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Behavior of sequence program in event of momentary power failure in LCPU
What status do sequence programs become in case of momentary power failure?
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Answer
(1) When it happened no longer than the allowable momentary power failure time.
The module records an error log and suspends the operation processing.
However, measurement in the timer device is continued. Also, the output status is held.
- When resume start is specified for the SFC program, data in the system is saved.
- When the power is recovered from the momentary failure, the module resumes the operation processing.
- Even if operation processing is suspended due to a momentary power failure, the measurement of the watchdog timer
(WDT) is continued.
(2) When it happened longer than the allowable momentary power failure time.
The CPU module performs an initial start.The operation processing is the same as the following.
- Turning the power OFF then ON
- Resetting
The module records an error log and suspends the operation processing.
However, measurement in the timer device is continued. Also, the output status is held.
- When resume start is specified for the SFC program, data in the system is saved.
- When the power is recovered from the momentary failure, the module resumes the operation processing.
- Even if operation processing is suspended due to a momentary power failure, the measurement of the watchdog timer
(WDT) is continued.
(2) When it happened longer than the allowable momentary power failure time.
The CPU module performs an initial start.The operation processing is the same as the following.
- Turning the power OFF then ON
- Resetting
- Product Name
- MELSEC-L Series
- Series
- CPU
