Troubleshooting
372 SPU 780 01EMAN May 2002 285
Communication
Status 2/2 (S901) The Remote I/O communication Status Word 2 shows errors and the retry count on
lost communications. If communications is lost with the channel pair then the
corresponding error bit will be set and the retry counter will increment. If the retry
counter counts to maximum then other indicators will be affected.
Module health will show as ’0’. If communication is re-established, this error count
and error word is not cleared. The only way to clear this word is to cycle power on
the controller or issue a start and stop command.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Retry counter
1 = Command not supported by drop
1 = Invalid frame number
1 = Drop just powered up
1 = Address did not respond
1 = CRC error from address drop
1 = Character overrun error from addressed drop