Communication system and communication device

A communication system, comprising

• a plurality of communication devices connected to each other via a common communication line, and each including a message generation part generating a message with information concerning a priority, a message transmission part outputting a signal in accordance with a message generated by the message generation part to the communication line to transmit the message and a message reception part obtaining a signal by sampling for the communication line to receive a message concerning the signal in accordance with the information;
• and an arbitration part arbitrating an order of transmission in accordance with priorities of messages in a case where transmission of the messages by the plurality of communication devices collide against each other, the plurality of communication devices transmitting/receiving a message to/from each other via a common communication line,
• wherein at least one of the communication devices comprises:
• a determination part determining whether or not a message received by the message reception part is transmitted in sequence with another message;
• and
• a delay time estimation part estimating, if the determination part determines that the received message is transmitted in sequence, delay time of the received message caused by arbitration of the arbitration part in accordance with a priority of sequential one or more messages preceding the received message.

A communication device connected to a different device via a common communication line, comprising:

• a message generation part generating a message with information concerning a priority;
• a message transmission part outputting a signal in accordance with a message generated by the message generation part to the communication line to transmit the message;
• a message reception part obtaining a signal by sampling for the communication line to receive a message concerning the signal in accordance with the information;
• and an arbitration part arbitrating an order of transmission in accordance with a priority of the message in a case where transmission of messages collide against each other between the communication device and the different device, the communication device transmitting a message to the different device and receiving a message from the different device via a common communication line, further comprising:
• a determination part determining whether or not a message received by the message reception part is transmitted in sequence with another message;
• and
• a delay time estimation part estimating, if the determination part determines that the received message is sequentially transmitted, delay time of the received message caused by arbitration of the arbitration part in accordance with a priority of sequential one or more messages preceding the received message.