Buffer Memory Reading/Writing Method; Buffer Memory Direct Specification; From/To Instruction (Conventional Method - Mitsubishi MELSEC-F FX3U Series User Manual

FX /FX Series PLC User's Manual - Analog Control Edition
3U 3UC
FX -4AD (4-channel Analog Input)
3UC
5.2

Buffer Memory Reading/Writing Method

To read or write the buffer memory of 4AD, use FROM/TO instruction or the buffer memory direct
specification function.
To use the buffer memory direct specification function, however, it is necessary to adopt the software
compatible with the FX
5.2.1

Buffer memory direct specification

When directly specifying the buffer memory, specify the following device in the source or destination area of
the direct application command as follows:
Unit number (1 - 7)
1. Example 1
If the following program is created, the data in buffer memory (BFM #10) of unit 1 will be multiplied by the data
(K10), and then the multiplication result will be read out to the data registers (D10, D11).
READ command
Unit number
Buffer memory number
2. Example 2
If the following program is created, write the data that the data register (D20) is added to the data (K10) in
buffer memory (BFM #6) of unit 1.
WRITE command
Augend
5.2.2

FROM/TO instruction (conventional method)

1. FROM instruction (BFM Reading out data to PLC)
Use FROM instruction to read out the data from the buffer memory.
In a sequence program, use this instruction as follows:
READ command
Unit number
Buffer memory number
If the above program is created, 1 point of data will be read out from the buffer memory (BFM #10) to the data
register (D10).
2. TO instruction (PLC Writing data into BFM)
Use TO instruction to write data in a buffer memory.
In a sequence program, use this instruction as follows:
WRITE command
Unit number
Buffer memory number
Series PLC.
3UC
→ For a detailed description of the software compatible with the FX
U \G
Enter a numeric value in
Buffer memory number (0 - 6999)
FNC 22
U1\G10
MUL
FNC 20
D20
ADD
FNC 78
K1 K10
FROM
FNC 79
K1 K0
TO
K10 D10
Multiplication result
Multiple
K10 U1\G6
(
Addition
result
Addend
D10 K1
Number of transfer
data points
Transfer-to register
H3300 K1
Number of transfer
data points
Addend
5 Buffer Memory (BFM)
5.2 Buffer Memory Reading/Writing Method
Series PLC,
3UC
refer to Section 1.4.
)
Unit number
Buffer memory number
B-19
A
B
C
D
E
F
G