Fnc278 - Rbfm / Divided Bfm Read - Mitsubishi Electric FX3G SERIES Programming Manual
Programmable controllers
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FX
/FX
/FX
Series Programmable Controllers
3G
3U
3UC
Programming Manual - Basic & Applied Instruction Edition
31.1
FNC278 – RBFM / Divided BFM Read
Outline
This instruction reads data from continuous buffer memories (BFM) in a special function block/unit 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 block/unit for communication by the time division method.
FROM (FNC 78) instruction is also available to read the buffer memory (BFM) data.
1. Instruction format
FNC 278
RBFM
2. Set data
Operand Type
m1
m2
D
n1
n2
3. Applicable devices
Bit Devices
Oper-
and
System User
Type
X Y M T C S D .b KnX KnY KnM KnS
m1
m2
D
n1
n2
: 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
While transfering, "n1" is divided by "n2" so n1/n2 buffer memories (rounded up when there is a remainder) are
transferred per scan time.
Command
input
M8029
M8328
M8329
• 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.
700
Mnemonic
16-bit Instruction
11 steps RBFM
Unit number [0 to 7]
Head buffer memory (BFM) number [0 to 32766]
Head device number storing data to be read from buffer memory (BFM)
Number of all buffer memories (BFM) to be read [1 to 32767]
Number of points transferred in one operation cycle [1 to 32767]
Digit Specification
→ For the unit No., buffer memory (BFM) #, cautions, and program example,
FNC278
m1
m2
RBFM
M
M
M
→ For FROM (FNC 78) instruction, refer to Section 15.9.
Operation Condition
32-bit Instruction
Continuous
Operation
Description
Word Devices
Special
System User
Unit
T
C D R U \G
D
n1
n2
BFM#(m2)
Instruction execution
complete
BFM#(m2+n1-1)
Instruction
non-execution
Instruction execution
abnormally complete
31 Data Transfer 3 – FNC276 to FNC279
31.1 FNC278 – RBFM / Divided BFM Read
Mnemonic
Operation Condition
−
16-bit binary data
Others
Con-
Real
Index
stant
Number
V
Z Modify K
H
E
refer to Subsection 31.1.1.
Unit No. "m1"
*1
Read
*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.)
Data Type
Charac-
Pointer
ter String
" "
P
D
in the PLC.
PLC
D
+n1-1
D
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