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8. COMMUNICATIONS USING DEDICATED PROTOCOLS
MELSEC-A
lesignation Examples1
Example 1
:
To start transmission of data, stored in buffer memory at addresses 120H and 121H, by
the sequence program. (Station number is "0",
AJ71C24
I 1 0
addresses are C O to DF,
transmission data is designated in word units.)
Computer
pJ71C24 appends PC number "FE" automatically
I
"1" is ?riven if a
transmlsslon error
1
occurs
Data is transmitted
sequentially in units of 4
bits from the higher bit.
- 1
T O P I H O O O m -
TOP
I
H O O O C
/
H
O
~
I
Y
- - 4
MOV
Request to turn OFF error
indicator LED
Sets word unit for data transmission
Converts the start signal to PLS
Sets transmission data
(1) Designates head address of the
transmission data storage area
an
data length
Resets the on-demand error
(Start is disabled if the content at
address IOCH is "1
".)
(2) Starts the on-demand function
Transmission completed flag
Reads the transmission error storage
area to check transmission status
RCUF END
Address 10CH 1 0 : Correct transmission
1 : Data not transmitted
due to an error
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