Mitsubishi Electric MELSEC-A Series Manual page 29

1
INTRODUCTION
(e) 3-tier system 2: System configuration example using 2-tier local stations and 3-tier
remote I/O stations
MELSECNET/B
Twisted
M
L1 L2/m
r1
(f) 3-tier system 3: System configuration example using local stations/remote I/O stations
MELSECNET/B
Twisted
M
L1 L2/m
I1
MELSECNET/H
Optical loop
1N 1 Network 1 1N
S
2R1 Network 2 2R3
L3
Coaxial bus
1M 4
P
r2 r3
Network 1
1N 1
S
Network 2
2R1
MELSECNET/H
Optical loop
1N 1 Network 1 1N
S
1N
S
Network 2 Network 3
2N 1
S
2N
L3
Coaxial bus
1M 4
P
I2 r3
Network 1
1N 1 1N
S
Network 2
2N 1 2N
S S
System configuration precautions
1M 4
P
3
S
1N 2/2M
S R
New installation: The installation has to be
changed for an optical loop system or a
coaxial bus system.
A PLC to PLC network can be changed to a
2R2
twisted bus system, and a remote I/O
network can be changed to an optical loop or
coaxial bus system (refer to (c)).
1N 2/2M 1N 3
S R S
2R2 2R3
System configuration precautions
1) New installation: The installation has to
be changed for an optical loop system or
1M 4
a coaxial bus system.
P
A PLC to PLC network can be changed to
a twisted bus system, and a remote I/O
3
S
network can be changed to an optical
loop or coaxial bus system (refer to (c)).
2/2M 4/3M
P R
By processing the terminals, the existing
cables can be used for the twisted bus
3R3
system.
2
S
2) Composite system: As a mixture of a PLC
to PLC network and a remote I/O network
is not allowed on the Q series, the
network has to be divided into two
networks having different network Nos.
For this reason, a separate network
module for the remote master station is
2/2M 4/3M 1N 3
S P R S
required.
3) Wire-saving: Changing to a wire-saving
Network 3
network by using CC-Link or CC-Link/LT
is also recommended for remote I/O
2 3R3
stations.
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