Index Setting - Mitsubishi MELSEC-Q Series Programming Manual

4.6

Index Setting

(1) Overview of the index setting
(a) The index setting is an indirect setting that uses index registers.
(b) For Universal model QCPU, LCPU, and FXCPU, indexes can be set in 32-bit range in
(2) 16-bit index setting
(a) Setting an index in 16-bit range
X0
X0
(b) Devices that can be used for the index setting (for QCPU (Q mode), LCPU)

4.6 Index Setting

4-40
When the index setting is used in a sequence program, the device consists of 'directly
specified device number' + 'content of index register'.
For example, when D2Z2 is specified and the value of Z2 is 3, D(2+3)=D5 is set as the
target.
addition to 16-bit range.
Values from -32768 to 32767 can be set to index registers.
The following shows how the index is set.
MOV
EN ENO
-1 s d Z0
MOV
EN ENO
D10Z0 s d D0
Index setting
The index setting can be applied to devices used by contacts, coils, basic instructions,
and application instructions except for the restrictions shown in the tables below. The
index setting cannot be applied to labels.
1) Devices that cannot be used for the index setting
Device
E Floating-point data
$ Character string data
Bit specification for word devices
. (D0.1 etc.)
FX, FY, FD Function devices
P Pointers used as labels
I Interrupt pointers used as labels
Z Index registers
S Step relays
TR
SFC transition devices
BL
SFC block devices
*1: SFC transition devices and SFC block devices are devices
for SFC programs. For details, refer to the following manual.
• MELSEC-Q/L/QnA Programming Manual (SFC)
Stores -1 at Z0.
Stores the data of D10Z0=
D{10+(-1)} = D9 to D0.
Description
*1
*1