PROGRAMMING
I
Data
register
D
I
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.
I
Ladderexample
[
DMOV
K8XO
DO
H'-+
'7
The data
XO
to
X1 F
is
stored
into
DO
and
D1
1
Storage
of
data
I
I
Upper
16
bits
'
Lower
16
bits
(X1
F
to
X10)
(XF
to
XO)
Link
register
W
I
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.
62
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