Mitsubishi Electric MELSEC-Q00U(J)CPU User Manual page 259

(5) Deleting backup data
The backup data can be deleted in the following screen. (Stop the CPU module before deleting the backup data.
This operation cannot be performed when the CPU module is in the RUN status.)
[Online]
Also, information of special registers (SD671 to SD675) can be initialized (cleared to 0) by deleting the backup
data.
(6) Checking the status in the special relay and special register
The execution status of the function and the restoration operation status can be checked in SM671, SM676, and
SD671 to SD679. For details, refer to the following.
QCPU User's Manual (Hardware Design, Maintenance and Inspection)
(7) Precautions
The following provides precautions for backing up latch data.
• Do not power off or reset the CPU module during backup of latch data. If performed, "RESTORE ERROR"
(error code: 2221) occurs, and the backup data is not restored. (The backup data will be deleted.)
• Even if the backup data exists, the initial device value has a priority over the backup data when the initial
device value is set. Therefore, the device where the initial device value setting is configured is overwritten by
the device data of the initial device value after reflecting the backup data.
• Even if the latch device or latch range setting is used, backup data has a priority. Therefore, even when data
of latch device and latch range setting are changed after backup, it is overwritten by data backed up when
the CPU module is powered off and then on or is reset.
• Devices where local device range setting is configured are not backed up. They are initialized (cleared to 0)
when the CPU module is powered off and then on or is reset.
• When the number of writes to the standard ROM exceeds 100,000 times ("FLASH ROM ERROR" (error
code: 1610) is detected), data may not be normally backed up.
• Backup data cannot be deleted unless the data are deleted or the storage location memory (standard ROM)
for the backup data is formatted.
• The following operations cannot be performed during latch data backup. Perform them after the backup
operation. If performed, an error is displayed on the programming tool.
• Format PLC memory (standard ROM only)
• Latch data backup by remote operation
• Online change (ladder mode, files, function block)
• Program Memory Batch Download
• Write to PLC (Flash ROM)
• CPU module change function with memory card
• CPU module data backup/restoration function
• When the High-speed Universal model QCPU and Universal model Process CPU are used and the "Backup
all files in the internal of standard RAM" checkbox is checked in parameter, "RESTORE ERROR" (error
code: 2228) occurs if the size of the standard RAM is smaller than the backup data.
[Latch Data Backup] [Delete Backup Data]
CHAPTER 3 FUNCTIONS
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