| 摘要 |
A method for the transmission of cyclic data among stations in a looped transmission path which performs operations to bring the data in a shared cyclic memory up to date in a distribution control transmission system wherein a synchronous cyclic data transmission and an asynchronous event transmission are both included. In one aspect, the shortest token rotation time is first counted where synchronous cyclic data only are transmitted, and the timing of data transfer to a transmission buffer memory is thereafter selected to be such shortest token rotation time after the capture of a token by a station. In the second aspect, a dummy frame which cannot be received by any one of the stations in the loop is transmitted and synchronous data frames which have been queued in the transmission buffer memory are brought up to data by data in the cyclic memory during the transmission of the dummy frame. The transfer of synchronous data to the buffer memory is thus performed during the shortest token rotation time or during the dummy frame transmission time.
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