2 Instruction Descriptions
2-858
NJ-series Instructions Reference Manual (W502)
The root directory of the file name is the top level of the SD Memory Card.
• Execution of this instruction is continued until processing is completed even if the value of Execute
changes to FALSE or the execution time exceeds the task period. The value of Done changes to
TRUE when processing is completed. Use this to confirm normal completion of processing.
• Refer to Using this Section on page 2-2 for a timing chart for Execute, Done, Busy, and Error.
• If a file is open when the operating mode of the CPU Unit is changed to PROGRAM mode or when a
major fault level Controller error occurs, the file is closed by the system. Any read/write operations
that are in progress are completed to the end.
• If a file is open when the power supply it stopped with the power switch, the file is not corrupted.
• If a file is open and the SD Memory Card is removed before the power switch is pressed, the contents
of the file will sometimes be corrupted. Always turn OFF the power supply before removing the SD
Memory Card.
• If a file is open when the power supply is stopped or the SD Memory Card is removed, it will not be
possible to read or write the file even if the SD Memory Card is inserted again.
• An error occurs in the following cases. Error will change to TRUE.
• The SD Memory Card is not in a usable condition.
• The SD Memory Card is write protected.
Related System-defined Variables
Name Meaning Data type Description
_Card1Ready SD Memory Card
Ready Flag
BOOL This flag indicates if the SD Memory Card is physi-
cally inserted and is mounted normally, i.e., if it can be
accessed by instructions and communications com-
mands.
TRUE: Can be used.
FALSE: Cannot be used.
_Card1Protect SD Memory Card Write
Protected Flag
BOOL This flag indicates if the SD Memory Card is write pro-
tected when it is inserted and ready to use.
TRUE: Write protected.
FALSE: Not write protected.
_Card1Err SD Memory Card Error
Flag
BOOL This flag indicates if an unspecified SD Memory Card
(e.g., an SDHC card) is mounted or if the format is
incorrect (i.e., not FAT16 or corrupted).
TRUE: Error.
FALSE: No error.
_Card1Access SD Memory Card
Access Flag
BOOL This flag indicates if the SD Memory Card is currently
being accessed.
TRUE: Being accessed.
FALSE: Not being accessed.
_Card1PowerFail SD Memory Card
Power Interruption Flag
BOOL This flag indicates if an error occurred in completing
processing when power was interrupted during SD
Memory Card access. This flag is not cleared auto-
matically.
TRUE: Error.
FALSE: No error.
Additional Information
Precautions for Correct Use
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