Mitsubishi Electric MELSEC FX3U Programming Manual page 138

FX /FX /FX Series Programmable Controllers
3G 3U 3UC
Programming Manual - Basic & Applied Instruction Edition
• When a file register is monitored from peripheral equipment, the data register area [B] inside the data
memory is read.
When "file register device current value change", "file register device forced reset" or "PLC memory all
clear" is executed from peripheral equipment, the file register area [A] inside the program memory is
changed, and then the data is automatically transferred to the data register area [B].
Accordingly, when file registers are to be overwritten, the program memory should be "built-in memory" or
"memory cassette whose protect switch is set to OFF". (The memory cassette cannot be overwritten from
peripheral equipment if its protect switch is set to ON.)
2. File register ↔ Data register <updating the same number registers by BMOV (FNC 15)
instruction>
When the same file register is specified for both
instruction specifies the same-number register update mode and executes the following operation:
Inside built-in
memory or
memory cassette
Program
memory
Program/
comment
D1000
500 points ×
File register
14 blocks
[A]
maximum
(7000 points
maximum)
Inside built-in
memory or
memory cassette
Program
memory
Program/
comment
D1000
File
500 points ×
14 blocks register
maximum
[A]
(7000 points
maximum)
• When updating the contents of a file register in the same-number update mode, make sure that the file
register numbers at
points specified by "n" does not exceed the file register area. If the number of transfer points exceeds the
file register area, an operation error occurs and the instruction is not executed.
• When
S
file register area and if the number of transfer points is within the file register area also.
136
Inside system
RAM
D 0
Data
memory
Data register
D1100 D1100
Data register
Read
[B]
D1499 D1499
Data register
D7999
Inside system
RAM
D 0
Data
memory
Data
register
D1100 D1100
Data
Write
register
[B]
D1499 D1499
Data register
D7999
and are equal to each other. Also make sure that the number of transfer
S D
and are indexed, the instruction is executed if the actual device number is within the
D
4.9 Data Register and File Register [D]
and in BOMV (FNC 15) instruction, this
S D
Read
OFF
X002
FNC 15
D1100
BMOVP
Same file register number is specified.
•When X002 is set to ON while BMOV instruction direction
reverse flag M8024 is OFF, the contents of a file register
are transferred to the data register area [B] inside the data
memory as shown in the figure on the left.
Write
X001
ON
X003
FNC 15
D1100
BMOVP
Same file register number is specified.
M8001
Always OFF
during operation
•When X003 is set to ON while BMOV instruction direction
reverse flag M8024 is ON, the contents of a data register
inside the data memory are written to the file register area
inside the program memory as shown in the figure on the
left.
4 Devices in Detail
BMOV
direction
M8024
inverse:
OFF
n
S D
D1100 K400
BMOV
direction
M8024
inverse:
ON
n
S D
D1100 K400
BMOV
M8024
direction
inverse:
OFF