Industrial network apparatus and data communication method

A data communication method comprising:

• transmitting priority data by an industrial network apparatus that includes an upstream communication interface and a downstream communication interface in a priority transmission period that occurs periodically;
• determining whether or not to start transmission of non-priority data in a non-priority transmission period that is different from the priority transmission period depending on a required transmission time of non-priority data and remaining time of the non-priority transmission period;
• receiving priority data by the industrial network apparatus;
• starting transmission of the received priority data by the industrial network apparatus during the priority transmission period before the entire priority data is received for every transmission of received priority data that includes a command;
• and
• transmitting the non-priority data by the industrial network apparatus when determining to start transmission of the non-priority data, the transmission of the non-priority data performed by transmitting non-priority data via the upstream communication interface in a period of time that overlaps the transmitting priority data.

An industrial network apparatus comprising:

• an upstream communication interface;
• a downstream communication interface;
• control data communication means for receiving and transmitting control data in a priority transmission period that occurs periodically, and for starting a transmission of received control data during the priority transmission period before the entire control data is received for every transmission of received control data that includes a command;
• and
• message data communication means for determining whether or not to start transmission of message data in a non-priority transmission period that is different from the priority transmission period depending on a required transmission time of message data and remaining time of the non-priority transmission period, and also transmitting the message data when determining to start transmission of the message data, wherein
• the message data communication means is configured to transmit message data via the upstream communication interface such that the message data is transmitted in a period of time that overlaps the transmission of control data by the control data communication means.