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8. COMMNICATIONS USING DEDICATED PROTOCOLS
MELSEC-A
8.1 0.4
Writing data to the special function module buffer memory (ACPU common command)
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Special function module buffer
memory write command
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Character area C
b
St. No. :Station number
Designation Method
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Designation in protocol 1 is shown below.
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Number of characters
=
(byte length) x 2 0 1-word
data uses 2 characters. Therefore, a 1-byte data is
\
expressed in
2
digits (hexadecimal)
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POINT
(1) TO designate the byte length, the following condition must be met:
Computer
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. I
5
byte length
5
128
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(2) With some special function modules, 2 or 3 bytes are used to
express the data. Therefore, designate the byte length by referring
to the manuals for each individual module.
;
Designation Example
1
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AJ71 C24
Designation of the special function module
buffer memory address range to be written
To write the data to buffer memory address 27FAH to 27FDH
(4
bytes) of the special-functioA
module (module number 13H) loaded at i/O numbers 120 to 13F in station number
"5".
(Message wait time is
0
msec)
1
NO.
H I L H I L
Indicates that:
Data "01 H " is written to address 27FAH
Data "CDH" is written t o address 27FBH
A
Data "ABH" is written to address 27FCH
Data "EFH" is written to address 27FDH
A
E
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PC
No.
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S f .
N O .
HlL
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PC
NO.
H I L
waittime
I I I 1
Head address
(5 characters
(hexadecimal))
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Byte
length
(2
characters
(hexadecimal))
n
l
L
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S@alfuncGan modul e
number2cherxtem
(hexadecimd)
H
I
L
i
I I I
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Memory
data
to
be
*,itten
8
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-
8
,
8
,
'
H l L l H l L l
lHlL
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Sum
check
code
H I L
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