| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent a control signal for establishing synchronism from being transmitted on a bus by setting a portal where the number of hops in nodes to a network clock reference node is minimum in connection to the bus by the bus without the connection of the network clock reference node. SOLUTION: The cycle frequency of a portal A adjacent to the portal B of a net cycle master can be synchronized with the portal B. Since a portal C is connected to the same bus 40 as the portal B, the cycle frequency is synchronized with the portal B with the cycle start packet of the transmission of the portal B. Thus, a portal D can be synchronized with the adjacent portal C. Portals F and H can indirectly be synchronized with the cycle frequency of the portal B in a way similar to the portal D. When the cycle frequency of the whole portal cycle master is synchronized with the portal B of the net cycle master, the synchronism of the whole network is established. The local cycle masters are arranged in respective buses and synchronism can be established even in existing unit connection.</p> |
