| 摘要 |
PURPOSE:To provide the right of transmission impartially by varying the priority of a node station in a loop transmission system having a synchronizing station. CONSTITUTION:The synchronizing station 7 transmits a synchronizing signal F of a prescribed period T0 to nodes 1-6 constituting a loop. This synchronizing signal F resets a timer of the node stations 1-6 and also starts the communication having the highest priority level sequentially. The synchronizing signal F consists of a preamble PR, a start flag SF, a synchronizing bit SY, priority bits P0, P1 and an end flag EF. The synchronizing signal is transmitted with the synchronizing bit SY=1 and the priority is designated in the descending order by the bits P0, P1 to provide the right of transmission. If the transmission of the node is failed because of low priority level regardless of the possession of a signal to be transmitted, the priority level is increased by one at the next frame. |
