Operation Processing During Momentary Power Failure - Mitsubishi Electric L02SCPU User's Manual And Reference

2.5

Operation Processing During Momentary Power Failure

When the input voltage supplied to the power supply module drops below the specified range, the CPU module detects
a momentary power failure and performs the following operation.
(1) When a momentary power failure occurs for a period shorter than the
allowable power failure time
The CPU module registers error data and suspends the operation processing. The CPU module, however,
continues measurement in the timer device and holds the output status.
• When resume start is specified for the SFC program, data in the system is saved.
• The CPU module restarts its operation processing.
• Even if operation processing is suspended due to a momentary power failure, the CPU module continues the
measurement of the watchdog timer (WDT).
Ex.
When the WDT setting of PLC parameter is 200ms and the scan time is 190ms, if a momentary power
failure occurs for 15ms, "WDT ERROR" occurs.
(2) When a momentary power failure occurs for a period longer than the allowable
power failure time
The CPU module starts its operations initially and the operation processing will be the same as that when either
of the following is performed.
• Powering off and then on the CPU module
• Resetting the CPU module
50
Instantaneous power
Power recovery
failure occurred.
END 0 END 0
The CPU module suspends
its program operation.
END