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3. SPECIFICATIONS
3.4 Buffer Memory
3.4.1
Buffer memory table
Address
Hexadecimal
Decimal
0000
to 007F
0 to 127
H
H
0080
to 00FF
128 to 255 Output data
H
H
0100
to 010F
256 to 271 Not used
H
H
0110
to 011F
272 to 287
H
H
0120
to 012F
288 to 303
H
H
0130
to 01A7
304 to 423
H
H
01A8
to 01A9
424 to 425 Model display
H
H
01AA
to 01AF
426 to 431 Not used
H
H
01B0
432
H
01B1
433
H
01B2
434
H
01B3
435
H
01B4
to 01B7
436 to 439
H
H
01B8
to 01BB
440 to 443 Not used
H
H
01BC
to 01BF
444 to 447
H
H
01C0
to 01C3
448 to 451 Not used
H
H
01C4
to 01C7
452 to 455
H
H
01C8
to 01CB
456 to 459 Not used
H
H
01CC
to 01CF
460 to 463
H
H
01D0
to 01D3
464 to 467 Not used
H
H
01D4
to 03CF
468 to 975 Parameter
H
H
(7) Unit ready: XnF
This signal indicates whether the unit is able to operate.
It turns ON automatically when unit operation is enabled.
Buffer data is used for data communication between DN91 and the PLC CPU.
It is used for reading and writing of DN91 buffer memory data and for the PLC CPU FROM/TO
instructions.
The buffer memory returns to zero (0) when powered OFF or when the PLC CPU reset.
If the parameters are set by the sequence program, however, the "Parameter" area is
initialized with the parameters that are already set.
The buffer memory table is shown in Table 3.4.
Table 3.4 Buffer Memory Table
Item
Input data
Message communication
command
Message communication
result
Message communication
data
Master communication
status
Error information
Bus error counter
Bus-off counter
Configuration status of
each station
Communication status of
each station
Error status of each
station
Down-station detection
disabled setting
Contents
Stores input data from each slave station.
Stores output data for each slave station.
Stores request data for message
communication.
Stores result data from message
communication.
Stores communication data for message
communication.
Setting is "DN91" in ASCII code
Stores the DN91 status
Upper byte: Error code
Lower byte: Stores station number where the
error occurred.
Stores the number of error detections for
communication data.
Stores the number of communication errors.
Indicates whether parameters are set for
each slave station.
Indicates whether each station is conducting
I/O communication
Indicates whether an error has occurred for
each station.
Sets whether a down slave station is
reflected in the slave down signal (Xn4).
Area to set parameters with a sequence
program.
−
3
8
MELSEC-A
Write Enabled/
See
Disabled by CPU
Page
Disabled
3.4.2 (1)
Enabled
3.4.2 (2)
Enabled
3.4.2 (3)
Disabled
3.4.2 (4)
Enabled
3.4.2 (5)
Disabled
Disabled
3.4.2 (6)
Disabled
3.4.2 (7)
Disabled
3.4.2 (8)
Disabled
3.4.2 (9)
Disabled
3.4.2 (10)
Disabled
3.4.2 (11)
Disabled
3.4.2 (12)
Disabled
3.4.2 (13)
Enabled
3.4.2 (14)
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