Rockwell Automation 1770-KF2 Data Highway or Highway Plus Interface Module User Manual - Manual (Page 180)

Error Reporting
Chapter 7
7Ć25
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 #8. 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 will 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.
16. Aborts: Counts the number of aborts received. The HDLC abort
signal is not used on the Data Highway, but can be detected by the
SIO in certain circumstances. Some stations whose addresses match
the ringing pattern after a transmitter shutoff can be particularly
susceptible to this error (Stations 36, 76, and 176 for example).
These numbers will depend on highway configurations.
17. Transmitted Messages: A 16-bit counter that records the number of
messages successfully transmitted.
18. Not used.