Pulse Catch Function [M8170 To M8177] - Mitsubishi Electric FX3G SERIES Programming Manual

FX /FX /FX Series Programmable Controllers
3G 3U 3UC
Programming Manual - Basic & Applied Instruction Edition
36.7

Pulse Catch Function [M8170 to M8177]

When the input relay X000 to X007 turns from OFF to ON after the EI (FNC 04) instruction is executed, the special
auxiliary relay M8170 to M8177 is set for interrupt processing.
The EI (FNC 04) instruction is not required in FX
1. Assignment of input numbers and special auxiliary relays
Pulse catch input
X000
X001
X002
X003
X004
X005
X006
X007
*1. Cleared when the PLC mode is changed from STOP to RUN.
*2. This function is supported only in FX
2. Program example
Step
0
M8170
X002
Reset input
EI
X000(Input)
M8170
X002(Reset)
FX /FX PLC
3U 3UC
[X000 to X005]: 5 μs or more
[X006 and X007]: 50 μs or more
When using the pulse catch function at 5 μs or when receiving a pulse whose response frequency is 50 k to
*3.
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 kΩ (1 W or more) to the 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.
3. Cautions on use
1) When receiving an input again, it is necessary to reset the device which was once set using a program.
Accordingly, until a device is reset, a new input cannot be received.
2) When it is necessary to receive continuous short pulses (input signals), use the external input interrupt function or
high-speed counter function.
3) A filter adjustment program is not required.
4) The pulse catch function is executed regardless of the operations of the special auxiliary relays M8050 to M8055
for respectively disabling interrupts.
PLCs.
3G
Pulse catch relay
*1
M8170
*1
M8171
*1
M8172
*1
M8173
*1
M8174
*1
M8175
*1*2
M8176
*1*2
M8177
/FX PLCs.
3U 3UC
FNC 04
The EI (FNC 04) instruction is not required in FX
EI
When the rising edge of X000 is detected,
Y000
M8170 is set as interrupt.
The pulse catch result is reset.
RST M8170
Input pulse width
(shown below)
FX PLC
3G
[X000, X001, X003 and X004]: 10 μs or more
*3
[X002 and X005]: 50 μs or more
36 Interrupt Function and Pulse Catch Function
36.7 Pulse Catch Function [M8170 to M8177]
31
32
33
34
35
PLCs.
3G
36
37
38
A
B
817