Mitsubishi MELSEC-F FX3U Series User Manual

B-19
5 Buffer Memory (BFM)
5.2 Buffer Memory Reading/Writing Method
A
Common Items
B
FX
3UC
-4AD
C
FX
3U
-4AD-ADP
D
FX
3U
-4DA-ADP
E
FX
3U
-4AD-PT
-ADP
F
FX
3U
-4AD-TC
-ADP
G
PID Instruction (FNC 88)
FX 3U /FX 3UC Series PLC User's Manual - Analog Control Edition
FX3UC-4AD (4-channel Analog Input)
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
3UC Series PLC.
→ For a detailed description of the software compatible with the FX
3UC Series PLC,
refer to Section 1.4.
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:
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).
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.
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:
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:
Unit number (1 - 7) Buffer memory number (0 - 6999)
U  \G 
Enter a numeric value in 
FNC 22
MUL
U1\G10 K10 D10
Multiple
Multiplication result
Unit number
Buffer memory number
READ command
WRITE command
FNC 20
ADD
D20 K10 U1\G6
Addend
Augend
Unit number
Buffer memory number
Addition
result
( )
READ command
FNC 78
FROM
K1 K10 D10 K1
Transfer-to register
Number of transfer
data points
Unit number
Buffer memory number
WRITE command
FNC 79
TO
K1 K0 H3300 K1
Addend
Number of transfer
data points
Unit number
Buffer memory number

Mitsubishi MELSEC-F FX3U Series Specifications

General

Brand	Mitsubishi
Model	MELSEC-F FX3U Series
Category	Controller
Language	English