109
FX
3U
/FX
3UC
Series Programmable Controllers
Programming Manual - Basic & Applied Instruction Edition
4 Devices in Detail
4.8 Data Register and File Register [D]
1
In
troduct
io
n
2
Ov
e
rv
ie
w
3
In
st
ru
ct
ion
Li
st
4
D
evi
ce
s
in
De
ta
il
5
Speci
fied t
h
e
D
evi
ce &
C
onst
a
nt
6
Bef
o
re
Pr
ogr
a
m
m
ing
7
Bas
ic
In
st
ru
cti
o
n
8
FNC0
0
-FNC0
9
P
ro
g
ra
m F
lo
w
9
FNC1
0
-FNC1
9
M
ov
e
&
C
om
par
e
10
FNC
20-
FNC
2
9
Ar
ith.
&
Logi
c
O
per
at
io
n
2) When file registers of different device numbers are specified for the source and destination
Write
• When X001 is set to ON, the contents of the data
register area [B] are transferred to the data
register area [B] and file register area [A] as
shown in the figure on the left.
If data cannot be written to the file register area
[A] because the protect switch of the memory
cassette (flash memory) is ON, data is written to
only the data register area [B].
4.8.5
Cautions on using file registers
1. Cautions on using a memory cassette
When changing the contents of file registers stored in the flash memory inside the memory cassette, observe
the following condition:
• Set to OFF the protect switch in the memory cassette.
• Allowable writing to a flash memory is up to 10000 times.
When writing data using a continuous operation type instruction in a program, data is written to the flash
memory in every operation cycle of the PLC.
For preventing this, make sure to use a pulse operation type instruction (BMOVP).
• It takes 66 to 132 ms to write data to one serial block (500 points) in the flash memory. Execution of the
program is paused during this period. Because the watchdog timer is not refreshed at this time, it is
necessary to take proper countermeasures such as insertion of WDT instruction in a user program.
2. Cautions on handling file registers in the same-number update mode in BMOV (FNC 15)
instruction
• When updating the contents of the same number file register, make sure that the file register number at
and
are equal to each other.
• Make sure that the number of transfer points specified by "n" does not exceed the file register area.
• If the number of transfer points specified by "n" exceeds the file register area, an operation error (M8067)
occurs and the instruction is not executed.
• In the case of indexing
When
and
are indexed, the instruction is executed if the actual device number is within the
file register area and the number of transfer points is within the file register area also.
Wri
te
Data register
[B]
Inside system
RAM
Inside built-in RAM
memory or
memory cassette
Program
memory
Program/
comment
File register
[A]
D1000
Data
memory
Data register
Data register
D7999
D 0
D1400
D1499
D1499
D1100
Write
500 points
×
14 blocks
maximum
(7000 points
maximum)
D1400
D1199
X001
FNC 15
BMOVP
D1100
D1400
K100
S
D
n
OFF
M8024
S
D
S
D