Character Area Data Transmission; Bit Device Memory - Mitsubishi Electric MELSEC FX Series User Manual

FX communication
7.6

Character Area Data Transmission

The data shown in the following examples are samples of the data used in character area B when
reading or character area C when writing data. (see section 7.4.1 and 7.4.2)
7.6.1

Bit Device Memory

Bit device memory is handled in 1 bit units (1 point) or in word unit (16 points).
1 ) Bit units (units of 1 point)
When handling bit device memory in bit units, the specified number of devices, in an
increasing order from the specified head device, are represented sequentially from the left,
as "1"(31H) when ON, and as "0"(30H) when OFF.
Example: When transmitting the on/off status of five points from M10
2 ) Word units (units of 16 points)
When handling bit device memory in word units, each word (16 bits, highest bit being first) is
expressed as 4 hexadecimal digits (each of 4 bits) starting with the higher digit. Each digit
being represented by the appropriate ASCII character.
Example: When transmitting the on/off status of 32 points from M16
A
B15 B14 B13
1 0 1
M M M
31 30 29
Head device
M 0 0 1 0
4DH 30H 30H 31H 30H 30H
No.of
Head device
device
points
M 0 0 16
0 2
4DH 30H 30H 31H 36H 30H
B 1
B12 B11 B10 B9 B8 B7 B6 B5
0 1 0 1 1 0 0 0
M M M M M M M M
28 27 26 25 24 23 22 21
No.of
Data
device
points
1 0 1 0 1
0 5
31H 30H 31H 30H 31H
35H
The number of devices is "02" because word units are used.
Data Data
A B 1 2 3 4 C D
32H 41H 42H 31H 32H 33H 34H 43H
2 3
B4 B3 B2 B1 B0 B15 B14 B13 B12
1 0 0 1 0 0 0 1
M M M M M M M M
20 19 18 17 16 47 46 45
Head device:
Lowest bit of 1st word
Indicating M14 is ON
Indicating M13 is OFF
Indicating M12 is ON
Indicating M11 is OFF
Indicating M10 is ON
44H
4 C
B11 B10 B9 B8 B7 B6 B5 B4
1 0 1 0 0 1 1 0
M M M M M M M M
44 43 42 41 40 39 38 37 36
Computer link 7
D
B3 B2 B1 B0
0 1 1 0 1
M M M M M
35 34 33 32
Lowest bit
of 2nd word
1:Represents ON
0:Represents OFF
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