Diagnostic apparatus and system adapted to diagnose occurrence of communication error

A diagnostic apparatus being connected to a plurality of communication apparatuses via a communication bus, diagnosing at least one communication apparatus, the diagnostic apparatus comprising:

• monitoring means for monitoring a control data signal sent from the communication apparatuses at a predetermined period;
• first determining means for determining a communication apparatus to be diagnosed from among the plurality of communication apparatuses based on a result of the monitoring;
• start signal transmitting means for transmitting a start signal to the communication apparatuses that periodically send the control data signal when the first determining means determines the communication apparatus, the start signal being used to notify the communication apparatuses about starting of a diagnostic test;
• first receiving means for receiving accept signals responding to the start signal, the accept signals being sent from the communication apparatuses;
• test signal transmitting means for transmitting a plurality of test signals to the communication apparatuses that send the accept signals, when the first receiving means receives the accept signals, the test signals being uniquely recognizable each other;
• second receiving means for receiving a response signal sent from the communication apparatuses, the response signal being recognizable as a signal responding to each test signal transmitted by the transmitting means;
• second determining means for determining whether or not the second receiving means receives the response signal corresponding to each test signal within a predetermined period that limits an elapsed time counted from a time when the test signal is transmitted;
• and
• diagnosis means for diagnosing whether or not a communication error occurs between the diagnostic apparatus and the communication apparatus based on the determining results for respective response signals determined by the second determining means.

A diagnostic system comprising:

• a plurality of communication apparatuses that transmit a control data signal at a predetermined period;
• a diagnostic apparatus connected to the plurality of communication apparatuses via a communication bus, diagnosing at least one communication apparatus;
• monitoring means adapted to the diagnostic apparatus for monitoring the control data signal transmitted from the communication apparatuses;
• first determining means adapted to the diagnostic apparatus for determining a communication apparatus to be diagnosed from among the plurality of communication apparatuses based on a result of the monitoring;
• test signal transmitting means adapted to the diagnostic apparatus for transmitting a plurality of test signals to the communication apparatus to be diagnosed when the determining means determines the communication apparatus, the test signals being uniquely recognizable each other;
• responding means adapted to the communication apparatus for responding to each transmitted test signal by sending a response signal to the diagnostic apparatus when the communication apparatus receives the test signal, the response signal being recognizable as a signal responding to each test signal transmitted by the transmitting means;
• second determining means adapted to the diagnostic apparatus for determining whether or not the diagnostic apparatus receives the response signal corresponding to each test signal within a predetermined period that limits an elapsed time counted from a time when the test signal is transmitted;
• and
• diagnosis means adapted to the diagnostic apparatus for diagnosing whether or not a communication error occurs between the diagnostic apparatus and the communication apparatus based on the determining results for respective response signals determined by the second determining means.

A diagnostic system comprising:

• a plurality of communication apparatuses that transmit a control data signal at a predetermined period;
• a diagnostic apparatus connected to the plurality of communication apparatuses via a communication bus, diagnosing at least one communication apparatus;
• monitoring means adapted to the diagnostic apparatus for monitoring the control data signal transmitted from the communication apparatuses;
• first determining means adapted to the diagnostic apparatus for determining a communication apparatus to be diagnosed from among the plurality of communication apparatuses based on a result of the monitoring;
• start signal transmitting means adapted to the diagnostic apparatus for transmitting a start signal to the communication apparatuses that periodically transmit the control data signal when the first determining means determines the communication apparatus, the start signal being used to notify the communication apparatuses about starting of a diagnostic test;
• extending means adapted to the communication apparatus for extending the predetermined period used for transmitting the control data signal when the communication apparatus once receives the start signal;
• accept signal returning means adapted to the communication apparatus for returning an accept signal to the diagnostic apparatus when the communication apparatus receives the start signal transmitted by the start signal transmitting means;
• test signal transmitting means adapted to the diagnostic apparatus for transmitting a plurality of test signals to the communication apparatuses that transmit the accept signals, when the diagnostic apparatus receives the accept signal, the test signals being uniquely recognizable each other;
• test signal responding means adapted to the communication apparatus for responding to each transmitted test signal by sending a response signal to the diagnostic apparatus when the communication apparatus receives the test signal, the response signal being recognizable as a signal responding to each test signal transmitted by the transmitting means;
• second determining means for determining whether or not the diagnostic apparatus receives the response signal corresponding to each test signal within a predetermined period that limits an elapsed time counted from a time when the test signal is transmitted;
• and
• diagnosis means for diagnosing whether or not a communication error occurs between the diagnostic apparatus and the communication apparatus based on the determining results for respective response signals determined by the second determining means.

A diagnostic method executed on a diagnostic apparatus being connected to a plurality of communication apparatuses via a communication bus, diagnosing at least one communication apparatus, the method comprising steps of:

• monitoring a control data signal sent from the communication apparatuses at a predetermined period;
• determining a communication apparatus to be diagnosed from among the plurality of communication apparatuses based on a result of the monitoring;
• transmitting a plurality of test signals to the communication apparatus to be diagnosed when the communication apparatus is determined;
• receiving a response signal sent from the communication apparatus to be diagnosed;
• determining whether or not the diagnostic apparatus receives the response signal corresponding to each test signal within a predetermined period that limits an elapsed time counted from a time when the test signal is transmitted;
• and
• diagnosing whether or not a communication error occurs between the diagnostic apparatus and the communication apparatus based on the determining results for respective response signals.

A diagnostic method executed on a diagnostic apparatus being connected to a plurality of communication apparatuses via a communication bus, diagnosing at least one communication apparatus, the method comprising steps of:

• monitoring a control data signal sent from the communication apparatuses at a predetermined period;
• determining a communication apparatus to be diagnosed from among the plurality of communication apparatuses based on a result of the monitoring;
• transmitting a start signal to the communication apparatuses that periodically send the control data signal when the communication apparatus is determined;
• receiving accept signals responding to the start signal, the accept signals being sent from the communication apparatuses;
• transmitting a plurality of test signals to the communication apparatuses that send the accept signals, when the diagnostic apparatus receives the accept signals;
• receiving a response signal sent from the communication apparatuses, the response signal being recognizable as a signal responding to each test signal;
• determining whether or not the diagnostic apparatus receives the response signal corresponding to each test signal within a predetermined period that limits an elapsed time counted from a time when the test signal is transmitted;
• and
• diagnosing whether or not a communication error occurs between the diagnostic apparatus and the communication apparatus based on the determining results for respective response signals determined by the second determining means.