Functions And Operation Examples Of Pointers For Interrupt - Mitsubishi Electric MELSEC FX3U Programming Manual

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

4.12.3 Functions and operation examples of pointers for interrupt

There are three types of pointers for interrupt. When in use, they are combined with IRET(FNC03),
EI(FNC04) and DI(FNC05) for interrupt return, enabling interrupt and disabling interrupt.
1. Pointers for input interrupt (delay interrupt): 6 points
The PLC can receive input signals from specific input numbers without influence of the operation cycle of the
PLC. By using these input signals as triggers, the PLC executes interrupt routine programs.
Because pointers for input interrupt can handle signals shorter than the operation cycle, use them for high
priority processing during sequence control and for control handling short pulses.
Input
X000
X001
X002
X003
X004
X005
*1. Cleared when the PLC mode switches from RUN to STOP.
Non-overlap of input numbers
Inputs X000 to X007 are used for high speed counters, input interrupt, pulse catch, SPD/ZRN/DSZR/DVIT
instructions and general-purpose inputs. When assigning functions, there should be no overlap between
those input terminals.
For example, when the input interrupt pointer I001 is used, X000 is occupied. As a result, "C235, C241,
C244, C246, C247, C249, C251, C252 and C254", "input interrupt pointer I000", "pulse catch contact M8170"
and "SPD instruction using X000" cannot be used.
Delay function of input interrupt
This input interrupt has a function to delay the execution of interrupt routine in units of 1ms.
The delay time is specified by the following pattern program.
This delay function can electrically adjust the mounting position of sensors for input interrupts without shifting
the actual position.
I
*2. This function is supported only in FX
154
→ For details on input interrupt function, refer to Section 36.3 and Section 36.4.
Pointer for input interrupt
Interrupt at rising Interrupt at falling
edge edge
I001
I101
I201
I301
I401
I501
Contact for setting delay time
M8393
FNC 12
K
MOV
[1] Delay time (unit: ms)
Program to be processed by input interrupt
→ For details on interrupt function, refer to Chapter 36.
Interrupt disabling flag
I000
M8050
I100
M8051
I200
M8052
I300
M8053
I400
M8054
I500
M8055
•
* D8393
•
FNC 03
IRET
/FX PLCs.
3U 3UC
4.12 Pointer [P and I]
ON duration or OFF duration of
input signal
FX /FX
3U 3UC
*1
*1
*1
5 µs or more
*1
*1
*1
Delay time specifying program
Make sure to describe the delay time specifying
program shown on the left at the head of an
interrupt routine program.
Because this is a pattern program, change only
the delay time [1].
Only a constant (K) or data register (D) can be
used to specify the delay time*.
Interrupt program is finished
4 Devices in Detail
FX
3G
10 µs or more
50 µs or more
10 µs or more
50 µs or more