Operation Processing During Momentary Power Failure - Mitsubishi Q-Series User Manual

4 SEQUENCE PROGRAM CONFIGURATION & EXECUTION
CONDITIONS

4.5 Operation Processing during Momentary Power Failure

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The Basic model QCPU detects a momentary power failure to the power module when
the input power voltage is lower than the regulated ranges.
When the Basic model QCPU detects a momentary power failure, the following
operation processing is performed:
(1) When momentary power failure occurs for less than permitted
power failure time
(a) The output is maintained when the momentary power failure occurs, and file
name of the file accessed and error history are logged. Then the system
interrupts the operation processing. (The timer clock continues.)
(b) When a momentary power failure ends, the operation processing is
resumed.
(c) Even if the operation is interrupted due to momentary power failure, the
watchdog timer (WDT) measurement continues. For example, if the GX
Developer PLC parameter mode WDT setting is set at 200 ms, when a
momentary failure of 15 ms occurs at scan time 190 ms, the watchdog
timer error is set.
Momentary power failure occurrence
Fig.4.5 Operation Processing When Momentary Power Failure Occurs
(2) When a power failure occurs for more than the permitted power
failure time
The Basic model QCPU starts initially. (PLC power is turned on.)
The same operation processing as that after the following operation occurs.
• Power ON
• Resetting using RUN/STOP/RESET switch
• Remote setting using GX Developer
Power recovery
END 0 END
QCPU interrupts the operation.
MELSEC-Q
END
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