Mitsubishi Electric MELSEC Q Series User Manual page 19

Precautions for battery
Precautions for use of CompactFlash card
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In any of the following cases, erasure of data (e.g. logging data) being processed,
corruption of data in the standard ROM drive/CompactFlash card during access, or a
file system fault may occur. ( )
1) When the battery is not replaced after battery error occurrence (Refer to Section
4.10.3)
2) When shut-down operation is not performed before power off during operation
without battery (Refer to Section 4.11)
3) When the battery is removed without shut-down operation being performed (Refer
to Section 4.12)
It is recommended to back up the standard ROM data (setting information,
logging data, user HTML, etc.) to the CompactFlash card periodically in case of
corruption of data in the standard ROM drive. (Refer to Section 6.10)
(1) Available CompactFlash cards
Use a CompactFlash card listed in Section 2.4. (Refer to Section 2.4.)
Failure to do so may cause a problem such as data corruption in the
CompactFlash card and system stop.
(2) When powering off the system or resetting the CPU module
When the system is powered off or the CPU module is reset during writing to the
CompactFlash card, the write processing may not be completed.
In this case, the Web server module can normally be powered off without file
access stop because it automatically restores the files when powered on again.
In rare cases, however, the module cannot completely restore files.
If a problem arises by this, perform file access stop processing before powering
off the system or resetting the CPU module.
Also, regularly backing up important data (e.g. save on other media) is
recommended. (Refer to Section 4.9.2 (1).)
(3) Removal or replacement of CompactFlash card
(a) Be sure to stop file access before removing or replacing the CompactFlash
card. (Refer to Section 4.9.2.)
(b) Failure to observe the procedures indicated in Section 4.9.2 may result in
erasure of logging data during processing, corruption of data in the
CompactFlash card during access, or a file system fault.
(c) If a CompactFlash card fault has occurred, refer to Section 9.1 (9) and
restore the card.
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