6
6.2 Redundant System Network Overview
6.2.3 Ethernet
6
- 28
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
(1) Overview of Communication with External Devices
(a) Communication by MC Protocol, and Data Link Instructions
For MC protocol, external devices can communicate with the specified system,
i.e., control system, standby system, system A, or system B.
(b) Communication by Fixed Buffers and Random Access Buffers
For fixed buffers and random access buffers, external devices can communicate
with the control system Ethernet module only, as processing via sequence
programs is necessary.
(2) External Device Operation at System Switching
When system switching occurs in a redundant system, external devices operate
differently according to the communication method.
(a) In the case of OPS connection
When system switching occurs in a redundant system, the OPS automatically
switches the connection path, and continues the communication.
[Example]
Diagram 6.22 shows the external device operation when the control system
Ethernet module detects a communication error.
Diagram 6.22 Operation at Communication Error Detection
System A - Control System
Tracking cable
Tracking cable
System B - Standby System
OPS
System B - Standby System
System A - Control System
Communication
not possible
OPS
System switching request
Communications
error occurred
Normal
transmission