Rockwell Automation 1770-KF2 Data Highway or Highway Plus Interface Module User Manual - Manual (Page 183)

Error Reporting
Chapter 7
7Ć28
hear it, the old master will record a false poll and continue polling;
and the new master will start polling also. This usually leads to the
second station detecting contention and relinquishing.
8. Receiver Heard Status: Counts the number of times that the
receiver received a status frame instead of a message frame. (This
counter will never be incremented because the message size is
checked first, and all status messages are too small to be accepted.)
9. Frame Too Small: Counts the number of frames that were rejected
because they were less than 6 bytes long. This counter will record all
status frames that were received by a station that disabled its address
recognizer in the second step of the mastership timeout process. This
will happen often on a heavily loaded highway.
10. Wrong Destination Address: Counts the number of frames that
were rejected because the destination address was incorrect. This
can have the same cause as #9. This counter also detects frames that
have the same source and destination address.
11. Receiver/Memory Full: Counts the number of times that the
receiver sent an ACK without first being able to allocate a receive
buffer. This may result in a memory overflow error when the next
message is received.
12. Bad Frame Status: Counts the number of frames that were rejected
because of a bad CRC. This error is very common on a noisy
highway.
13. Buffer Overflow: Counts the number of times a message was
received that contained more than 250 bytes.
14. Memory Overflow: Counts the number of times a message was
received when there was no buffer space allocated for it. This
usually follows a “memory full” error.
15. Retransmits: Counts the number of duplicate frames received. A
duplicate frame is sent by a transmitter when it fails to receive an
ACK. If the reason it failed to receive an ACK was that the ACK
was lost, rather than because the original message was lost, the
duplicate is redundant and should be discarded. Any two successive
messages between polls that have the same sequence number fields
and the same command/reply bit are assumed to be duplicates.