Addressed device backplane failed to respond to selection.
Problem determination
If there are multiple xxxx3002 reference codes logged from the same disk expansion unit at about the same time
suspect an input power failure. Verify that
input power to the expansion unit power supplies was active at the time of the error.
If input power to the expansion unit failed the expansion unit was not able to log a reference code for the input power failure.
Restore power to the expansion unit and close the xxxx3002 problems. Otherwise work the xxxx3002 reference codes.