Mitsubishi Electronics FX3G User Manual
870
FX
3S
/FX
3G
/FX
3GC
/FX
3U
/FX
3UC
Series
Programming Manual - Basic & Applied Instruction Edition
37 Operation of Special Devices (M8000 -, D8000 -)
37.2 Supplement of Special Devices (M8000 - and D8000 -)
37.2.9 Input filter adjustment [D8020]
The inputs X000 to X017
*1
have a digital filter circuit with a setting range of 0 to 60 ms. The digital filter setting value is
set between 0 to 60
*2
ms (in 1 ms steps) in special data register D8020. After the PLC powers ON, D8020 is
automatically set to K10 (10 ms).
*1.
X000 to X007 in the FX
3G
/FX
3GC
PLCs.
*2.
0 to 15 in FX
3S
/FX
3G
/FX
3GC
PLCs
1. Program example for adjusting the input filter
When the program shown below is executed, the filter constant is changed to 0 ms.
Because the C-R filter is provided in the hardware, however, the filter constant is shown in the table below when "0" is
specified.
Because the C-R filter is provided in the hardware, however, the filter constant is shown in the table below when "0" is
specified.
1) FX
3S
PLC
2) FX
3G
/FX
3GC
PLCs
3) FX
3U
/FX
3UC
PLCs
*3.
When setting the input filter to "5
µs" or when receiving pulses whose response frequency is 50 k to 100 kHz
using high-speed counters, perform the following actions:
-
-
Input wiring length should be 5 m (16' 4") or less.
-
Connect a bleeder resistor (1.5 k
Ω, 1/2 W) to the input terminal. The load current of the open collector
transistor output in the device on the other end should be 20 mA or more including the input current of the
PLC.
PLC.
*4.
In the FX
3U
/FX
3UC
PLCs (16-point type), only X000 to X007 support the input filter adjustment function.
• The input filter constant can be changed as many times as need in the user program.
• This input filter adjustment described here is not required when using high-speed counter, input interrupt, or pulse
• This input filter adjustment described here is not required when using high-speed counter, input interrupt, or pulse
catch (M8170 to M8177) functions.
Input number
Input filter value when "0" is set
X000, X001
10
µs
X002 to X007
50
µs
X010 to X017
200
µs
Input number
Input filter value when "0" is set
X000, X001, X003, X004
10
µ
X002, X005, X006, X007
50
µs
Input number
Input filter value when "0" is set
X000 to X005
5
µs
*3
X006, X007
50
µs
X010 to X017
*4
200
µs
X000
Input
terminal
0ms
1ms
10ms
60ms
0
1
10
60
Image
memory
X017
*1
Input refresh
Determined by the contents of D8020 (initial value: 10)
Filter
M8000
RUN monitor
FNC 12
MOV
K0
D8020