Omron CS1W-FLN22 Operation Manual page 31

FL-net Overview
Question
3 What is the differ-
ence between FL-
net and Ethernet?
4 How are FL-net
Units used?
5 What does "proto-
col" mean and what
protocols does FL-
net support?
6 Can FL-net be con-
nected to a stan-
dard personal
computer?
7 What does "topol-
ogy" mean?
8 What type and
length of network
cables are used,
and how many Units
can be connected?
9 Do systems using
FL-net require spe-
cial Ethernet specifi-
cations?
10 How do you connect
to FL-net?
11 What type of cables
should be used
when configuring an
FL-net system?
12 How is the FL-net IP
address set?
13 How compatible and
inter-connectable
are devices that
support FL-net?
With Ethernet, the host computer, personal computers, and controllers are connected to the
network for data exchange and control applications, such as executing production instructions
and compiling results. The FL-net is used to connect controllers together and allow high-
speed control data exchange.
Be sure to connect cables properly when installing both Ethernet for communications with the
host and FL-net for communications between controllers for the same controllers.
FL-net Units are installed in FA controllers, such as programmable controllers (PLCs) and
computerized numeric controllers (CNCs). By simply setting link allocations for the local node
address (node number) and Common Memory (also called link registers), FL-net Units trans-
mit data between controllers cyclically in the same way as CPU Link Units in standard PLCs.
This method does not require special communications programs for the PLC and other Units
on the network. Such programs are also not required by the PLC for operations conducted via
the personal computer, including reading or writing data, such as the PLC memory or commu-
nications parameters. Separate programs are required for each controller, however, when
transmitting data between controllers using message communications.
Protocol refers to rules for communications. The protocols supported by FL-net are UDP/IP
and FA Link Protocol. (The FA Link Protocol is located in the layer above UDP/IP and is a spe-
cial protocol for use on FL-net networks.)
The FL-net Unit, which is mounted to FA controllers such as programmable controllers (PLCs)
and computerized numeric controllers (CNCs), is an intelligent unit with a processor on its
board. The Ethernet Card in the personal computer is a non-intelligent format called a "dumb
board," so its capacity depends on the performance and functions of the personal computer.
Generally, an intelligent FL-net board is recommended.
Networking topology refers to the wiring formation of the network. The three main formations
are star (or tree), bus, and ring. Rather than physical wiring formations, however, it is easier to
understand them as theoretical formations. An FL-net system has star topology when using
10Base-T cables and bus topology when using 10Base-5 cables.
The most commonly used Ethernet cable standards and some of their characteristics and lim-
itations are listed below. The figures in parentheses are applicable when repeaters are used.
• 10Base-T: Twisted-pair cables (UTP), maximum transmission distance is 100 m (500 m)
per segment, maximum number of Units is 254 per segment.
• 10Base-5: Thick coaxial cables (yellow cables), maximum transmission distance is 500 m
(2,500 m) per segment, and maximum number of Units that can be connected is 100
(254) per segment.
• 10Base-FL: Optic fiber cable, maximum transmission distance is 2,000 m per segment,
and maximum number of Units that can be connected is 254 per segment.
No. FL-net systems are configured using Ethernet (conforming to the IEEE802.3 standard).
Special specifications are not required.
Ethernet cables for different types of Ethernet media can be connected to each other using
repeaters, media adapters, and other devices. These products are available from many ven-
dors.
In general, use the following cables.
• Basic wiring: 10Base-5 Thick coaxial cables; yellow cables.
• In the control panel and in offices: 10Base-T twisted-pair cables; UTP category 5.
• High-voltage wiring and noise-prone environments: 10Base-FL optic-fiber cables.
The FL-net IP address is set as follows:
Network address: 192.168.250
Host number (node number): 1 to 254 is standard. Nodes 250 to 254, however, are reserved
for maintenance devices.
FL-net has a certification system whereby compatibility and inter-connectivity tests are per-
formed.
Certification documents are provided for those devices that pass the tests, so devices sup-
porting FL-net can be used safely on the network.
Answer
Section 1-1
5