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8. COMMUNICATIONS USING DEDICATED PROTOCOLS
MELSEC-A
8.1 2.7
Extension comment memory readlwrite
(1)
Commands and addresses
Reading or writing extension comment data by designating specific
devices or device numbers is not possible.
(a) AnACPU dedicated commands
Always read or write extension comment data beginning with address
I
OH.
Item
Batch read
Batch write
Note : o
........
Executable
x
........
Not executable
(b) Extension comment memory addresses
The extension comment data storage area is managed in relative
addresses with the head address OOH.
For example, the range that can be set to the head address for an
extension comment memory of 3K bytes is OOH to BFFH.
1) The maximum extension comment memory area is 64K bytes.
The address range for the extension comment data is deter-
mined in accordance with the paraemter set capacity.
2) Designation of the extension comment memory address is made
by converting 5-digit hexadecimal into ASCll code (00000 to
OFFFF).
3) A character error "06H" occurs if the extension comment memory
capacity is not equal to or greater than [head address
+
(set
number of bytes
-
I ) ] .
POINT]
1
Processing
Reads from the extension comment
memory,
Writes to the extension comment memory.
Command
Number
of
Point
Processed
per
,,,,,,,ication
128 bytes
128 bytes
sym-
bol
DR
DW
ASCII
Code
44H, 52H
44H, 57H
-
State of PC CPU
During
STOP
o
o
During RUN
SW22
ON
o
o
SW22
OFF
o
x
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