6
6.2 Redundant System Network Overview
6.2.2 MELSECNET/H Remote I/O network
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1
OV
ER
VIE
W
2
SYS
TEM
CONFIGURA
TI
ON
3
TR
AC
KI
N
G
C
ABL
E
4
P
R
OCE
DURE
FO
R
S
TAR
TING
UP
A
RE
DUN
DAN
T
S
Y
S
T
E
M
5
RE
DUNDA
NT S
Y
S
T
E
M
FUNCTIONS
6
RE
DUN
DAN
T
S
Y
S
T
E
M
NE
TW
O
R
K
S
7
PR
OG
R
A
MM
IN
G
CA
UTIO
N
S
8
TR
O
U
BLE
S
HOOTING
(b) Output Status during System Switching
The remote I/O station's output is held during system switching.
[Example]
Diagram 6.15 shows the redundant system when the control system network
module detects a communication error, on the assumption that the control system
network module is the master station, and the standby system network module is
the sub-master station.
Diagram 6.15 Output Status during System Switching
Control system
Standby system
Tracking cable
Tracking cable
MELSECNET/H Remote I/O network
Remote I/O station
(station No. 3)
Remote I/O station
(station No. 2)
Control
system
Standby
system
MELSECNET/H Remote I/O network
Remote I/O station
(station No. 3)
Remote I/O station
(station No. 2)
Output is preserved
during system switching
Output is preserved
during system switching
3) Perform system switching
2) Send a system switching request
1) Communication
not possible
Stop
Master
station
Multiplexed Remote Master
Station (station No. 0)
Multiplexed Remote Sub-master
Station (station No. 1)
Multiplexed Remote Master
Station (station No. 0)
Multiplexed Remote Sub-master
Station (station No. 1)
Standby
System
Control
System