Mitsubishi FX3U-232-BD User Manual page 239

FX Series PLC User's Manual - Data Communication Edition
Computer Link
6. Control Procedures and Setting Methods
6.1 Data Flow by Link
The figures below show images of data flow achieved when data is read from or written to a PLC CPU and
the status is controlled.
In the case of communication in accordance with RS-232C, ignore "485PC-IF" and regard "485ADP" as
"232ADP".
1. When the computer reads data from the PLC
Computer
OS *1
[10] [11]
2. When the computer writes data to the PLC
Computer
OS *1
3. When the PLC sends data to the computer (on-demand function)
Computer
*1
OS
[7]
Write
*1. The OS (standing for "Operating System") indicates the software used to efficiently operate the
resources including the CPUs, memories, terminals, files, and networks using user programs, etc.
485PC-IF
RS-485
RS-232C
[2] Command
[9] Various data
[12] Response
Device
memory
information Interface for
(read)
signal
PLC CPU
conversion
information
(read)
RS-232C
485PC-IF
RS-485
[2] Command,
data, etc. [3]
[8] Response [7]
Device
memory
information
(written)
PLC CPU
information
(written)
485PC-IF
RS-232C
RS-485
[5]
[6] Data
On-demand
data
485ADP
[3] [4]
[8] [7]
[13] [14]
485ADP
[4]
[6]
485ADP
[4] Data
6 Control Procedures and Setting Methods
6.1 Data Flow by Link
PLC CPU
Sequence
OS *1
program
[5] Read
[6] Data
Device
memory, etc.
PLC CPU
Sequence
OS *1
program
[5] Write
Device
memory, etc.
PLC CPU
Sequence
OS *1
program
[2]
[3] Data [1] Sending
Read
request
Device
+
memory, etc.
Data writing
A
B
C
D
E
F
G
H
I
Apx.
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