Input Filter - IDEC FC4A-C10R2 User Manual

5: S F
PECIAL UNCTIONS

Input Filter

The input filter function is used to reject input noises. The catch input function described in the preceding section is used
to read short input pulses to special internal relays. On the contrary, the input filter rejects short input pulses when the
is used with input signals containing noises.
MicroSmart
Different input filter values can be selected for inputs I0 through I7 in four groups using the Function Area Settings.
Selectable input filter values to pass input signals are 0 ms, and 3 through 15 ms in 1-ms increments. Default value is 3 ms
for all inputs I0 through I7. Inputs I10 and above on all-in-one and 20-I/O slim type CPU modules are provided with a
fixed filter of 3 ms. Inputs I10 and above on 40-I/O slim type CPU modules and all expansion input modules have a fixed
filter of 4 ms. The input filter rejects inputs shorter than the selected input filter value minus 2 ms.
Normal inputs require a pulse width of the filter value plus one scan time to receive input signals. When using the input fil-
ter function, select Normal Input on the Special Input page in the Function Area Settings.
Since these settings relate to the user program, the user program must be downloaded to the
any of these settings.
Programming WindLDR
1. From the
WindLDR
appears.
2. Select the Others tab.
Input Filter Group
Group 1 I0
Group 2 I1
Group 3 I2, I3
Group 4 I4 - I7
3. Select an input filter value for each group of inputs.
Input Filter Values and Input Operation
Depending on the selected values, the input filter has three response areas to reject or pass input signals.
Reject area:
Indefinite area:
Pass area:
Example: Input Filter 8 ms
To reject input pulses of 6 ms or less, select input filter
value of 8 ms. Then input pulses of 8 ms plus one scan time
are accepted correctly at the END processing.
5-24
menu bar, select Configure > Function Area Settings. The Function Area Settings dialog box
Input signals do not pass the filter (selected filter value minus 2 ms).
Input signals may be rejected or passed.
Input signals pass the filter (selected filter value).
« FC4A M
Input Rejected
S U ' M
ICRO MART SER S ANUAL
MicroSmart
Input Filter Time Selection
0 ms, 3 through 15 ms
in 1-ms increments
Default: 3 ms
6 ms 8 ms + 1 scan
Indefinite
»
after changing
Accepted