Mitsubishi Electric Q172CPU, Programming Manual

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1 OVERVIEW
(a) When a CPU DOWN error occurs in the CPU of the CPU in a checked "Stop
all CPUs upon error in CPU No. n" item, all PLC CPU/Q173CPU(N)/
Q172CPU(N) of the other CPUs will generate a MULTI CPU DOWN error
(error code: 7000) and the Multiple CPU system will stop.
(Note-1)
(b) When a CPU DOWN error occurs in the CPU of the PLC in an unchecked
"Stop all CPUs upon error in CPU No. n" item, all CPUs of the other CPUs
will generate a MULTI CPU ERROR (error code: 7020) and continue their
operation.
POINT
(Note-1) : When a CPU DOWN error occurs, the CPU detecting the error will generate a
MULTI CPU DOWN error.
Therefore, the system may enter a MULTI CPU DOWN mode after detecting the
CPU DOWN error in the CPU generating a MULTI CPU DOWN error, instead of
the error in the CPU that generated the CPU DOWN error in the first place.
In this case, the common error-data area may store a CPU number different
from one corresponding to the CPU that generated the CPU DOWN error first.
When recovering the system, remove the cause of the error present in the CPU
not stopped by a MULTI CPU DOWN error.
In the screen below, the cause of the error present in CPU No.2, which does not
have a MULTI CPU DOWN error, should be removed.