LSIS XBF-AD04A - Page 45

Chapter 2 Analog Input Module (XBF-AD04A)
2 - 11
(2) Filter processing
Filter process function is used to obtain stable digital output value by filtering (delaying) noise or
sudden change of input value. Filter constant can be specified for respective channels through user
program or I/O parameters setting.
• Setting range: 1 ~ 99 (%)
F[n] = (1 - α) x A[n] + α x F [n - 1]
F[n]: Present filter output value
A[n]: Present A/D converted value
F[n-1]: Previous filter output value
Α: Filter constant (0.01 ~ 0.99: previous value added)
 If filter setting value is not specified within 1 ~ 99, RUN LED flickering at an interval of 1 second.
In order to set RUN LED to On status, reset the filter setting value within 1 ~ 99 and then
convert PLC CPU from STOP to RUN. Be sure to use request flag of error clear (UXY.11.0) to
clear the error through modification during RUN.
• Analog input range: DC 0 ~ 10 V, Digital output range: 0 ~ 4000
• If analog input value changes 0 V  10 V (0  4000), filter output value based on  value is
as specified below.
value
Filter output value
 value
1 scan 2 scan 3 scan
*1)
0.01 0 3600 3960 3997 1% inclined toward previous value
*2)
0.66 0 1360 2257 2850 50% inclined toward previous value
*3)
0.99 0 40 80 119 99% inclined toward previous value
*1) 4000 output after about 4 scans
*2) 4000 output after about 18 scans
*3) 4000 output after about 950 scans(1.19 s for 1 channel Run)
 If filter process function is not used, present A/D converted value will be output as it is. The filter
process function takes value-added data between ‘Present A/D converted value’ and ‘Previous
A/D converted value’. And the value-added data can be decided with filter constant. If output
data shakes too much, set a big filter constant value.
(3) Average processing
This process is used to execute A/D conversion of the channel designated for specified frequency or
for specified time and save the average of the accumulated sum on memory. Average processing
option and time/frequency value can be defined through user program or I/O parameters setting for
respective channels.
(a) What is the average process used for
This process is used for A/D conversion of abnormal analog input signal such as noise to a value
near to normal analog input signal.
(b) Average processing type
Average processing type is of time average and count average.
1) Time average processing
▪ Setting range: 4 ~ 16000 (ms)
▪ Average processing count within specified time is decided based on the number of channels
used.
Speed) Conversion( x used) Channels of(Number
timeSetting
count processingAverage 
0 scan