Bosch, Fault confinement – Rainbow Electronics CAN интерфейс User Manual

Page 65

BOSCH

ROBERT BOSCH GmbH, Postfach 300240, D-7000 Stuttgart 30

Sep. 1991

Part B - page 63

10. A node is ’bus off’ when the TRANSMIT ERROR COUNT is greater than or equal to

256.

11. An ’error passive’ node becomes ’error active’ again when both the TRANSMIT

ERROR COUNT and the RECEIVE ERROR COUNT are less than or equal to 127.

12. An node which is ’bus off’ is permitted to become ’error active’ (no longer ’bus off’)

with its error counters both set to 0 after 128 occurrence of 11 consecutive
’recessive’ bits have been monitored on the bus.

Note:
An error count value greater than about 96 indicates a heavily disturbed bus. It may be
of advantage to provide means to test for this condition.

Note:
Start-up / Wake-up:
If during start-up only 1 node is online, and if this node transmits some message, it will
get no acknowledgment, detect an error and repeat the message. It can become ’error
passive’ but not ’bus off’ due to this reason.

Fault Confinement