7 ) assurance of data concurrency – Yaskawa JAPMC-MC2303-E User Manual
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Details of FL-net
5.3 FL-net Data Communication
5.3.1 Cyclic Transmission
5-11
( 6 ) Common Memory Broadcast
In FL-net cyclic transmission, a token holding node broadcasts data in the area assigned for the node (simultaneous
send communication).
The common memory provides a function for allowing each node to broadcast data in a specific period so that the same
data can be shared in the entire system. Nodes on FL-net respectively employ non-duplicate send areas for data
exchange. In common memory operations, a send area assigned for a certain node serves as a receive area for the other
node.
The common memory can be used only for a receive area.
( 7 ) Assurance of Data Concurrency
When the data size sent by one node exceeds the single frame transmission size, i.e., 1,024 bytes, data is transmitted by
multiple frames. When a segmented data frame is received, common memory is not updated until all frame from one
node is received. The common memory assures data concurrency in units of nodes according to the following proce-
dure.
[ a ] Frame Segmentation when Sending
When a data send request is sent from the upper layer (at the SCAN timing set by link assignment), the node copies its
cyclic data to the buffer, makes preparations for sending, and then sends data sequentially. In this case, however, when
the sending node data size is larger than the size of single frame send data, buffer data is segmented into multiple
frames for sending.
[ b ] Refresh Operation when Receiving
When a receiving node has received all cyclic data from one node, it updates the upper layer and the area to be pro-
cessed synchronously (it updates the input register value at the SCAN timing set by link assignment).
Even when cyclic data is sent in units of frames, it updates area at the timing when all frame data from one node is
received. When all frame data from the node is not received, all data sent from the node is discarded.
Node 01
㧦Area assigned to the node
Common memory
Data + token
Node 02
Node 03
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̖̖
̖̖
̖̖
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Node n
(Receive)
(Receive)
(Receive)
(Receive)
(Receive)
(Receive)
(Receive)
(Receive)
(Receive)
(Receive)
(Receive)
(Send)
(Send)
(Send)
(Send)
(Receive)
FL-net