Cause : Message buffer overflow comes when a message buffer overflow or non-cyclic send buffer (SDO response buffer) overflow.

Alarm value (r2124, interpret decimal):

1: Non-cyclic send buffer (SDO response buffer) overflow.
2: Non-cyclic receive buffer (SDO receive buffer) overflow.
3: Cyclic send buffer (PDO send buffer) overflow.

- check the bus cable.
- set a higher baud rate (p8622).
- check the bit timing and if required optimize (p8623).

Re alarm value = 2:

- reduce the cycle times of the SDO receive messages.
- SDO request from master only after SDO feedback for previous SDO request.