Cases In Which Routing Tables Are Required - Omron CJ2 CPU - REV 10-2010 User Manual

4-4-2 Cases in Which Routing Tables Are Required

Set the routing tables (local network table and relay network table) in the CPU Unit as required by the
application.
Precautions for Correct Use Precautions for Correct Use
Conditions Required for a Local Network Table
A local network table is required if there is more than one Network Communications Unit con-
nected in the PLC even when relaying is not performed.
The following table shows whether routing tables are required or not according to the network usage
conditions.
Network usage
condition
A Network Communi-
cations Unit is not
connected in the PLC
or only a Network
Communications Unit
classified as a Spe-
cial I/O Unit (e.g.,
CompoNet) is con-
*1
nected.
More than one Com-
munications Unit clas-
sified as CPU Bus
Units is connected in
the PLC.
*1 Set the remote network address to 0 if a node in the network will be accessed using a Programming Device.
*2 If there is no local network table and access is made with the network address set to 0 using a Programming
Device or an instruction in a ladder program, the network with the Network Communications Unit with the low-
est unit number will be accessed automatically in FINS communications. In this way, the network can be
accessed by setting the lowest unit number for the Network Communications Unit in the network to be
accessed without setting local network tables.
*3 Relay network tables do not need to be set if communications will not be performed across network layers.
CJ2 CPU Unit Software User's Manual
System configuration
CX-Programmer
Only Network Communications Units
classified as Special I/O Units
Local PLC
Message
communications
Communi-
cations
instruction
One network = Local network
Network address = 0
CX-Programmer
It is necessary to specify which of the Network
Communication Units to pass through.
Local PLC
Message
communications
Communi-
cations
instruction
4 CPU Unit Initialization
Routing tables
Local net-
work table
Not required
CompoNet
Required for
all PLCs in
the net-
*2
works
Multiple
networks
Set more
than one
network
address.
Relay net-
work table
Not required
4
Required if
communica-
tions will be
performed
across net-
work layers.
*3
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