Cyclic Transmission And Area - Hitachi FL.NET User Manual

5.1.8 Cyclic transmission and area

(1) Cyclic transmission overview
The cyclic transmission function uses the common memory to periodically exchange data.
• Transmits data when the node holds the token.
• Recognizes nodes conducting no cyclic transmission as far as they participate in the
network.
• Ensures that all the cyclic data to be transmitted are transmitted when the token is held.
Token: Only one token basically exists within the network. If two or more tokens should
exist within the network, the one with the lowest destination node number takes
precedence with the others discarded.
Token frame: A token frame (frame that contains the token) consists of a token destination
Token sequence: The order of token rotation is determined by a node number. Token
node number and token transmission node number.
A node becomes a token holder when it agrees with the destination node
number for the token in a token frame it receives.
rotation occurs in the ascending order of nodes registered in the
participating node management table. A node having the maximum
node number passes the token to a node having the minimum node
number.
5-11
5 USER GUIDE