Reading/Writing Data Instructions - Mitsubishi Electric MELSEC iQ-R Series Programming Manual

7.6

Reading/Writing Data Instructions

Reading/Writing data to data memory
The data write instruction is an instruction to write arbitrary device data to data memory.
Writing the fixed values used for operation and operation results to data memory can prevent data loss when the battery is
low.
The data that has been written to data memory can be read at any time using the data memory read instruction.
■Execution method
Use the SP.DEVST instruction to write device data to data memory.
Use the S(P).DEVLD instruction to read device data from data memory to any specified device.
■Setting method
When the SP.DEVST and S(P).DEVLD instructions are used, a device data storage file must be set up in advance.
[CPU Parameter][File Setting][File Setting for Device Data Storage]
Item
Capacity
File name
If data memory does not have enough free space for creating a device data storage file, an error (error code: 21A1H) occurs.
When the CPU module is switched from STOP to RUN, it is checked to see whether the actual device data storage file
matches the parameter setting. If they do not match, an error (error code: 21A0H) occurs.
Reading/Writing data in the specified file
Use the SP.FREAD instruction to read data from the specified file in the SD memory card. Use the SP.FWRITE instruction to
write data to the specified file in the SD memory card.
When the SP.FREAD or SP.FWRITE instruction is terminated with an error, an error code is stored in the completion status.
The following table lists the error codes stored in the completion status.
Error code Error definition and cause
8000H • SM606 (SD memory card forced disable instruction) is on.
• No SD memory card is inserted.
• The SD memory card is not mounted.
8001H • An access to the SD memory card has failed.
• The SD memory card is full.
• The SD memory card is write-protected.
• The file is set for read only.
• The file size has exceeded its limit.
8002H • The specified file does not exist.
• The disk has become full during writing data to a file.
8003H • The total number of data read from the file has exceeded (d1)+3
(Maximum number of read data).
Description
1K to 512K (words)
DEVSTORE (fixed)
Action
• If SM606 is on, turn it off to cancel the SD memory card forced
disable status.
• Insert an SD memory card.
• Mount the SD memory card.
• Check that the file name character string are correctly specified.
• Delete unnecessary files in the SD memory card to secure free
space.
• Unlock the write protect switch of the memory card.
• Clear the read-only setting.
• Correct the file size so that it is equal to or less than its limit.
• Take measures to reduce noise.
• Reset the CPU module and run it again. If the same error code is
displayed again, the possible cause is a hardware failure of the
SD memory card. Please consult your local Mitsubishi
representative.
• Check that the specified file exists.
• Check that the specified folder path exists.
• Delete unnecessary files in the SD memory card to secure free
space.
• Adjust (d1)+2 (Number of read-target data) or (d1)+3 (Maximum
number of read data).
7 APPLICATION INSTRUCTIONS
7.6 Reading/Writing Data Instructions
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