5: S
PECIAL
F
UNCTIONS
5-42
FC5A M
ICRO
S
MART
U
SER
’
S
M
ANUAL
FC9Y-B1268
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
MicroSmart is used with input signals containing noises.
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 16- and 24-I/O all-in-one type CPU modules and 32-I/O slim type CPU
modules are provided with a fixed filter of 3 ms. Inputs I30 and above on 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
filter function, select
Normal Input
under Special Inputs on the Input Configuration dialog box in the Function Area Set-
tings.
Since these settings relate to the user program, the user program must be downloaded to the MicroSmart after changing
any of these settings.
Programming WindLDR
1.
From the WindLDR menu bar, select
Configuration
>
Input Configuration
.
The Function Area Settings dialog box for Input Configuration appears.
Input Filter Group
Group 1:
I0
Group 2:
I1
Group 3:
I2, I3
Group 4:
I4 - I7
Input Filter Time Selection
0 ms, 3 through 15 ms
in 1-ms increments
Default: 3 ms
2.
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:
Input signals do not pass the filter (selected filter value minus 2 ms).
Indefinite area:
Input signals may be rejected or passed.
Pass area:
Input signals pass the filter (selected filter value).
Example: Input Filter 8 ms
Indefinite
6 ms
8 ms + 1 scan
Rejected
Accepted
Input
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.
Phone: 800.894.0412 - Fax: 888.723.4773 - Web: www.clrwtr.com - Email: [email protected]
