Mitsubishi MELSEC Q Series Programming Manual page 138

(7) Precautions when file registers in the flash memory are used
This section explains the precautions for use of the flash memory.
(a) The following flash memory can be used.
(b) File registers in the flash memory can be only read in a sequence program.
3-48
3) When a block number is switched by the RSET instruction, refresh is
performed to the data of the file register (R) in the switched block number.
When a block number is switched by the RSET instruction, refresh is
performed to the data of the file register (R) in the block number at the time of
the END instruction execution. To read/write the refresh data, specify the file
register of the block number at the time of the END instruction execution.
•Flash card
(Write to the flash memory cannot be performed in a sequence program.)
Sequence program
BMOV D100 R0
BMOV R100 D0
When using the flash memory for the file registers, write data in advance.
Using GX Developer or GX Works2, write data to the flash card.
K10
Write
K10
Read
Flash memory
File register