Mitsubishi Electronics FX3G User Manual
702
FX
3S
/FX
3G
/FX
3GC
/FX
3U
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3UC
Series
Programming Manual - Basic & Applied Instruction Edition
31 Data Transfer 3 – FNC277 to FNC279
31.1 FNC278 – RBFM / Divided BFM Read
31.1
FNC278 – RBFM / Divided BFM Read
Outline
This instruction reads data from continuous buffer memories (BFM) in a special function unit/block over several
operation cycles by the time division method. This instruction is convenient for reading receive data, etc. stored in
buffer memories in a special function unit/block for communication by the time division method.
FROM (FNC 78) instruction is also available to read the buffer memory (BFM) data.
operation cycles by the time division method. This instruction is convenient for reading receive data, etc. stored in
buffer memories in a special function unit/block for communication by the time division method.
FROM (FNC 78) instruction is also available to read the buffer memory (BFM) data.
→ For FROM (FNC 78) instruction, refer to Section 15.9.
1. Instruction format
2. Set data
3. Applicable devices
S: Except special data register (D)
Explanation of function and operation
1. 16-bit operation (RBFM)
"n1" buffer memory (BFM) units at location # "m2" in special function unit/block No. "m1" are read to
in the PLC.
While transferring, "n1" is divided by "n2" so n1/n2 buffer memories (rounded up when there is a remainder) are
transferred per scan time.
transferred per scan time.
→ For the unit No., buffer memory (BFM) #, cautions, and program example,
refer to Subsection 31.1.1.
• When the instruction is finished normally, the instruction execution complete flag M8029 turns ON. When the
instruction is finished abnormally, the instruction execution abnormally complete flag M8329 turns ON.
• When RBFM (FNC278) or WBFM (FNC279) instruction is executed in another step for the same unit number, the
instruction non-execution flag M8328 is set to ON, and execution of such an instruction is paused.
When execution of the other target instruction is complete, the paused instruction resumes.
When execution of the other target instruction is complete, the paused instruction resumes.
Operand Type
Description
Data Type
m1
Unit number [0 to 7]
16-bit binary
m2
Head buffer memory (BFM) number [0 to 32766]
Head device number storing data to be read from buffer memory (BFM)
n1
Number of all buffer memories (BFM) to be read [1 to 32767]
n2
Number of points transferred in one operation cycle [1 to 32767]
Oper-
and
Type
Bit Devices
Word Devices
Others
System User
Digit Specification
System User
Special
Unit
Index
Con-
stant
stant
Real
Number
Charac-
ter String
Pointer
X Y M T C S D .b KnX KnY KnM KnS T C D R U \G
V Z Modify K H
E
" "
P
m1
m2
m2
S
n1
n2
n2
FNC 278
RBFM
16-bit Instruction
11 steps RBFM
Mnemonic
Operation Condition
Continuous
Operation
−
Mnemonic
Operation Condition
32-bit Instruction
D
D
D
Command
input
M{{
M8029
FNC278
RBFM
m1
m2
D
n1
n2
M8328
M
Instruction execution
complete
complete
Instruction
non-execution
non-execution
Unit No. "m1"
BFM#(m2)
BFM#(m2+n1-1)
PLC
+n1-1
D
D
*1 "n2" buffer memories are read in
each operation cycle. Reading is
executed in "n1/n2" times. ("n1/n2"
is rounded up if it is not an integer.)
executed in "n1/n2" times. ("n1/n2"
is rounded up if it is not an integer.)
Read
*1
M8329
MUU
Instruction execution
abnormally complete
abnormally complete