Mitsubishi Electronics FX3G User Manual

FX

3S

/FX

3G

/FX

3GC

/FX

3U

/FX

3UC

 Series

Programming Manual - Basic & Applied Instruction Edition

36 Interrupt Function and Pulse Catch Function

When any among M8050 to M8055 is set to ON in a program, interrupts from the corresponding input number are
disabled.
(Refer to the previous page table for the correspondence.)

1) Do not use an input two or more times

Make sure that an input relay number used as an interrupt pointer is not used in high-speed counters, pulse catch
functions and applied instructions such as the SPD (FNC 56) speed detection instruction which use the same
input range.

2) Automatic adjustment of the input filter

When an input interrupt pointer I 0  is specified, the input filter of the input relay is automatically changed to the
input filter for high-speed receiving.
Accordingly, it is not necessary to change the filter value using the REFF (FNC 51) instruction or special data
register D8020 (input filter adjustment).
The input filter of an input relay not being used as an input interrupt pointer operates at 10 ms (initial value).

3) Pulse width of input interrupt

For executing input interrupt by an external signal, it is necessary to input the ON or OFF signal having the
duration shown in the table below or more.

*1.

When using the input filter at the filter value of 5 

µs or when receiving a pulse whose response frequency is 

50 k to 100 kHz using a high-speed counter, perform the following:

- Make sure that the wiring length is 5 m or less.
- Connect a bleeder resistor of 1.5 k

Ω (1 W or more) to an input terminal, and make sure that the load 

current of the open collector transistor output in the counterpart equipment is 20 mA or more including the 
input current in the main unit.

4) Using a pointer number two or more times

It is not possible to program an interrupt at the rising edge and an interrupt at the falling edge for an input such as
I001 or I000.

1) When using both an external input interrupt at the rising edge and the output refresh (REF instruction)

In the program example shown below, the output Y000 immediately turns ON when the rising edge of the external
input X000 is detected.

*2.

Make sure to specify a multiple of "8" for the number of inputs/outputs to be refreshed by the REF (FNC 50)
instruction.
If any value other than a multiple of "8" is specified, an operation error occurs and the REF (FNC 50) instruction
is not executed.

FX

3S

X000,X001

10 

µs

X002,X003,X004,X005

50 

µs

FX

3G

, FX

3GC

X000,X001,X003,X004

10 

µs

X002,X005

50 

µs

FX

3U

, FX

3UC

X000 to X005

5 

µs

*1

Step

0

I001

Interrupt

pointer

When the rising edge
of X000 is detected

M8000

RUN
monitor

FNC 06

FEND

FNC 04

EI

Y000

K8

*2

FNC 50

REF

FNC 03

IRET

END

SET

Y000

Interrupts are enabled by the EI instruction.
The main program is described.

The main program is finished by the FEND
instruction.

When an interrupt routine is executed by turning
ON of X000, Y000 is set to ON unconditionally.

The outputs Y000 to Y007 are overwritten with
the latest information by the output refresh
instruction.
If the output refresh instruction is not provided,
Y000 turns ON after the END instruction after the
program execution returned to the main routine.

If "SET Y000" is changed to "RST Y000", Y000 is
immediately set to OFF by turning ON of X000.