Mitsubishi Electric MELSEC FX3U Programming Manual page 746

FX /FX /FX Series Programmable Controllers
3G 3U 3UC
Programming Manual - Basic & Applied Instruction Edition
Program example
In the example shown below, data is read from and written to the buffer memories (BFM) in the unit No. 2 as
follows:
• When X000 is set to ON, data stored in D100 to D179 (80 points) are written to the buffer memories (BFM)
#1001 to 1080 in the special function block/unit whose unit number is No. 2 by 16 points in each operation
cycle.
• When X001 is set to ON, the buffer memories (BFM) #2001 to 2080 (80 points) in the special function
block/unit whose unit number is No. 2 are written to D200 to D279 by 16 points in each operation cycle.
X000
BFM write
start
M0
BFM write
start
M8029
Instruction execution complete
M8328
Instruction non-execution
M8329
Instruction execution
abnormally complete
X001
BFM read
start
M5
BFM read
start M8029
Instruction execution complete
M8328
Instruction non-execution
M8329
Instruction execution
abnormally complete
744
FNC279
K2 K1001
WBFM
FNC278
K2 K2001
RBFM
SET M0
D100 K80 K16
RST M0
Y000
RST M0
SET M5
D200 K80 K16
RST M5
Y001
RST M5
END
31 Data Transfer 3 – FNC275 to FNC279
31.1 FNC278 – RBFM / Divided BFM Read
The BFM write start flag is set
to ON.
D100 to D179 (80 points) are written to
the buffer memories #1001 to 1080 in
the unit No. 2 (in 5 operation cycles).
The BFM write start flag is set to OFF.
Execution of the WBFM instruction is
waited.
The BFM write start flag is set to OFF.
The BFM read start flag is set to ON.
The buffer memories #2001 to 2080 (80
points) in the unit No. 2 are read to
D200 to D279 (in 5 operation cycles).
The BFM read start flag is set to OFF.
Execution of the RBFM instruction is
waited.
The BFM read start flag is set to OFF.