704
SP.CONTSW
(b) If systems could not be switched due to any of the reasons given in the following table, the error completion device
turns ON when system switching is executed in the END processing.
When the error completion device was turned ON due to unsuccessful system switching, 16 is stored into the
"reason(s) for system switching (SD1588)" and the reason No. of the above table into the "reason(s) for system
switching failure (SD1589)".
(6) Use a user program or GX Developer to turn OFF the error completion bit that has turned ON.
If normal system switching is performed by the execution of the SP.CONTSW instruction with the error completion device
ON, the error completion device of the new standby system CPU module is also turned OFF.
When system switching is performed due to a factor other than the SP.CONTSW instruction, however, the error
completion device is not turned OFF.
Operat
i
on
E
rror
(1) In any of the following cases, an operation error occurs, the error flag (SM0) turns ON, and an error code is stored into
SD0.
(2) If system switching was unsuccessful, the error flag (SM0) is turned ON and an error code is stored into SD0.
Reason No.
Reasons for System Switching Failure
0
Normally completed
1
Tracking cable is disconnected or faulty.
2
Hardware fault, power-off, reset or watchdog timer error occurred in the
standby system.
3
Watchdog timer error occurred in the control system.
4
Preparations being made for tracking transfer.
5
Communication time-out.
6
Stop error occurred in the standby system. (Excluding watchdog timer error)
7
Operating status different between the control system and standby system.
8
Memory copy being executed from the control system to the standby system.
9
Write during RUN being executed.
10
Network fault detected by the standby system.
Error
code
Error details
Q00J/
Q00/
Q01
QnH
QnPH QnPRH
QnU
LCPU
4110
The value specified at is 0 at execution of the SP.CONTSW
instruction.
––
––
––
––
––
4120
The manual switching enable flag (SM1592) is OFF (disabled) at the
execution of the SP.CONTSW instruction.
––
––
––
––
––
4121
The SP.CONTSW instruction was executed by the standby system CPU
module in the separate mode.
The SP.CONTSW instruction was executed in the debug mode.
––
––
––
––
––
Error
code
Error details
Q00J/
Q00/
Q01
QnH
QnPH QnPRH
QnU
LCPU
6220
The tracking cable is disconnected or faulty.
Hardware fault, power-off, reset or watchdog timer error occurred in the
standby system.
Watchdog timer error occurred in the control system.
Preparations are being made for tracking transfer.
Communication time-out occurred.
A stop error, excluding watchdog timer error, occurred in the standby
system.
The operating status differs between the control system and standby
system.
Memory copy is being executed from the control system to the standby
system.
Writing during RUN
Network fault was detected by the standby system.
––
––
––
––
––
S