Mitsubishi Electric L02SCPU User's Manual And Reference page 180

(4) Precautions
(a) Power-off and reset of the CPU module during backup
The backup data are deleted. Performing power-off of reset of the CPU module causes "RESTORE ERROR"
(error code: 2221) and data cannot be restored.
(b) Priority of backup data
• When the device initial value has been set, it takes effect. (Therefore, after reflecting the backup data, the
device where the initial device value setting is configured is overwritten by the device data of the initial
device value.)
• When the latch device or latch range has been set, the backup data take effect. (Therefore, even if data of
latch device or latch range setting are changed after backup, it is overwritten by the data backed up when
the CPU module was powered off and then on or was reset.)
(c) When using a local device
Devices where local device range setting is configured are not backed up.
(d) The number of writes to standard ROM
The number of writes to standard ROM ("FLASH ROM ERROR" (error code: 1610) is detected), data may not
be normally backed up.
(e) Operations disabled during backup
The following operations cannot be performed during backup. Perform them after the backup operation.
• Format PLC memory (standard ROM only)
• Latch data backup by remote operation
• Online change (ladder mode, files, function block)
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