Fault localization and health indication for a controller area network

• US 20020166088A1
• Filed: 06/26/2002
• Published: 11/07/2002
• Est. Priority Date: 12/14/1999
• Status: Active Grant

• Current Assignee: Isabelle Dierauer, Peter P. Dierauer
• Original Assignee: Isabelle Dierauer, Peter P. Dierauer
• Inventors: Dierauer, Peter P., Dierauer, Isabelle
• Granted Patent: US 6,959,403 B2
• Time in Patent Office: Days
• US Class Current: 714/704
• CPC Class Codes: H04L 41/0677 Localisation of faults

Abstract

A node of a network comprises an error message detector arranged to detect error messages transmitted over the network, a counter arranged to count the error messages in order to produce an error message count, and a controller arranged to count valid messages in order to produce a count of valid messages. The controller is arranged to compare the error message count to the valid message count to indicate the health of the network. The node further comprises a transceiver, a controller coupled to the transceiver by a receive line and a transmit line, and error message first logic coupled to the receive and transmit lines. The error message first logic is arranged to detect a first error message from the receive line and a second error message from the transmit line, and to determine whether the node is closest to a fault by comparing timing between the first error message and the second error message.

Claims

1. A method of determining health of a network comprising the following steps:

a) determining a number of error messages transmitted over the network;

b) determining a number of valid messages transmitted over the network; and

,

c) comparing the number of error messages to the number of valid messages in order to determine the health of the network.

2. The method of claim 1 wherein valid messages are non-error messages.

3. The method of claim 1 wherein step b) comprises the following steps:

b1) determining a number of all messages; and

,

b2) subtracting the number of error messages from the number of all messages.

4. The method of claim 1 wherein step c) comprises the step of calculating a ratio between the number of error messages and the number of valid messages.

5. The method of claim 4 wherein step b) comprises the following steps:

b1) determining a number of all messages; and

,

b2) subtracting the number of error messages from the number of all messages.

6. The method of claim 4 wherein the step of calculating the ratio comprises the step of dividing the number of error messages by the number of valid messages.

7. The method of claim 6 wherein step b) comprises the following steps:

b1) determining a number of all messages; and

,

b2) subtracting the number of error messages from the number of all messages.

8. The method of claim 4 comprising the further step of calculating the ratio over a plurality of time intervals and monitoring a trend of the ratios.

9. The method of claim 1 further comprising the following steps:

d) repeating steps a)-c) over a plurality of time intervals; and

,

e) monitoring a trend of the health of the network based upon results from step d).

10. A node of a network comprising:

an error message detector arranged to detect error messages transmitted over the network;

a counter arranged to count the error messages in order to produce an error message count; and

,

a controller arranged to produce a count of valid messages and to compare the error message count to the valid message count.

11. The node of claim 10 wherein valid messages are non-error messages.

12. The node of claim 10 wherein the error message detector and the counter are part of the controller.

13. The node of claim 10 wherein the controller is further arranged to determine an all message count and to subtract the error message count from the all message count in order to produce the valid message count.

14. The node of claim 10 wherein the controller is arranged to calculate a ratio between the error message count and the valid message count.

15. The node of claim 14 wherein the controller is arranged to calculate the ratio over a plurality of time intervals and to monitor a trend of the ratios.

16. The node of claim 14 wherein the controller is further arranged to determine an all message count and to subtract the error message count from the all message count in order to produce the valid message count.

17. The node of claim 14 wherein the controller is arranged to calculate the ratio by dividing the error message count by the valid message count.

18. The node of claim 17 wherein the controller is arranged to determine an all message count and to subtract the error message count from the all message count in order to produce the valid message count.

19. The node of claim 10 wherein the controller is arranged to calculate a ratio between the error message count and the valid message count over a plurality of time intervals and to monitor a trend of the health of the network based upon the ratios.

20. A method of determining a location of a fault comprising the following steps:

a) detecting a first error message from a receive line of a node;

b) detecting a second error message from a transmit line of the node;

c) if the first error message is detected before the second error message, determining that the node did not first transmit the second error message; and

,

d) if the second error message is detected before the first error message, determining that the node may have first transmitted the second error message.

21. The method of claim 20 wherein step d) comprises the following steps:

d1) determining a time difference between the first and second error messages; and

,

d2) determining that the node did first transmit the second error message if the time difference is greater than a transceiver delay.

22. The method of claim 20 wherein step d) comprises the following steps:

d1) determining a time difference between the first and second error messages; and

,

d2) determining that the node did not first transmit the second error message if the time difference is less than a transceiver delay.

23. The method of claim 22 wherein step d) farther comprises the following step:

d3) determining that the node did first transmit the second error message if the time difference is greater than the transceiver delay.

24. The method of claim 20 further comprising the step of transmitting a message indicating first detection of a fault.

25. The method of claim 20 further comprising the step of counting a number of times that the node did first transmit the second error message.

26. The method of claim 25 wherein step d) comprises the following steps:

d1) determining a time difference between the first and second error messages; and

,

d2) determining that the node did first transmit the second error message if the time difference is greater than a transceiver delay.

27. The method of claim 25 wherein step d) comprises the following steps:

d1) determining a time difference between the first and second error messages; and

,

d2) determining that the node did not first transmit the second error message if the time difference is less than a transceiver delay.

28. The method of claim 27 wherein step d) farther comprises the following step:

d3) determining that the node did first transmit the second error message if the time difference is greater than the transceiver delay.

29. The method of claim 25 further comprising the step of transmitting a message indicating the number.

30. A node comprising:

a transceiver coupled to a communication line;

a controller coupled to the transceiver by a receive line and a transmit line; and

,

error message first logic coupled to the receive and transmit lines, wherein the error message first logic is arranged to detect a first error message from the receive line and a second error message from the transmit line, and wherein the error message first logic is arranged to determine whether the node is closest to a fault by comparing timing between the first error message and the second error message.

31. The node of claim 30 wherein the error message first logic is arranged to determine that the node is closest to the fault by determining a time difference between the first and second error messages and by determining that the node transmitted the second error message first if the time difference is greater than a transceiver delay.

32. The node of claim 30 wherein the error message first logic is arranged to determine that the node is not closest to the fault by determining a time difference between the first and second error messages and by determining that the node did not transmit the second error message first if the time difference is less than a transceiver delay.

33. The node of claim 30 wherein the error message first logic is arranged to determine that the node is not closest to the fault by determining that the node received the first error message before it transmitted the second error message.

34. The node of claim 30 wherein the transceiver is arranged to transmit a message indicating first detection of the fault.

35. The node of claim 30 further comprising a counter arranged to count a number of times that the node did determine that it is closest to the fault.

36. The node of claim 35 wherein the error message first logic is arranged to determine that the node is closest to the fault by determining a time difference between the first and second error messages and by determining that the node transmitted the second error message first if the time difference is greater than a transceiver delay.

37. The node of claim 35 wherein the error message first logic is arranged to determine that the node is not closest to the fault by determining a time difference between the first and second error messages and by determining that the node did not transmit the second error message first if the time difference is less than a transceiver delay.

38. The node of claim 35 wherein the error message first logic is arranged to determine that the node is not closest to the fault by determining that the node received the first error message before it transmitted the second error message.

39. The node of claim 35 wherein the transceiver is arranged to transmit a message indicating the number.

40. The node of claim 35 wherein the error message first logic and the counter are part of the controller.

41. The node of claim 30 wherein the error message first logic is part of the controller.