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MELSEC-F
WHEN COMMUNICATING DATA USING THE MC PROTOCOL9
9 - 11
9.1.4 Character area transmission data
This section explains how to transmit the bit device data and word device data
handled in the character areas, as well as the order of transmission when
communicating data between an external device and the PLC by each command.
The transmission data shown in the examples is contained in character area B when
reading, and in character area C when writing, testing.
(1) Data communication using ASCII code
(a) When reading to or writing from a bit device memory
The bit device memory can be read and written in bit units (one device point)
or word units (16 device points).
How data is transmitted in each case is explained below.
1) Bit units (one point)
In case of bit units, the bit device memory is handled from the designated
head device for the number of designated device points sequentially from
the left. They are expressed as "1" (31
H) if the device is on or "0" (30H) if
the device is off.
(Example)
Indicating the ON/OFF status of five points from M10
2) Word units (16 points)
When the bit device memory is handled as word units, each word is
expressed in hexadecimal values in 4-bit units sequentially from the
higher bit.
(Example)
Indicating the ON/OFF status of 32 points from M16
Indicates that M14 is ON
Indicates that M13 is OFF
Indicates that M12 is ON
Indicates that M11 is OFF
Indicates that M10 is ON
0
30
H
0
30
H
A
41
H
0
30
H
5
35
H
1
31
H
0
30
H
1
31
H
0
30
H
1
31
H
0
30
H
0
30
H
0
30
H
0
30
H
44
H
D
34
H
4
L
L
HH
2
32
H
0
30
H
0
30
H
Head device
Device
point
Data
0
30
H
0
30
H
A
41
H
B
42
H
1
31
H
2
32
H
3
33
H
4
34
H
C
43
H
D
44
H
1
31
H
0
30
H
0
30
H
2
32
H
B15
10101011000100100011
B14B13 B12 B11 B10 B9 B8
B7
B6
B5
B4 B3 B2 B1 B0
010011001101
B15B14 B13 B12B11 B10 B9 B8
B7
B6
B5
B4 B3 B2 B1 B0
AB1234CD
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33 32
30
H
0
30
H
0
32
H
2
44
H
D
34
H
4
LH
0
30
H
0
30
H
0
30
H
Head device
Device
point
Data Data
The device point is "02" in 16-point units.
1: Indicates ON
0: Indicates OFF
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM