Data Register D; Link Register W - Mitsubishi MELSEC A1SCPU Handy Manual

PROGRAMMING
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Data register D
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The data register (D) is a memory area in the PLC which stores data. A data
register consists of 16 bits and allows readiwrite instructions requiring 16 bits, when
32 bit data is handled, two registers are used. The data register number specified
by the 32 bit instruction contains the lower 16 bits and the specified data register
number + 1 contains the upper 32 bits.
The data stored by the sequence program in the data register is retained until new
data is written. To clear the data stored, turn OFF the power to the PLC or use the
reset function of the PLC.
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Ladderexample
[
DMOV K8XO D O
H'-+
'7
The data X O to X1 F is stored into DO and
D1
1
Storage of data
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Upper 16 bits
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Lower 16 bits
(X1
F
to X10)
(XF to XO)
Link register W
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Link registers
(w)
are data registers for use with the data link system. In the data
link system, data is written to the link register by the host station and data read from
the corresponding link registers by the other stations. Therefore link registers allow
data to be transferred between the master and local stations on a data link system.
Before using the link registers, the link range must be set in the parameters of the
master station. Link registers not be used for the data link system can be used as
data registers at each station.
Like data registers, link registers consist of 16 bits and allow read/write operations
requiring 16 bits. When 32 bit data is handled, two registers are used. The link
register number specified by the 32 bit instruction contains the lower 16 bits and the
specified link register number + 1 contains the upper 32 bits.
The data stored by the sequence program in the link register is retained until new
data is written. To clear the data stored, turn OFF the power to the PLC or use the
reset function of the PLC.
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