ProSoft Technology MVI69-FLN - Manual (Page 101)

Reference MVI69-FLN ♦ CompactLogix Platform
FA Control Network Communication Module
ProSoft Technology, Inc. Page 101 of 137
November 3, 2008
Transmission Cycle
With cyclic communications, the Common Memory is refreshed on a fixed cycle
time. Message communications are controlled so that the Common Memory
refresh time does not exceed the allowable refresh cycle time.
Each node constantly monitors the message communications frames that travel
through the network from the time it receives one local-node-directed token until
it receives the next local-node-directed token. When no message
communications frame travels through the network in a single cycle, 120% of the
cycle time value becomes the allowable refresh cycle time. In this way the
allowable refresh cycle time is actively determined according to the number of
nodes in the network.
Common memory is divided by each node not to be overlapped.
ƒ Share the same data in a system by each node's data broadcasting.
ƒ Data on the common memory is refreshed cyclically.
ƒ User can use the common memory as global area in the node.