the drive.

1. Check the type and location settings of the modules/board. See parameters 14.01, 14.02, 15.01, 15.02, 16.01, 16.02, 70.01, 70.02, 70.05 and 70.07.
2. Check that the module/board is properly seated in its slot.
3. Check that the module/board and the slot connector is not damaged.
4. Try installing the module into another slot.