Input Filter Adjustment [D8020] - Mitsubishi Electric MELSEC FX3U Programming Manual

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

37.2.9 Input filter adjustment [D8020]

The inputs X000 to X017
value is set between 0 to 60
D8020 is automatically set to K10 (10 ms).
Input
terminal
X000
*1
X017
*1. X000 to X007 in the FX
*2. 0 to 15 in FX
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.
M8000
RUN monitor
1) FX /FX
3U 3UC
Input number
X000 to X005
X006, X007
X010 to X017
2) FX PLC
3G
Input number
X000, X001, X003, X004
X002, X005, X006, X007
When setting the input filter to "5 µs" or when receiving pulses whose response frequency is 50 k to
*1.
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 kΩ, 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.
*2. X000 to X007 in the FX
• 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 catch (M8170 to M8175) functions.
916
*1
have a digital filter circuit with a setting range of 0 to 60 ms. The digital filter setting
*2
ms (in 1 ms steps) in special data register D8020. After the PLC powers ON,
Filter
0ms
0
1ms
1
Determined by the contents of D8020 (initial value: 10)
10
Input refresh
10ms
Image
60ms
60
memory
, FX -16
3G 3U
PLCs
3G
FNC 12
K 0 D8020
MOV
PLC
Input filter value when "0" is set
*2
Input filter value when "0" is set
-16M , FX
3U
37 Operation of Special Devices (M8000 -, D8000 -)
37.2 Supplement of Special Devices (M8000 - and D8000 -)
and FX -16M .
3UC
*1
5µs
50µs
200µs
10µ
50µs
-16M
3UC