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MELSEC-Q
10 DEVICES
10.2.13 Link registers (W)
(1) Definition
(a) A link register is the High Performance model QCPU memory used to
refresh the High Performance model QCPU with data from the link registers
(LW) of intelligent function modules including MELSECNET/H network
module.
Link registers are used to store numeric data (-32768 to 32767, or 0000
H
to
FFFF
H
).
High Performance model QCPU
Link register
W0
MELSECNET/H network module
Link register
LW0
Link refresh
setting range
Link refresh
When used outside the MELSECNET/H network system's range, link
registers can serve as data registers.
(b) Link registers, which consist of 16 bits per point, read and write data in 16
bit units.
Wn
b15
b0
(c) If the link registers are used for 32-bit instructions, the data is stored in
registers Wn and Wn + 1. The lower 16 bits of data are stored in the link
register No. (Wn) designated in the sequence program, and the higher 16
bits of data are stored in the designated register No. + 1 (Wn + 1).
For example, if link register W12 is designated in the DMOV instruction, the
lower 16 bits are stored in W12, and the upper 16 bits are stored in W13.
K500000 W12
DMOV
W13
Upper 16 bits Lower 16 bits
W12
Processing object: W12, W13
In two link register points, -2147483648 to 2147483647 or 0
H
to
FFFFFFFF
H
data can be stored.
(d) Data stored by the link register is maintained until another data is save.
REMARK
The MELSECNET/H network module has 16384 link register points. The High
Performance model QCPU has 8192 link register points. When subsequent points
after Point 8192 are used for link registers, change a "number of points" setting of
link registers at the "Device" tab screen in the “(PLC) Parameter" dialog box.
