781
FX
3U
/FX
3UC
Series Programmable Controllers
Programming Manual - Basic & Applied Instruction Edition
35 Interrupt Function and Pulse Catch Function
35.1 Outline
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35. Interrupt Function and Pulse Catch Function
This chapter explains the built-in interrupt function and pulse catch function in FX PLCs.
35.1
Outline
This section explains the function to immediately execute an interrupt program (interrupt routine) without
affecting the operation cycle of the sequence program (main) while using a interrupt function as a trigger. The
delay by operation cycle and machine operation affected by uneven time intervals in normal sequence
program process can be improved.
1. Input interrupt function (interrupt of external signal input (X))
By the input signal from an input (X000 to X005), the main sequence program is paused, and an interrupt
routine program is executed with priority.
The input interrupt execution timing can be specified on the rising edge or falling edge of the signal by the
pointer number.
→
For the details, refer to Section 35.3.
2. Input interrupt delay function (interrupt of external signal input (X))
By the input signal from an input (X000 to X005), the main sequence program is paused, and an interrupt
routine program is executed with priority after the delay time (set in units of 1 ms).
The input interrupt execution timing can be specified on the rising edge or falling edge of the signal by the
pointer number.
→
For the details, refer to Section 35.4.
3. Timer interrupt function (timer interrupt activated in a constant cycle)
The main sequence program is paused in a constant cycle of 10 to 99 ms, and an interrupt routine program is
executed with priority.
→
For the details, refer to Section 35.5.
4. High speed counter interrupt function (interrupt function given at counting up)
When the current value of a high speed counter reaches a specified value, the main sequence program is
paused and an interrupt routine program is executed with priority.
→
For the details, refer to Section 35.6.
5. Pulse catch function
When the input signal from an input (X000 to X007) turns ON from OFF, a special auxiliary relay M8170 to
M8177 is set in the interrupt processing. By a relay M8170 to M8177 in a normal sequence program, a signal
with ON duration that is too long to be received in the regular input processing can be easily received.
When processing such a signal that turns ON and OFF several times in one operation cycle, however, use
the input interrupt function.
→
For the details, refer to Section 35.7.