Mitsubishi Electric MELSEC iQ-R Series Programming Manual page 858

Precautions
(d)+1 and (d)+2 are used for the system. Do not change the values.
The Z and LZ save types stored in the area specified by (d) and later are also used for the system. Do not change the values.
Changing the values may cause malfunction of the module.
Operation error
Error code Description
(SD0)
3405H The number of saves in (d)+0 is 0.
The value stored in the system-reserved area in the area specified by (d) has been changed.
A value other than 1 to 3 is set to the Z, LZ save type.
7 APPLICATION INSTRUCTIONS
856
7.11 Index Register Instructions