Fault location device, communication device, and fault location method

A first communication device in a communication system formed of the first communication device and a second communication device, wherein the first communication device and the second communication device carry out communications between each other through a two-wire communication line, each of the first and second communication devices being connected to the two-wire communication line by a respective pair of communication lines, wherein the first communication device comprises:

• a central processor;
• a storage unit that stores, using the central processor, a time of a communication error and a communication error counter accumulated value that indicates accumulated counts corresponding to the communication error;
• a control unit that changes, using the central processor, the first communication device into a bus off state on the basis of the error counter accumulated value and then, after a predetermined period of time has elapsed, returns the first communication device from the bus off state;
• an acquisition unit that acquires, using the central processor, the time of the communication error and the communication error counter accumulated value, which are stored in each of the first and second communication devices;
• and
• a detection unit that detects, using the central processor, that one communication line, from one of the respective pairs of communication lines is broken, but the other communication line from the one of the respective pairs of communication lines is not broken, on the basis of variations in the communication error counter accumulated values while one of the first and second communication devices is in a bus off state.

A fault location method for detecting a communication device connected to a broken communication line from among first and second communication devices that carry out communications between each other through a two-wire communication line, each of the first and second communication devices being connected to the two-wire communication line by a respective pair of communication lines, the fault location method comprising:

• if a communication error has been detected by the first communication device, then storing a time of the communication error and a communication error counter accumulated value that indicates accumulated counts corresponding to the communication error;
• changing the first communication device into a bus off state on the basis of the communication error counter accumulated value and then, after a predetermined period of time has elapsed, returning the first communication device from the bus off state;
• acquiring the time of the communication error and the communication error counter accumulated value, which are stored in each of the first and second communication devices;
• and
• detecting that one communication line, from one of the respective pairs of communication lines is broken, but the other communication line from the one of the respective pairs of communication lines is not broken, on the basis of variations in the communication error counter accumulated values of the first and second communication devices while one of the first and second communication devices is in a bus off state.

A non-transitory computer-readable storage medium storing instructions for causing at least one processor to execute a fault location method for detecting a communication device connected to a broken communication line from among first and second communication devices that carry out communications between each other through a two-wire communication line, each of the first and second communication devices being connected to the two-wire communication line by a respective pair of communication lines, the fault location method comprising:

• if a communication error has been detected by the first communication device, then storing, by the at least one processor, a time of the communication error and a communication error counter accumulated value that indicates accumulated counts corresponding to the communication error;
• changing, by the at least one processor, the first communication device into a bus off state on the basis of the communication error counter accumulated value and then, after a predetermined period of time has elapsed, returning, by the at least one processor, the first communication device from the bus off state;
• acquiring, by the at least one processor, the time of the communication error and the communication error counter accumulated value, which are stored in each of the first and second communication devices;
• and
• detecting, by the at least one processor, that one communication line, from one of the respective pairs of communication lines is broken, but the other communication line from the one of the respective pairs of communication lines is not broken, on the basis of variations in the communication error counter accumulated values of the first and second communication devices while one of the first and second communication devices is in a bus off state.