How To Read/Write From/To Buffer Memory; Direct Specification Of Buffer Memory (Fx 3U /Fx 3Uc /Fx5U/Fx5Uc Only); From/To Instructions; Fx -Can User's Manual - Mitsubishi Electric MELSEC-F FX3U-CAN User Manual

FX -CAN User's Manual
3U
6.2

How to Read/Write from/to Buffer Memory

To read/write from/to buffer memory in the FX
instructions that directly specify the buffer memory.
FX /FX /FX5U/FX5UC PLC applicable software is required to perform direct specification of the buffer
3U 3UC
memory and bit specification of word devices.
For further information on applied instructions, bit specification of word devices, direct specification of buffer
memory or special extension unit/block unit number, refer to following manual.
6.2.1 Direct specification of buffer memory (FX
When directly specifying the buffer memory, specify the following device in the source or destination area of
the applied instruction as follows:
*1
Unit No. (0 to 7 )
*1. Unit No. 2 to No. 16 is assigned when the CPU module is an FX5U/FX5UC.
1. Reading out BFM data to PLC (MOV instruction)
If the following program is created, 1 point of data will be read out from buffer memory BFM #30 of unit No.1
to data register D10.
READ command
Buffer memory No.
2. Writing PLC data into BFM (MOV instruction)
If the following program is created, 1 point of data (H0001) will be written to buffer memory BFM #21 of unit
No.1.
WRITE command
Transfer source
6.2.2

FROM/TO instructions

1. FROM instruction (Reading out BFM data to PLC)
Use the FROM instruction to read the data from the buffer memory.
If the following program is created, 1 point of data will be read out from buffer memory BFM #30 of unit No.1
to data register D10.
READ command
Buffer memory No.
2. TO instruction (Writing PLC data into BFM)
Use the TO instruction to write data to buffer memory.
If the following program is created, 1 point of data (H0001) will be written to buffer memory BFM #21 of unit
No.1.
WRITE command
Buffer memory No.
110
U \G
Buffer memory No. (0 to 32766)
FNC 12
U1\G30
MOV
Unit No.
FNC 12
H0001
MOV
FNC 78
K1
FROM
Unit No.
FNC 79
K1
TO
Unit No.
-CAN, use the FROM/TO instructions or the applied
3U
/FX /FX5U/FX5UC only)
3U 3UC
is substituted with a number
D10
U1\G21
K30 D10 K1
K21 H0001 K1
6 Allocation of Buffer Memories
6.2 How to Read/Write from/to Buffer Memory
→ Refer to Programming manual
Transfer result
Buffer memory No.
Unit No.
Number of transfer data points
Destination register
Number of transfer data points
Transfer source