Rockwell Automation 1770, D17706.5.16 Ref Mnl DF1 Protocol Command User Manual

Page 155

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9–17

Diagnostic Counters

Publication 1770Ć6.5.16 - October 1996

This counter byte Counts the number of
8

Times the receiver received a status frame instead of a message

frame.

This occurs if a poll timeout is imminent (a master has had

mastership for more than 170ms) and the node has disabled its

address recognizer to test for any valid traffic. The probability of

errors in counter bytes 8, 9 and 10 increases substantially.

9

Frames that were rejected because the header was incomplete.

This is only counted because of undebugged software or in the

unlikely event that a bad frame fooled the CRC checker.

10

Frames that were rejected because the destination address was

incorrect.

This can have the same cause as counter byte 8. This counter also

detects frames that have the same source and destination

addresses.

11

Times that the receiver sent an ACK without first being able to

allocate a receive buffer.

This results in a memory overflow error when the next messages is

received

12

Frames that were rejected because of a bad CRC.

This error is common on a noisy link.

13

Times a message was received that contained more than 250
bytes

.

14

Times a message was received when there was no buffer space

allocated for it.

This usually follows a memory full" error.

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