783
FX
3U
/FX
3UC
Series Programmable Controllers
Programming Manual - Basic & Applied Instruction Edition
35 Interrupt Function and Pulse Catch Function
35.2 Common Items
31
FN
C
275-FN
C
279
Da
ta
Tr
ans
fe
r 3
32
FN
C
280
-F
N
C
28
9
H
igh Speed
Pr
oces
si
ng 2
33
FN
C
290-FN
C
299
Ext
ensi
on Fi
le
R
egi
st
er
34
SF
C
•S
T
L
Pr
o
g
ra
m
m
in
g
35
In
te
rru
p
t
Funct
ion
36
Sp
e
cia
l De
vic
e
37
E
rro
r C
o
d
e
A
V
e
rs
ion U
p
In
fo
rm
a
tio
n
B
Ex
ec
ut
ion Ti
m
e
s
C
Appl
ic
ab
le
In
st
ru
ct
ion Li
st
2. Disabling interrupt pointers (for each interrupt routine) [interrupt function]
1) Programming method
The special auxiliary relays M8050 to M8059 for disabling interrupt are provided.
While an interrupt disable flag (M8050 to M8059) is ON, a corresponding interrupt program is not
executed even if the interrupt disable flag is set to OFF after a corresponding interrupt is generated.
*1.
Cleared when the PLC mode is changed from RUN to STOP.
2) Program example
In the program example shown below, when M8053 is set to ON by M20, the interrupt input I301 triggered
by X003 is disabled.
35.2.2
Related items
1. Using the I/O refresh function (REFF instruction)
When controlling an input relay or output relay in an interrupt program, the I/O refresh instruction REFF (FNC
50) can be used to acquire the latest input information and immediately output the operation result. As a
result, high speed control is achieved without being affected by the operation cycle of the PLC.
2. Interrupt operation while FROM/TO instruction is executed
The interrupt operation is executed as follows depending on the ON/OFF status of the special auxiliary relay
M8028.
1) While M8028 is OFF
While FROM/TO instructions are being executed, interrupts are automatically disabled. Input interrupts
and timer interrupts are not executed.
Interrupts generated during this period are immediately executed when the execution of FROM/TO
instructions are completed.
FROM/TO instruction can be used in an interrupt program when M8028 is OFF.
2) While M8028 is ON
When an interrupt is generated while a FROM/TO instruction is being executed, execution of the FROM/
TO instruction is paused and the interrupt is immediately executed.
FROM/TO instructions cannot be used in an interrupt routine program when M8028 is ON.
Input interrupt
The input interrupts X000 to X005 correspond to M8050 to M8055
*1
respectively. When a relay
M8050 to M8055 turns ON, a corresponding input interrupt is disabled.
Timer interrupt
The timer interrupts I6
to I8
correspond to M8056 to M8058
*1
respectively. When a
relay M8056 to M8058 turns ON, a corresponding timer interrupt is disabled.
High speed counter
interrupt
When M8059
*1
turns ON, all of the high speed counter interrupts I010 to I060 are disabled.
M8053
Interrupt
routine
Interrupts are
enabled
FNC 04
EI
FNC 06
FEND
FNC 03
IRET
I301
Interrupt
pointer
Command to disable
an interrupt triggered
by X003
When the rising edge of X003 is detected
END
M20