Mitsubishi Electric QD77MS User Manual page 27

In the buffer memory address, "j" in "34720+20j", etc. indicates a value
corresponding to synchronous encoder axis No. such as the following table.
Synchronous encoder axis No.
1
2
3
4
(Note-1): Calculate as follows for the buffer memory address corresponding to each axis.
(Example) For synchronous encoder axis No. 4
34720+20j ([Pr.320] Synchronous encoder axis type)=34720+20 3=34780
j
0
1
2
3
A - 25