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Chapter 7: Computer Link Function
7
[9] Message transfers
(1) Outline of the message transfer process
The message transfer process is a function that allows asynchronous data to be exchanged be-
tween nodes.
The basic operation of the message transfer process is shown below.
1 When a node receives a token, it will send a maximum of one frame of message data before
the cyclic frame data sending.
2 A maximum of 1024 bytes can be sent at one time.
3 The JW-50FL uses an algorithm to prevent nodes from exceeding the allowable refresh cycle
interval for message transfers.
4 The JW-50FL has a "1:1" message transfer mode for sending to a specified node, and "1:N"
message transfer mode to send to all nodes.
5 It has a data send confirmation function used to check whether a target node has correctly
received the data in a "1:1" message transfer.
Outline of the message transfer process
Request
Node 1
"1:1" data transfer
Response
Node 2 Node 3 Node 4
Request
Node 1
"1:N" data transfer
Receive
Node 2
Node 3
Node 4
Receive
Receive