Common Items Between Rbfm (Fnc278) Instruction And Wbfm (Fnc279) Instruction - Mitsubishi Electric FX3G SERIES Programming Manual

FX /FX /FX Series Programmable Controllers
3G 3U 3UC
Programming Manual - Basic & Applied Instruction Edition
Related devices
Device
M8029 Instruction execution complete
M8328 Instruction non-execution
M8329 Instruction execution abnormally complete
Related instructions
Instruction
FROM(FNC 78)
TO(FNC 79)
WBFM(FNC279)
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 block/unit and buffer memory
1. Unit number "m1" of a special extension unit/block
Use the unit number to specify to which equipment the RBFM/WBFM instruction works.
Setting range: K0 to K7
Unit No. 0
Built-in
CC-Link/LT
FX -
3UC
I/O
32MT-LT
extension
(-2)
block
main unit
A unit number is automatically assigned to each special extension 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
starting from the equipment nearest to the main unit because the CC-Link/LT master is built into the FX
(-2).
2. Buffer memory (BFM) number "m2"
Up to 32767 16-bit RAM memories are built in a special extension 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 block/unit used.
→ For the flag use methods for instruction execution complete and instruction execution
Name
Read from a special function block
Write to a special function block
Divided BFM write
→ For the connection method of special extension units/blocks,
number of connectable units/blocks, and handling of I/O numbers,
refer to the manual of the PLC used and special function block/unit.
Unit Unit
No. 1 No. 2
Special Special
extension extension extension
block block block
-32MT-LT(-2), the unit number is assigned in the way "No. 1 → No. 2 → No. 3 ..."
3UC
31 Data Transfer 3 – FNC276 to FNC279
31.1 FNC278 – RBFM / Divided BFM Read
abnormally complete, refer to Subsection 6.5.2.
Turns ON when an instruction is finished normally.
Turns ON when RBFM (FNC278) or WBFM (FNC279) instruction in
another step is executed for the same unit number.
Turns ON when an instruction is finished abnormally.
Description
Unit
No. 3
I/O Special
extension
block
Description
-32MT-LT
3UC
701
31
32
33
34
35
36
37
38
A
B