123
FX
3U
/FX
3UC
Series Programmable Controllers
Programming Manual - Basic & Applied Instruction Edition
4 Devices in Detail
4.11 Pointer [P and I]
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
Operations
2. Pointers for timer interrupt: 3 points
→
For the details of timer interrupt function, refer to Section 35.5.
The PLC executes an interrupt routine program at every specified interrupt cycle time (1 to 99 ms).
Use these pointers for control requiring cyclic processing without regard to the operation cycle of the PLC.
*1.
Cleared when the PLC mode switches from RUN to STOP.
Caution
It is recommended to set the timer interrupt time to 10 ms or more. When the timer interrupt time is set to 9
ms or less, the timer interrupt processing may not be executed at an accurate cycle in the following cases:
• When the processing time of the interrupt program is long
• When an instruction requiring long processing time is used in the main program
Input No.
Interrupt cycle (ms)
Interrupt disabling flag
I6
An integer in the range from 1 to 99 is put in "
" portion of the pointer
name.
Ex: I610 = Timer interrupt at every 10 ms
M8056
*1
I7
M8057
*1
I8
M8058
*1
I001
FNC 04
EI
FNC 06
FEND
FNC 03
IRET
Pointer for
interrupt
Rising edge of X000 is detected
Interrupt enabled
range
Interrupt routine [1]
I101
FNC 03
IRET
Pointer for
interrupt
Rising edge of X001 is detected
Interrupt routine [2]
END
Interrupt is usually disabled in the PLC.
If interrupt is enabled by EI instruction, when
X000 or X001 turns ON while a program is
scanned, the PLC executes the interrupt
routine [1] or [2], and then returns to the main
program by IRET instruction.
•
Make sure to program a pointer for interrupt
(I***) as a label after FEND instruction.
•