Omron CJ Series, Operation Manual

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3-1 Routing Table Overview
3-1-1 Definition of Routing Tables
3-2
3-1 Routing Table Overview
3-1-1 Definition of Routing Tables
The routing tables register the paths to destination networks and the addresses for the
nodes in FINS communications. The routing tables are required when transferring
data between networks by message communications or other functions, or switching
the destination PLC in the network accessed from a Programming Device or ladder
program instruction.
Set the routing tables in the PLCs as required. Refer to
3-1-2 Network Conditions That
Require Routing Tables for details on the cases when routing tables are required.
Routing tables consist of the following two tables.
1) Local network table
When two or more Communications Units are mounted in a single PLC, the CPU
Unit uses the local network table to identify the Communications Units and
associated networks.
The local network table is required when two or more Communications Units are
mounted in a single PLC, or data will be transferred across network levels.
2) Relay network table
When transferring data between networks, the relay network table indicates how
to relay a received message to reach the final destination node.
The relay network table is required when data will be transferred across network
levels.
Local Network Table
The local network table lists the unit numbers of the Communications Units mounted
in each PLC, and the network addresses of the connected networks. When data is
being transferred from the PLC to a destination network address, the local network
table indicates which Communications Unit can be used to send data to the
destination network address.
The local network table is stored in the CPU Unit, and it is possible to switch the
destination network first accessed from a Programming Device or ladder program
instruction.
Unit Number
This value (0 to 15) is set with the rotary switches on the front of each
Communications Unit
Network Address
•
Sets the network address (1 to 127) of the network to which each
Communications Unit is connected.
•
The network address must be greater than zero. (See note.)
Note: Setting a network address of 0 indicates to the computer that a local network table is not
set in the PLC.
In this manual, network address 0 is called the local network address.
Network address 3
Network address 2
Network address 1
Unit number 00
Unit number 01
Unit number 02
Example Local Network Table
Unit number Local network address
00 1
01 2
02 3