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FX3S/FX3G/FX3GC/FX3U/FX3UC Series
Programming Manual - Basic & Applied Instruction Edition
31 Data Transfer 3 – FNC277 to FNC279
31.1 FNC278 – RBFM / Divided BFM Read
31
FNC277-FNC279
Data
Transfer 3
32
FNC280-FNC289
High-Speed
Processing 2
33
FNC290-FNC299
Extension File
Register Control
34
FNC300-FNC305
FX
3U
-CF-ADP
35
SFC•STL
Programming
36
Interrupt
Function
37
Special Device
38
Error Code
A
Version Up
Information
B
Execution Times
Related devices
→ For the flag use methods for instruction execution complete and instruction execution
abnormally complete, refer to Subsection 6.5.2.
Related instructions
Errors
An operation error is caused in the following case; The error flag M8067 turns ON, and the error code is stored in
D8067.
• When the unit number "m1" does not exist (error code: K6708)
31.1.1 Common items between RBFM (FNC278) instruction and WBFM (FNC279) instruction
Specification of unit number of special function unit/block and buffer memory
→ For the connection method of special function units/blocks, number of connectable units/blocks,
and handling of I/O numbers, refer to the manual of the PLC used and special function unit/block.
1. Unit number "m1" of a special function unit/block
Use the unit number to specify to which equipment the RBFM/WBFM instruction works.
Setting range: K0 to K7
A unit number is automatically assigned to each special function unit/block connected to the PLC.
The unit number is assigned in the way "No. 0 → No. 1 → No. 2 ..." starting from the equipment nearest the main unit.
When the main unit is the FX
3UC-32MT-LT(-2), the unit number is assigned in the way "No. 1 → No. 2 → No. 3 ..."
starting from the equipment nearest to the main unit because the CC-Link/LT master is built into the FX
3UC-32MT-LT
(-2).
2. Buffer memory (BFM) number "m2"
Up to 32767 16-bit RAM memories are built in a special function unit/block, and they are called buffer memories.
The buffer memory number is from "0" to "32766", and the contents are determined according to each special function
unit/block.
Setting range: K0 to K32766
→ For the contents of buffer memories, refer to the manual of the special function unit/block used.
Device Name Description
M8029 Instruction execution complete Turns ON when an instruction is finished normally.
M8328 Instruction non-execution
Turns ON when RBFM (FNC278) or WBFM (FNC279) instruction in
another step is executed for the same unit number.
M8329 Instruction execution abnormally complete Turns ON when an instruction is finished abnormally.
Instruction Description
FROM (FNC 78) Read from a special function block
TO (FNC 79) Write to a special function block
WBFM (FNC279) Divided BFM write
FX3UC-
32MT-LT
(-2)
main unit
Unit No. 0
Built-in
CC-Link/LT
I/O
extension
block
Special
function
block
Special
function
block
Special
function
block
I/O
extension
block
Unit
No. 1
Unit
No. 2
Unit
No. 3