| 摘要 |
PROBLEM TO BE SOLVED: To provide a technique for locating a cause of a transmission line abnormality without providing a special added circuit.SOLUTION: Transmission-message-residence determination means (34: S110 to S170) determines whether transmission is completed within preset specified time since a transmission request is generated. Transmission-error count means (35) increases or decreases a count value in response to the occurrence of an error related to a success or a failure in transmission and to transmission, and reception-error count means (35) increases or decreases a count value in response to an error related to a success or a failure in reception and to reception. Bus-off determination means (35) determines whether a state is a bus-off state in which participation in communication is prohibited in accordance with the count value of the transmission-error count means (35). Abnormality determination means (34: S210 to S300) determines whether a transmission line abnormality occurs and determines a cause of the abnormality in accordance with determination results of the transmission-message-residence determination means and the bus-off determination means and the count values of the transmission-error count means and the reception-error count means.SELECTED DRAWING: Figure 5 |
