Function Of Transfer Between File Registers And Data Registers - Mitsubishi Electric FX3G SERIES Programming Manual

FX /FX /FX Series Programmable Controllers
3G 3U 3UC
Programming Manual - Basic & Applied Instruction Edition
9.6.1

Function of transfer between file registers and data registers

BMOV (FNC 15) instruction has a special function for file registers (D1000 and later).
1. What are file registers
In the parameters, D1000 to D7999 can be set as file registers, and written to and read from the program memory
area.
1) Outline of setting
File registers (D1000 to D7999) do not exist in the initial status. They are valid only when some number of file
registers are secured by parameter setting in a programming tool.
2) Number of file registers
In parameter setting, set 500 file registers as 1 block.
1 to 14 blocks (each of which has 500 file registers) can be set.
1 block occupies 500 steps in the program memory area.
3) Difference between BMOV (FNC 15) instruction and other instructions
The table below shows the difference between BMOV (FNC 15) instruction and other instructions with regard to
file registers (D1000 and later).
Instruction
BMOV instruction
Other applied
instructions
When restoring the power, data registers set as file registers are automatically copied from the file register area
[A] to the data register area [B].
Inside built-in memory
or memory cassette
D1000
500 points ×
14 blocks
maximum
(7000 points
maximum)
2. Cautions on use
1) When updating the contents of a file register with the same number (same-number register update mode), make
sure that the file register number is equivalent between
2) When using file registers in the same-number register update mode, make sure that the number of transfer points
specified by "n" does not exceed the file register area.
3) If the file register area is exceeded while file registers are used in the same-number register update mode, an
operation error (M8067) is caused and the instruction is not executed.
4) In the case of indexing (in the same-number register update mode)
When
S
the file register area and the number of transfer points does not exceed the file register area.
Contents of transfer
Can read from and write to the file register area [A]
inside the program memory.
Can read from and write to the data register area
[B] inside the program memory in the same way as
general data registers.
Program
When power
memory
is turned ON
When PLC
Program/
mode is
comment
changed from
STOP to
File register
RUN
[A]
and are indexing with index, the instruction is executed if the actual device number is within
D
9 Move and Compare – FNC 10 to FNC 19
→ For details on file registers, refer to Section 4.8.
Because the data register area [B] is provided inside the
system RAM in PLCs, its contents can be arbitrarily
changed regardless of the memory cassette format
Inside system
RAM
D 0
Data
memory
Data register
D1000
Write
Data register
[B]
Read
Data register
D7999
The remaining area can be used as general purpose
data registers.
and .
S D
9.6 FNC 15 – BMOV / Block Move
Remarks
−
Devices D1000 and later specified as
operands in applied instructions other
than BMOV (FNC 15) , indirectly
specified values for timers or
counters or devices in RST
instruction are read from and written
to the area [B] in the same way as
general data registers.
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