Introduction to SD card instructions

Using SD card instructions with FP-XH Ethernet type PLCs

Tip

You can use all SD card instructions with an FP-XH Ethernet PLC even though it has no SD card slot. Instead of using an SD card for reading/writing data, the data is stored internally in the RAM.

Please note that data is not stored when the PLC is turned off.
The memory size is limited to 1MB.

FP_SD_GET_FREE_KBYTES returns the amount of free space.

During the execution, the SD memory access active flag (sys_bIsSDMemoryAccessActive) is TRUE, and the SD memory access done flag (sys_bIsSDMemoryAccessDone) is FALSE.
The execution of an SD card instruction is performed through multiple scans.
Upon completion of the execution, the SD memory access error flag (sys_bIsSDMemoryAccessError) turns to TRUE or FALSE, depending on the result. Use this flag to judge whether the SD card instruction has completed normally or abnormally when the SD memory access done flag (sys_bIsSDMemoryAccessDone) turns to TRUE. The error code is stored in a system data register which can be accessed using sys_iSDMemoryAccessErrorCode.
Only one type of SD card instruction can be executed at the same time. To execute more than one instruction, use flags such as the SD memory access active flag (sys_bIsSDMemoryAccessActive).
Use FP_SET_ERROR to clear error flags.
SD card instructions cannot be used in interrupt programs.

(1) The execution of an SD card instruction is performed through multiple scans.
(2) All flags (SD memory access active, SD memory access done, SD memory access error) and registers (error code) are set upon execution of the instruction.
(3) Execution completion is announced at the end of the scan. If an error has occurred, the SD memory access error flag is set to TRUE and the error code is written into a system data register.

NOTE

When one of the following errors is detected, completion is announced immediately and the SD memory access active flag does not turn to TRUE:

Error code	Name of error	Cause	Affected instructions
0	Completed without error
1	No SD card	No SD card is installed, or the cover is open.	All SD card instructions at the time of execution.
2	Write-protection of SD card enabled	The SD card is write-protected.	FP_SD_WRITE* FP_SD_DELETE* FP_SD_MOVE* FP_SD_COPY* FP_SD_RENAME*
3	File/directory name error	The syntax for specifying the file name and directory is wrong or too many subdirectories were specified.	FP_SD__FILE FP_SD__DIR
4	File not specified	The specified file does not exist.	FP_SD__FILE FP_SD__DIR
5	File exists	The specified file already exists.	FP_SD_MOVE* FP_SD_COPY* FP_SD_RENAME*
6	Reading error		All read instructions at the time of execution.
7	Writing error	The specified file is write-protected.	FP_SD_WRITE* FP_SD_DELETE* FP_SD_MOVE* FP_SD_COPY* FP_SD_RENAME*
8	Wrong position	The reading or writing position is wrong.	FP_SD_WRITE FP_SD_READ FP_SD_READ_LINE At the time of execution.
9	SD card full	There is not enough free capacity on the SD card.	FP_SD_WRITE* FP_SD_DELETE* FP_SD_MOVE* FP_SD_COPY* FP_SD_RENAME*
10	Wrong reading format	Error in the conversion format when reading a file.	FP_SD_READ At the time of execution.
11	File access conflict	The specified file is being logged or is being accessed via FTP.	FP_SD_WRITE* FP_SD_DELETE* FP_SD_MOVE* FP_SD_COPY* FP_SD_RENAME*
-1 to -99	Others		All SD card instructions

To save data in a file called abc.txt in the root directory, enter this: \abc.txt
To save data in a file called def.txt in a subdirectory called "sub", enter this: \sub\def.txt
To save data in a file called def.txt in a new subdirectory called "new", enter this: \new\def.txt

NOTE

A subdirectory can only be created directly under its parent directory with one instruction. For directories in lower hierarchy levels, parent directories must be created first.
If two or more files are specified, error 4 "File not specified" occurs.

	SD	SDHC
File system	FAT16	FAT32
Max. length of file name	Supports long file names (VFAT)
Max. capacity	2GB	32GB
Max. file size	2GB	4GB
Max. number of files (8.3 format) in root directory	512	65535
Max. number of files (8.3 format) in sub directory	65534	65534
Max. number of files (long format) in root directory	170	21845
Max. number of files (long format) in sub directory	56634	65534

Item	Description
Long file name	255 bytes (256 bytes including full path)
File name/directory name	ASCII characters (16#20–16#7E)