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FL-net Overview Section 1-1
4
Supports Required Functions between FA Controllers
User-defined specifications allow the following range of features that are
required for FA systems.
1. Large-scale network
Up to 254 devices (nodes) can be connected in the physical layer of the
network.
2. Dual communications functions to suit application
The Common Memory function uses cyclic transmission so that each node
can always share the same data with other nodes on the network. FL-net
also supports message communications for use when handling only es-
sential data is required.
3. Large-capacity Common Memory
The Common Memory is provided with a large capacity of 8 Kbits and 8
Kwords.
4. High-speed response
High-speed response time of 50 ms/32 nodes (for 2 Kbits and 2 Kwords)
is provided.
The absence of a master in the FL-net network enables nodes to be added
or removed readily without affecting any other nodes. This allows any node
to be turned ON or OFF easily and facilitates maintenance.
General Differences between Ethernet and FL-net
1. FL-net is a network designed for FA environments and is not compatible
with all general-purpose Ethernet devices. Some devices are not suitable
due to noise resistance and environment resistance requirements.
2. Only FL-net-compatible controllers and control devices can be connected
to FL-net to meet the demands of control applications requiring respon-
siveness in realtime communications.
3. FL-net is a cyclic communications method using the broadcasting support-
ed by UDP/IP protocols based on the 10Base-5 and 10Base-T standards.
The following restrictions currently apply.
• Compatible devices mainly use 10 Mbps Ethernet LAN.
• Connection to other general-purpose Ethernet systems is not supported.
• TCP/IP are not supported.
• Switching hubs cannot be used effectively.
• Routers and similar devices may not be compatible.
FL-net FAQ
Question Answer
1 What is Ethernet? Ethernet is a standard defining a type of cable. It is used in a local area network (LAN). An
Ethernet network transmits data between computers at a baud rate of between 10 Mbps and
100 Mbps. Currently, the most commonly used Ethernet in offices and other OA systems is
twisted-pair cable (UTP) that uses 10 Mbps. Ethernet communications are possible using
software protocols provided by many vendors.
2 What is FL-net? The FL-net is a network to which programmable controllers (PLCs), computerized numeric
controllers (CNCs), and other FA controllers are connected, and on which control data is
exchanged between controllers at high speed. FL-net uses the same cables that are used for
Ethernet.