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19 DATA LOGGING FUNCTION
19.7 SD Memory Card Life and Replacement
SD memory card replacement
SD memory cards can be replaced using the SD memory card forced disable function even while data logging is in progress.
(Page 229 SD Memory Card Forced Stop) This function works by disabling data writes to the SD memory card while
allowing data collection to continue. (Data collection continues in accordance with the settings registered when data logging is
started.)
If SD memory card replacement causes processing overflow, make adjustments by changing the collection
interval, internal buffer capacity, or other settings.
Operation during SD memory card replacement
Mounting the replaced SD memory card on the CPU module causes a "LOGGING" folder to be created. When becoming
ready for running the logging function, the CPU module resumes the data transfer into the SD memory card.
The CPU module operates differently as follows depending on the folder configuration in the replaced SD memory card.
If the internal buffer becomes full during the time between SD memory card replacement and the resumption of data writes to
the SD memory card, processing overflow occurs resulting in missing data.
Storage file numbers after SD memory card replacement
The numbering of the first storage file created after SD memory card replacement differs depending on the storage file
switching condition, as described in the following table.
If the new SD memory card contains a "LOGGING" and "LOGGING_OLD" folder, data logging cannot be
executed. Ensure that the new SD memory card does not contain a "LOGGING" and "LOGGING_OLD" folder.
Logging state during SD memory card replacement
SD memory cards can be replaced without depending on the current data logging state.
Operations during SD memory card replacement
If one of the following operations is performed during the time between the removal and installation of SD memory cards, any
data collected during that time will not be stored in the new SD memory card.
• Stop and run
*1
• Power off and on
*1
• Reset
*1
• Suspend data logging
• Stop data logging
*1 An error is generated if data logging was previously running based on the setting file contained in the replaced SD memory card.
Folder constitution Operation of after SD memory card replacement
The folder not exist. LOGGING folder is made.
Only LOGGING folder • LOGGING folder is renamed by LOGGING_OLD.
• LOGGING folder is made.
Only LOGGING_OLD folder LOGGING folder is made.
LOGGING folder
LOGGING_OLD folder
Data logging state changes to error state.
Storage file switching condition Storage file numbers after SD memory card replacement
Overwrite Numbering continues from the number of the last storage file contained in the
replaced SD memory card.
Stop Numbering begins at 00000001.
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