Mitsubishi Electric MELSEC iQ-R Series Programming Manual page 600

Operation error
Error code Description
(SD0)
2840H The device data storage file is not set in parameter.
3405H The value specified by (n) is 0.
3421H When the SP.DEVST instruction is executed, the write count of the day exceeds the value specified in SD771.
When the SP.DEVST instruction is executed, a value out of the range (1 to 32767) is set in SD771.
7 APPLICATION INSTRUCTIONS
598
7.6 Reading/Writing Data Instructions