Справочник Пользователя для Mitsubishi Electronics QCPU

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Indexing

(1) Overview of indexing

(a) Indexing is an indirect setting made by using an index register.

When an Indexing is used in a sequence program, the device to be used will become 
the device number specified directly plus the contents of the index register.
For example, if D2Z2 has been specified, the specified device is calculated as 
follows: D(2+3) = D5 and the content of Z2 is 3 become the specified device.

(b) Indexing with 16-bit index registers and indexing with 32-bit index registers are possible 

only for Universal model QCPU.

(2) Indexing with 16-bit index registers

(a) Example of indexing

Each index register can be set between  32768 and 32767.
Indexing is performed in the way shown below:

(b) Devices to which indexing can be used

With the exception of the restrictions noted below, Indexing can be used with devices 
used with contacts, coils, basic instructions, and application instructions.

1) Devices to which indexing can not be used

*1: SFC transfer devices and SFC block devices are devices for SFC use.

Refer to the manual below for how to use these devices.
• QCPU (Q mode)/QnACPU Programming Manual (SFC)

Device

Meaning

K, H

32-bit constant

E

Floating decimal point data

$

Character string data

.

Bit designated for word device

FX, FY, FD

Function devices

P

Pointers used as labels

I

Interrupt pointers used as labels

Z

Index register

S

Step relay

TR

SFC transfer devices*1

BL

SFC block devices*1

X0

MO

V K

Z0

X0

MO

V D10Z0

D0

Indexing

S

tores -1 at Z0.

S

tores the data of D10Z0=

D

{10+(-1)} = D9 at D0.

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