4. Function
36
DIO-48D-LPE
Digital Filter
Using this feature, this product can apply a digital filter to every input pin, thereby preventing the input
signal from being affected by noise or chattering.
Digital Filter Function Principle
The digital filter checks the input signal level during the sampling time of the clock signal. When the
signal level remains the same for the digital filter set time, the digital filter recognizes that signal as the
input signal and changes the signal level of the PC
If the signal level changes at a frequency shorter than the set time, therefore, the level change is ignored.
Input Signal
Filter Setting Time
Invalid
Valid
Input to PC
Input Signal
Digital
Filter
Input to PC
Figure 4.3. Digital Filter Function Principle
Set Digital Filter Time
Set the digital filter time to 0 - 20 (14h).
Setting the digital filter time to 0 disables digital filtering. It is set to 0 when the power is turned on.
Figure 4.4 shows the relationships between digital filter time settings and the actual digital filter times.
Digital Filter Time[sec.] = 2
n
/ (8 x 10
6
)
n: setting data (0 - 20)
Setting
Data(n)
Digital Filter Time
Setting
Data(n)
Digital Filter
Time
Setting
Data(n)
Digital
FilterTime
0 (00h)
The filter function
is not used.
7 (07h)
16
µ
sec
14 (0Eh)
2.048msec
1 (01h)
0.25
µ
sec
8 (08h)
32
µ
sec
15 (0Fh)
4.096msec
2 (02h)
0.5
µ
sec
9 (09h)
64
µ
sec
16 (10h)
8.192msec
3 (03h)
1
µ
sec
10 (0Ah)
128
µ
sec
17 (11h)
16.384msec
4 (04h)
2
µ
sec
11 (0Bh)
256
µ
sec
18 (12h)
32.768msec
5 (05h)
4
µ
sec
12 (0Ch)
512
µ
sec
19 (13h)
65.536msec
6 (06h)
8
µ
sec
13 (0Dh)
1.024msec
20 (14h)
131.072msec
Figure 4.4. Digital Filter Time and Setting Data
CAUTION
-
If you set the digital filter time, the filter applies to all input pins. You cannot apply the filter only to
a specific filter.
-
Do not set Setting Data to a value outside the above range as doing so can cause the board to
malfunction.
Summary of Contents for DIO-48D-LPE
Page 7: ...vi DIO 48D LPE ...
Page 15: ...1 Before Using the Product 8 DIO 48D LPE ...
Page 33: ...2 Setup 26 DIO 48D LPE ...
Page 45: ...4 Function 38 DIO 48D LPE ...