Mitsubishi MELSEC Q Series Reference Manual page 498

(Stored value)
(Device number)
(Stored value)
(Device number)
(Stored value)
A
(Device number)
APPX - 2
[Designation-4]
A designation of target device number for devices of [Designation-1] and
[Designation-2] above and Section 3.3.1 (3) by qualifying devices with device
numbers and index registers.
For example, by designating D0 and Z0, device memory (D4) can be accessed.
4
Z0
4
D0
+
0
(Access destination)
D4
D5
By designating M0 and Z0, device memory (M16 or M16 to 31) can be accessed.
(Access example in word units)
Z0
16
16
+
0
M0 to M15
(Access destination)
M16 to M31
M32 to M47
[Designation-5]
An indirect designation of a word device in which the stored value in the
designated word device in turn gives the address of the device memory to be
accessed.
In the following case, the device memory address to be accessed, 00002764
assigned to the designated word device.
(At device qualification)
When D0 and Z0 are designated
Z0 0004
H
4
D0
+
0
2764
D4
H
D5 0000
H
POINT
When an external device accesses a device memory by indirect designation,
arrange the following with the programmable controller CPU side before accessing.
(1) Confirm that the address of the memory to which the device memory to be
accessed is correctly assigned, using the ADRSET instruction of the
programmable controller CPU.
(2) Store the address confirmed in 1) above in the device memory designated by
the indirect designation.
(Example)
An example of a sequence program that stores the address of D100 to D0
and D1 for when an external device accesses D100.
(The external device can access D100 by designating D0 indirectly.)
Access to D4 is achieved as expressed in
this sequence program
MOVP K4 Z0
MOVP K
Access to M16 to M31 is achieved as
expressed in this sequence program
MOVP K16 Z0
MOVP K
(At device not qualification)
When D0 is designated
2764
D0
H
0000
D1
H
Device
D2
memory
D3
address to
be accessed
ADRSET D100
APPENDICES
D0Z0
K4M0Z0
, is
H
Device memory
address to be
accessed
D0
APPX - 2