APPX
Appendix 4 List of Special Relay Areas
665
A
Redundant function
The following is the list of special relay areas relating to the Redundant function.
No. Name Data stored Details Set by (setting
timing)
SM1630 Operation mode
identification flag
Off: Redundant system in backup mode,
stand-alone system
On: Redundant system in separate mode
This relay turns on while a redundant system is
operating in separate mode.
S (Every END)
SM1632 System A
identification flag
Off: System B, system not determined
On: System A
• This relay distinguishes between the system A and
the system B.
• The flag status does not change even if tracking
cables are disconnected.
S (Initial)
SM1633 System B
identification flag
Off: System A, system not determined
On: System B
• This relay distinguishes between the system A and
the system B.
• The flag status does not change even if tracking
cables are disconnected.
S (Initial)
SM1634 Control system
judgment flag
Off: Standby system, system not
determined
On: Control system
• This relay indicates operating status of the CPU
module. The flag is stored in each system when an
initial processing is performed (including when the
system is determined while waiting for the start-up
of the other system) and when a system switching is
completed.
• The flag status does not change even if tracking
cables are disconnected.
S (Initial/Status
change)
SM1635 Standby system
judgment flag
Off: Control system, system not
determined
On: Standby system
• This relay indicates operating status of the CPU
module. The flag is stored in each system when an
initial processing is performed (including when the
system is determined while waiting for the start-up
of the other system) and when a system switching is
completed.
• The flag status does not change even if tracking
cables are disconnected.
S (Initial/Status
change)
SM1636 Previous control
system identification
flag
When the previous control system is the system B, this
relay turns on during one scan in the system A,
following the RUN state after both systems were
powered on or the CPU module is reset.
S (Every END)
SM1637 System switching
detection (standby
system to control
system)
Off: Not detected
On: Detected
This relay turns on after the standby system has been
switched to the control system.
S (Status change)
SM1643 ON for only one scan
after system
switching (standby
system to control
system)
• This relay turns on during one scan after the
standby system was switched to the control system.
• This relay can be executed only in a scan execution
type program.
S (Every END)
SM1644 ON for only one scan
after system
switching (control
system to standby
system)
• This relay turns on during one scan after the control
system was switched to the standby system.
• This relay can be executed only in a scan execution
type program.
S (Every END)
SM1645 System switching
request from a
network module
Off: System switching request not issued
On: System switching request issued
• This relay turns on when a system switching request
from a network module is issued.
• The module that issued system switching can be
checked in SD1645.
• This relay turns off when all bits of SD1645 are off.
S (Every END)
SM1646 System switching by
a user
Off: Disabled
On: Enabled
•
T
his relay stores whether to enable system
switching operation by a user using an engineering
tool or the SP.CONTSW instruction.
• Initial value is off: System switching by a user is
prohibited.
U
SM1653 Memory copy start Off: Not started
On: Start
• When this relay is turned from off to on, the memory
copy from the control system to the standby system
starts. Note that the memory copy does not start as
long as the I/O number of the copy destination
(standby system CPU module: 03D1H) is not stored
when SM1653 is turned from off to on.
• Initial value is off: The memory copy has not started.
U
ON
OFF
1 scan
ON
OFF
1 scan
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