10
DEVICE EXPLANATION
10.6 Index Register(Z) / Standard Device Resister(Z)
10.6.1 Index Register (Z)
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10.6 Index Register(Z) / Standard Device Resister(Z)
10.6.1 Index Register (Z)
(1) Definition
Index registers are used in the sequence program for indirect setting (index
qualification) designations.
An index register point is used for index modification.
The number of index register points is as described below.
Basic model QCPU: Z0 to 9 (10 points)
High Performance model QCPU,
Process CPU, Redundant CPU: Z0 to 15 (16 points)
Universal model QCPU : Z0 to 19 (20 points)
(2) Bit configuration of index register
Note17
(a) Bit configuration and write/read units
The index register, configured in 16 bits per point, writes/reads data in units of 16
bits.
POINT
Index register data are handled as signed data.
F or HEX (hexadecimal), 0000
H
to FFFF
H
can be stored. However, since the most
significant bit is a sign bit, the range of a value that can be specified is -32768 to
32767.
Figure 10.57 Index register
Note17
Figure 10.58 Bit configuration of index register
Universal
UD
Note10.16
X0
K5
Z0
MOVP
SM400
D0Z0 K4Y30
BCD
Index registers consist of 16 bits
per point.
For the Universal model QCPU, the serial access format file register (ZR) can perform 32-bit
indexing with using 2 points of index register.
Universal
UD
Zn
b15
to
b0
The most significant bit is sign bit.
