Operation Processing At Momentary Power Failure - Mitsubishi Electric MELSEC iQ-R C R12CCPU-V User Manual

2.2

Operation Processing at Momentary Power Failure

When the input power voltage fed to the power supply module is lower than the specified range, a C Controller module detects
a momentary power failure and performs the following processes.
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When a momentary power failure less than the allowable time has occurred
When a momentary power failure occurs, a C Controller module suspends processing with its output status retained.
After power is recovered, error information is registered to the event history file. (Only at the first detection)
■When the momentary power failure is recovered
After the momentary power failure is recovered, a C Controller module continues processing.
■Check for the number of momentary power failure detection
Since a C Controller module retains number of momentary power failure inside the module, it can be checked using the
special register SD53 or the C Controller module dedicated function (CCPU_GetPowerStatus).
■Measurement of the watchdog timer (WDT) during a momentary power failure
A C Controller module continues measuring watchdog timer if the operation is stopped due to the momentary power failure.
For example, if a momentary power failure of 15 ms has occurred when the fixed cycle processing time is 190 ms while the
monitoring time of the system watchdog time is set to 200 ms, a watchdog timer error occurs.
When a power failure longer than the allowable time has occurred
The initial start is performed and the operation processing will be the same as when the powered ON or reset the C Controller
module.
2 OPERATION PROCESSING IN C Controller Module
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2.2 Operation Processing at Momentary Power Failure