Omron CJ1W-FLN22, Operation Manual, Page: 43 / 277

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FL-net Section 2-1
FL-net Protocol
FL-net consists of six protocol layers, as shown in the following diagram.
Note The transport and network layers use UDP/IP, whereas Ethernet is used as
the protocol for the data link and physical layers.
FL-net Transmission
Features FL-net's FA link protocol layer is characterized by the following features.
1,2,3... 1. Collisions are avoided by transmission control that uses the token method
that does not use a master.
2. The refresh cycle time can be regulated by fixing the cycle time of the to-
ken.
3. The designated token is transmitted together with cyclic data.
4. The token is transmitted first by the node that has the smallest number at
startup.
5. When no token is transmitted in a specified period of time, the next node
in the token rotation order sends a new token.
6. This token method prevents the network from stopping when there is a fail-
ure of only some of the nodes.
7. The information management tables provide useful information, such as
operation mode (RUN/STOP) and hardware malfunctions (ALARM), that
can be referenced to monitor the operating status of other nodes.
FL-net IP Addresses Unique class-C IP addresses must be assigned to each node in the FL-net
network.
An IP address is an address identifying each node (station) for transmission
using IP (internet protocol). Therefore, IP addresses must be set and man-
aged so that no two nodes have the same IP address. FL-net uses Class-C IP
addresses. The default IP address for FL-net is 192.168.250.***, with *** rep-
resenting the remote node number.
FL-net
Protocol
Application layer User application Interface
FA link protocol layer
Cyclic transmission
Message service
Message transmis-
sion
Token management
Transport layer UDP
Network layer IP
Data link layer Ethernet
(IEEE802.3 standard)
FL-net (Ver.
2.00) IP
address
Network address Host number
(node number)
192.168.250 n (n: 1 to 254)