Mitsubishi Electric Q01UCPU User Manual page 284

(3) Automatic backup using SD910
The data of CPU module is automatically backed up by an execution timing which is set in advance.
The execution timing of the automatic backup is set with SD910 (Backup function setting). Multiple execution
timing can be set simultaneously.
Bit pattern of SD910
Bit0: On
Bit1: On
Bit15: On
Since the special register set for the automatic backup is in latch area, the set data are hold.
(a) Retry of the automatic backup
Set whether to retry the automatic backup in the case the automatic backup is executed while any of the
exclusive functions (refer to Page 286, Section 3.32.1 (5) (i)) are being executed.
The retry is executed every three minutes and repeated 10 times.
Special relay/special register
SM924
SM1931
Bit10 of SD910
*1 Modules whose serial number (first five digits) is "18052" or earlier cannot use this setting. (The automatic backup
cannot be executed while any of the exclusive functions are executed.)
To reflect the setting of the following special relay and special register areas, which are set before starting
backup, in backup operation, turn off and on bit0, bit1, or bit15 of SD910.
When the following special relay and special register areas are changed while a backup is being executed,
value in bit0 of SD910 is reflected next time a backup is executed.
• Bit0 of SD910 (When bit0, bit1, or bit15 of SD910 is turned off and on)
• SD912 (When bit0 of SD910 is turned off and on)
• SD913 (When bit0 of SD910 is turned off and on)
• SD914 (When bit1 of SD910 is turned off and on)
• SD915 (When bit1 of SD910 is turned off and on)
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At the time set to SD913 on the day set to SD912
At the time set to SD914 on the day of the week set to SD915
When a CPU stop error has occurred
This relay turns on when the retry of the automatic backup is failed even after the specified number
of retries are attempted. (This relay turns off at the start of the automatic backup. (This relay does
not turn off when SM1926 (Backup execution request) is on.))
• Off: Retry not executed/Retry being executed
• On: Retry failed
This relay turns on while the retry is being executed. (This relay turns on at the start of the retry,
and turns off when the automatic backup is triggered by the retry while the exclusive functions are
not executed, or when the specified number of retries are attempted.)
• Off: Retry not performed
• On: Retry being performed
Set whether to retry the automatic backup with this bit.
• Off: No retry (The automatic backup will be completed with an error without a retry.)
• On: Retry
Execution timing
*1
Description