Mitsubishi Electric FX3U-1PG, User Manual

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7 Buffer Memory
7.1 How to Read/Write from/to Buffer Memory
50
FX
3U
-1PG User's Manual
7. Buffer Memory
The FX
3U
-1PG positioning parameter, control data, and monitor data are read/written from/to the PLC via the
buffer memory (BFM).
When the FX
3U
-1PG power supply is off, the buffer memory data is cleared, and initial values are written
when the power supply is turned on.
The buffer memory is mainly classified into the following three types.
• Positioning parameters (BFM#0 to #15, #32 to #52)
The positioning parameters to set speed and units of measurement.
→
For details, refer to Section 7.3.
• Control data (BFM#16 to #25, #53 to #57)
The control data is user-specified data for controlling the positioning control.
→
For details, refer to Section 7.4.
• Monitor data (BFM#26 to #30, #58 to #62)
Operating conditions for the positioning control are stored as monitor data.
→
For details, refer to Section 7.5.
Caution
The instruction data format (FROM/TO, DFROM/DTO, etc.) must match the target BFM's data format. When
the instruction data format does not match the target BFM's data format (16-bit/32-bit), the FX
3U
-1PG will not
read/write data to the BFM properly, and no error will appear. This may cause an operation error for
positioning.
7.1 How to Read/Write from/to Buffer Memory
To read/write from/to buffer memory in the FX
3U
-1PG, use the FROM/TO instructions or applied instructions
that directly specify the buffer memory. For details on the other methods, refer to the following Manual.
→
Refer to Programming manual.
7.1.1 Direct specification of buffer memory
When directly specifying the buffer memory, specify the following device in the source or destination area of
the applied instruction as follows:
1. Reading out BFM data to PLC (MOV instruction)
If the following program is created, 1 point of data will be read out from the 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 (K4000) will be written to buffer memory BFM#0 of unit No. 1.
Unit No. (0 to 7)
Buffer memory No. (0 to 32766)
is substituted with a number
Read command
Transfer result
Unit No.
Buffer memory No.
U1\G30 D10
FNC 12
MOV
Write command
Transfer source Unit No.
Buffer memory No.
K4000 U1\G0
FNC 12
MOV