Mitsubishi Melsec-Q Series User Manual page 552

(10) A to Q conversion
ACPU special registers D9000 to D9255 correspond to Q special registers SD1000 to
SD1255 after A to Q/QnA conversion.
(However, the Basic model QCPU and Redundant CPU do not support the A to Q
conversion.)
These special registers are all set by the system, and cannot be set by the user program.
To set data by the user program, correct the program for use of the QCPU special registers.
However, some of SD1200 to SD1255 (corresponding to D9200 to 9255 before conversion)
can be set by the user program if they could be set by the user program before conversion.
For details on the ACPU special registers, refer to the user's manual for the corresponding
CPU, and MELSECNET or MELSECNET/B Data Link System Reference Manuals.
Check "Use special relay/special register from SM/SD1000" for "A-PLC" on the PLC system tab of PLC parameter in GX
Developer when the converted special registers are used with the High Performance model QCPU, Process CPU, and
Universal model QCPU.
When not using the converted special registers, uncheck "Use special relay/special registers from SM/SD1000" to save the
time taken for processing special registers.
Remark
Supplemental explanation on "Special Register for Modification" column
For the device numbers for which a special register for modification is specified, modify it to the special register for
QCPU.
For the device numbers for which
Device numbers for which
12 - 257
is specified, special register after conversion can be used.
is specified do not function for QCPU.