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26 REDUNDANT FUNCTION
26 REDUNDANT FUNCTION
This chapter describes the redundant system functions.
Function Description Reference
Operation mode change Switches the operation mode of the redundant system between the backup
mode for normal operation and the separate mode for system maintenance
while it is running.
Page 371 Operation Mode
Change
System switching Switches the systems between the control system and the standby system
to continue operation of the redundant system when a failure or an error
occurs in the control system. For debugging and maintenance purpose,
users can switch the systems at any desired timing.
Page 374 System Switching
Tracking transfer Transfers the control data from the control system to the standby system
and maintains the consistency of the data in the two systems to continue
operation of the redundant system when a failure or an error occurs in the
control system.
Page 388 Tracking Transfer
Memory copy from control system to
standby system
Transfers data such as parameters and programs in the CPU module of the
control system to the CPU module of the standby system to maintain the
consistency of the memory in the two CPU modules.
Page 405 Memory Copy from
Control System to Standby
System
System consistency check Checks whether the system configurations and files in the CPU modules
are the same between the control system and the standby system when the
redundant system is in backup mode.
Page 413 System Consistency
Check
Program execution in both systems Detects an error in the external device or network of the systems (control
system and standby system) by executing a program that diagnoses
external devices or networks of both systems.
Page 418 Program Execution in
Both Systems
Redundant system operation setting Set the redundant system operation in the redundant system settings of the
CPU parameter.
Page 425 Redundant System
Operation Setting
Redundant function module communication
test
Checks the redundant function module itself for errors when its
communications are unstable.
Page 428 Redundant Function
Module Communication Test
Redundant system
with redundant
extension base unit
Settings for
redundant system
with redundant
extension base unit
Set the operation of the redundant system with redundant extension base
unit in the redundant system settings of the CPU parameter.
Page 429 Settings for Redundant
System with Redundant
Extension Base Unit
Automatic standby
system recovery
Allows the CPU module of the standby system to automatically recover from
a specific error that occurs in the CPU module of the standby system.
(Manual operation (turning off and on or resetting the system) is not
required to recover the system.)
Page 430 Automatic recovery of
the CPU module of the standby
system
Replacement/
addition of an
extension cable
(online)
The extension cable on the inactive side (ACTIVE LED is turned off)
between the redundant extension base units can be replaced or added
while the system is running.
Page 548 Replacement/Addition
of Extension Cables (Online)
SLMP communications • There are notes for system switching when the system IP address
matching function is not used.
• When a remote operation command is executed, an operating status
mismatch occurs between the CPU modules and the system switching is
disabled.
• In SLMP communications via the built-in Ethernet port of the CPU
module, when communications are performed to the other system that
cannot respond (power-off, reset, or tracking cable disconnection), a
timeout error may occur.
• The SLMP frame send instruction (SP.SLMPSND) performs
communications using different IP addresses in the system A and the
system B.
Page 432 SLMP Communication
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