ProSoft Technology MVI69-FLN - Manual (Page 79)

Reference MVI69-FLN ♦ CompactLogix Platform
FA Control Network Communication Module
ProSoft Technology, Inc. Page 79 of 137
November 3, 2008
Cyclic Transmission Function
Cyclic transmission means a function that supports cyclic data exchange
between nodes.
Basic functions
1 The cyclic transmission implements common memory interface.
2 Each node sends its whole data while it holds the token.
3 Nodes having no cyclic data are acceptable.
Common memory
1 The common memory interface provides nodes with a service that can be
regarded as a memory shared among them.
2 Two area types (Area 1 and Area 2) may be assigned for a node.
3 Multiple frames may be used if the transmitting area size of a node exceeds
the transmission size of one frame, that is, 1024 bytes.
4 The common memory will not update itself with receiving data until all frames
from a node are successfully received in case of the item (3).Thus time
coherency of data from a node is guaranteed.
5 Communication unit of each node shall provide fixed area of 8k bits + 8k
words = 8.5k words as the common memory.
6 Both Area 1 and Area 2 can be set at any size within the maximum.
Data Share Function
Each node on a FL-net has specific transmission area in the common memory
that does not overlap with others. A transmission area assigned to one node
must be receiving area for other nodes.
Each node broadcasts its data in a fixed cycle and all the nodes in a network
share the same data on the common memory.