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8. COMMUNICATIONS USING DEDICATED PROTOCOLS
MELSEC-A
8.10.4
Writing data to the special function module buffer memory (ACPU common command)
Designation in protocol 1 is shown below.
St. No. :Station number
I
I
(1) To designate the byte length, the following condition must be met:
I
Special function module buffer
memory write command
Character area C
4
.
I
1
1 s byte length s 128
I
(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.
Computer
To write the data to buffer memory address 27FAH to 27FDH
(4
bytes) of the special-functio~
module (module number 13H) loaded at I t 0 numbers 120 to 13F in AISCPU.
(Message wait time is 0 msec)
Number of characters
=
(byte length) x 2 1-word
data uses 2 characten. Therefore, a 1-byte data
is expressed in 2 digits (hexadecimal).
A
2
A1 SJ71 C24
Designation of the special function module
buffer memory address range to be written
Indicates that:
Data '01 H" is written to address 27FAH
Data 'CDH" is written to address 27FBH
Data 'ABH" is written to address 27FCH
Data 'EFH" is written to address 27FDH
I
S u m
c h w t
SodB
HIL
I
st.
NO.
HIL
Check sum is calculated within this range
3
2
I
PC
NO,
H l L
Computer
I
I I
I
( I
to
be
I
t
8
-
8
m
n l ~ l n l ~ l l n l ~
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Byte length
(2 chsracten
(hexadasirna,,)
H I L
I
S v a
hrdmrncdlle
ounbs2charsdsrr
(hex&,"@
n
I
L
I
St.
NO,
HIL
A1 SJ71C24
This indicates that special function
module
I10
allocation is 120 to 13F
E
a
I
I
PC
NO.
HIL
O~&,Y~(&,(~*Y~~~~&YL,JE,A,(&,~II&,&~I~,UI
N
O
O
F
F
T
W
O
O
~
~
F
A
~
~
~
~
~
~
~
C
D
~
A
~
~
E
F
A
~
,
I
,
&,I!,II*IU*,~!~IM,~E~(I*,(&~IH,~
A
K
a .
Message
wa"lme
I I I I
Head address
(5
characters
(hexsd~imel))
1 1 1 1
C O O F F
w . Y h
(&A&
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