Data Link Overview; Fl-Net Cyclic Transmission And Common Memory - Omron CS1W-FLN22 Operation Manual

Data Link Overview

5-1 Data Link Overview
5-1-1

FL-net Cyclic Transmission and Common Memory

64
The data link function uses FL-net cyclic transmission for automatically
exchanging data, from preset areas, between nodes on a single network
(between two PLCs or between a PLC and an FA computer). The CS1W-
FLN22/CJ1W-FLN22 can also be used for exchanging data between CS/CJ-
series PLCs or between FL-net nodes by other manufacturers.
1. Cyclic Transmission Overview
Cyclic transmission supports the exchange of cyclic data between nodes.
a) Cyclic transmission uses Common Memory as an interface.
b) When a node is holding the token the node transmits cyclic data.
c) Not all nodes participating in the network must support cyclic transmis-
sion.
d) The node holding the token transmits all cyclic data that should be
sent.
Time
Node #1
Node #2
Token
Node #2
Node #1
Node #1
Node #2
Node #1
Node #2
Token: There is basically only one token in a network. If more than one token
exists in a network, the token whose destination node has the smallest node
number will be given priority and the other tokens will be discarded.
Token frame: the token frame is a frame that includes the token. It consists of
the token's destination node number and source node number. Each node
becomes the token holding node when its node number matches the token
destination node number in the received token frame.
Token flow: The token rotation order is determined by the node numbers.
Each node circulates the token among the nodes registered in the participat-
Node #3
Node #3
Token
Node #N-1
Node #N-1
Token
Section 5-1
Node #N
Node #N
Node #N
Token
Node #N