Mitsubishi Electric FX3U-CAN, User Manual

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6 Allocation of Buffer Memories
6.2 How to Read/Write from/to Buffer Memory
110
FX
3U
-CAN User's Manual
6.2 How to Read/Write from/to Buffer Memory
To read/write from/to buffer memory in the FX
3U
-CAN, use the FROM/TO instructions or the applied
instructions that directly specify the buffer memory.
FX
3U
/FX
3UC
/FX5U/FX5UC PLC applicable software is required to perform direct specification of the buffer
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.
→
Refer to Programming manual
6.2.1 Direct specification of buffer memory (FX
3U
/FX
3UC
/FX5U/FX5UC only)
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. 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.
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.
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.
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.
Unit No. (0 to 7
*1
) Buffer memory No. (0 to 32766)
U \G
is substituted with a number
READ command
FNC 12
MOV
U1\G30 D10
Transfer result
Unit No.
Buffer memory No.
WRITE command
FNC 12
MOV
H0001 U1\G21
Transfer source
Unit No.
Buffer memory No.
READ command
FNC 78
FROM
K1 K30 D10 K1
Destination register
Number of transfer data points
Unit No.
Buffer memory No.
WRITE command
FNC 79
TO
K1 K21 H0001 K1
Transfer source
Number of transfer data points
Unit No.
Buffer memory No.