7 Communication Using MC Protocol
52
FX3U-ENET-ADP User's Manual
7.3 Message Formats and Control Procedures
When communicating using the MC protocol, the user does not need to specify a response for a
command from an external device; the Ethernet adapter generates it and then responds.
2) Control procedure
The following diagrams illustrate the control procedure for communicating with the MC protocol and the
order of data items in the application data field.
The header section shown in the message explanation diagram " * " of this section corresponds to the
portion of the message explanation diagrams indicated in Subsection 7.5.2 and later.
Refer to Subsection 7.3.3 regarding the content of data items in the message format and data
specification method.
a) Communication in ASCII code
- When reading data from the local station PLC at the external device side
- When writing data to the local station PLC from the external device side
External device side PLC side (Command message)
PLC side External device side (Response message)
30
H
30
H
30
H
46
H
46
H
41
H
30
H
30
H
30
H
30
H
30
H
30
H
35
H
42
H
31
H
32
H
(Data name)
(Example)
Header
0
0
FF
-
A
Subheader
PC No.
Monitoring
timer
Character area A
The contents and arrangement of the data items in
the text differs according to the function to use.
See the sections explaining functions found in
Subsection 7.5.2 and after for details.
Text (Command)
(Normal completion)
Text (Response)
Header
Subheader
Complete code
(Abnormal completion)
Text (Response)
Header
Subheader
Complete code
Abnormal code
When complete code
5B
H is returned
30
H
Exists only when the complete code is "5B."
38
H
80
HL
5B
HL
1200
30
H
H
L
H
L
0
00
-
Character area B
38
H
80
HL
00
*
External device side PLC side (Command message)
PLC side External device side (Response message)
Text (Command)
(Data name)
Header
Subheader
PC No.
Monitoring
timer
Character area C
(Normal completion)
Header
Subheader
Complete code
Text (Response)
The contents and arrangement of the data items in
the text differs according to the function to use.
See the sections explaining functions found in
Subsection 7.5.2 and after for details.
(Abnormal completion)
Text (Response)
Header
Subheader
Complete code
Abnormal code
When complete code
5B
H is returned
Exists only when the complete code is "5B."
(Example)
H
H
L
L
--
F
F
A
000
0
2
30
H
30
H
30
H
30
H
32
H
46
H
46
H
41
H
H
L
8
20
0
30
H
30
H
32
H
38
H
32
H
32
H
38
H
30
H
30
H
31
H
35
H
42
H
H
HL
L
8
5
21
2
0
0
B
*
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