36. Interrupt Function And Pulse Catch Function; Outline - Mitsubishi Electric FX3G SERIES Programming Manual

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

36. Interrupt Function and Pulse Catch Function

This chapter explains the built-in interrupt function and pulse catch function in FX PLCs.
36.1

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.
*1. This function is supported only in DC input type.
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.
*2. This function is supported only in DC input type.
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.
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.
*3. This function is supported only in DC input type.
5. Pulse catch function
When the input signal from an input (X000 to X007) turns from OFF to ON, 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 that remains ON
longer than the receivable range with 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.
*4. This function is supported only in DC input type.
6. Pulse width/Pulse period measurement function
When the input signal from an input (X000, X001, X003 or X004) turns from OFF to ON, the value of the 1/6 μs ring
counter at the input signal rising edge is stored in special data registers.
When the input signal turns OFF from ON, the value of the 1/6 μs ring counter at the input signal falling edge is stored
in special data registers. At the same time, the difference in the counter value between the rising edge and the falling
edge is divided by "60", and the pulse width in units of 10 μs is stored in special data registers.
In the pulse period measurement mode, when the input signal turns from OFF to ON, the difference between the
previous rising of the input signal and the current rising of the input signal is divided by "60", and then the pulse period
in units of 10 μs is stored in special data registers.
*4
36 Interrupt Function and Pulse Catch Function
*1
→ For details, refer to Section 36.3.
*2
→ For details, refer to Section 36.4.
→ For details, refer to Section 36.5.
*3
→ For details, refer to Section 36.6.
→ For details, refer to Section 36.7.
→ For details, refer to Section 36.8.
36.1 Outline
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