| 摘要 |
PURPOSE:To utilize effectively communication capacity of a line by executing communication for plural number of times while the control right of communication is held within a range where a cyclic communication number exceeds a prescribed value when the communication number is less than a prescribed value and plural communication requests exist in the own station. CONSTITUTION:Stations S1, S2 having a communication control function are connected via a common transmission line Ln. A master station acquiring a communication control token and performing communication compares a communication number M of the entire communication system during the cycle of preceding token with a station number N connected to the line Ln, and when the number N is larger than the number M, and the difference is taken as a communication permitting number L this time. A count M of the counter counting the communication number of one cycle of next time is initialized to 0, and when communication request exists, it is processed and 1 is added to the counter. When M<L exists, the communication request is processed, and when the communication request is lost or M<L does not exist, the token is sent to the next station and the master right is taken over. Thus, the line communication capacity is utilized effectively.
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