5
REDUNDANT SYSTEM FUNCTIONS
5.3 The System Switching Function
5.3.1 System Switching Method
5 - 40
1
OVERVIEW
2
SYSTEM
CONFIGURATION
3
TRACKING CABLE
4
PROCEDURE FOR
STARTING UP A
REDUNDANT SYSTEM
5
REDUNDANT SYSTEM
FUNCTIONS
6
REDUNDANT SYSTEM
NETWORKS
7
PROGRAMMING
CAUTIONS
8
TROUBLESHOOTING
POINT
1. Precautions When Executing the System Switching Instruction (SP.CONTSW
instruction)
As the control system and standby system CPU module programs and device
data are consistent, when the system switching instruction is executed in the
control system CPU module, the system switching may be executed in the
new control system CPU module, too.
When executing the system switching instruction, it is required to use the
special relay "Standby system to control system switching status flag
(SM1518)" as illustrated in Diagram 5.29, and modify the program so that the
instruction will not be executed in the new control system CPU module again.
2. The error completion device for the system switching instruction can be used
to check whether system switching is executed by the system switching
instruction or not.
• When the error completion device is OFF . .System switching is
executed
• When the error completion device is ON . . .System switching is not
executed
Diagram 5.29 Program That Does Not Execute System Switching Instruction Again
in New Control System CPU Module
SET M0
Standby system to control system
switching status flag
SM1518
RST M0
Cancel Signal
M1001
SP.CONTSW K1 M10
*1
system switching command
M1000
M0
*1 : When the SP.CONTSW instruction
cannot perform a system switch,
the error completion device (M10)
is set to ON.
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