Mitsubishi MELSEC Q Series Programming Manual page 919

(5) The error completion device is turned ON by the control system CPU module when system
switching by the SP.CONTSW instruction was unsuccessful.
(a) When OPERATION ERROR is detected due to any of the following reasons at the
execution of the SP.CONTSW instruction, the error completion device is turned ON
during the instruction execution.
• 0 is specified at
• The "manual switching enable flag (SM1592)" is OFF.
• The SP.CONTSW instruction was executed by the standby system in the separate
mode.
• The SP.CONTSW instruction was executed in the debug mode.
(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.
Reason No.
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.
Operation Error
(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.
• The value specified at
• The manual switching enable flag (SM1592) is OFF (disable) at execution of the
SP.CONTSW instruction.
• 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.
of the executed SP.CONTSW instruction.
S
0
Normally completed
1 Tracking cable is disconnected or faulty.
Hardware fault, power-off, reset or watchdog timer error occurred in the standby
2
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.
is 0 at execution of the SP.CONTSW instruction.
S
Reasons for System Switching Failure
SP.CONTSW
7
7
11
7
7
7
7
7
(Error code: 4100)
(Error code: 4120)
(Error code: 4121)
(Error code: 4121)
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