Chapter 7: Computer Link Function

(2)Message transfer

The maximum amount of data that can be transferred in one message frame is 1024 bytes (exclud- ing the header section).

Message frame

1024 byes

Message transfer data limit

[5] Transfer cycle

In the cyclic transfer operation, the JW-50FL refreshes the common memory almost constantly. The JW-50FL controls the transfer of messages so that the refresh interval of the common memory does not exceed the allowable refresh cycle interval for a single message transfer.

Each node always monitors the messages being transferred throughout the network, waiting to receive a token addressed to itself. If no message transferred by the network within this cycle, the refresh cycle interval is increased to 120 % of its current value.

Due to the monitoring process above, the refresh cycle interval is automatically determined by the number of nodes active on the network.

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