Mitsubishi Electronics MELSEC-F Manuel D’Utilisation
E-17
5 Buffer Memory (BFM)
5.2 Buffer Memory Reading/Writing Method
A
Comm
on I
te
te
ms
B
FX
3U
-4AD
FX
3UC
-4
A
D
C
FX
3U
-4A
D
D
-A
D
P
D
FX
3G
-2A
D
D
-BD
E
FX
3U
-4DA
F
FX
3U
-4D
A
A
-AD
P
P
G
FX
3G
-1D
A
A
-BD
H
FX
3U
-3
A-
ADP
I
FX
3U
-4
A
D
-P
T
-
A
D
P
J
FX
3U
-4A
D
D
-P
TW
-
A
A
D
P
FX
3G
/FX
3U
/FX
3UC
PLC User's Manual - Analog Control Edition
FX
3U
-4DA (4-channel Analog Output)
5.2.1
Buffer memory direct specification (FX
3U
, FX
3UC
PLC only)
When directly specifying the buffer memory, specify the following device in the source or destination area of
the applied instruction as follows:
the applied instruction as follows:
1. Example 1
If the following program is created, data in buffer memory (BFM #10) of unit 1 will be multiplied by the data
(K10), and then the multiplication result will be output to the data registers (D10, D11).
(K10), and then the multiplication result will be output to the data registers (D10, D11).
2. Example 2
If the following program is created, the value in the data register (D20) is added to K10 and written to buffer
memory (BFM #6) of unit 1.
memory (BFM #6) of unit 1.
5.2.2
FROM/TO instruction (FX
3G
, FX
3U
, FX
3UC
PLC)
1. FROM instruction (Reading out BFM data to PLC)
Use FROM instruction to read out the data from the buffer memory.
In a sequence program, use this instruction as follows:
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 of unit No.1
to the data register (D10).
to the data register (D10).
2. TO instruction (Writing PLC data into BFM)
Use the TO instruction to write data to a buffer memory.
In a sequence program, use this instruction as follows:
In a sequence program, use this instruction as follows:
If the above program is created, 1 point of data (H3300) will be written to buffer memory (BFM #0) of unit
No.1.
No.1.
Buffer memory number (0 - 3098)
U \G
Enter a numeric value in
Unit number (0 to 7)
FNC 22
MUL
U1\G10
K10
D10
Multiplier
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
Transfer source
Number of transfer
data points
Unit number
Buffer memory number