Manufacturer Specific Profile Area
CAN-CBX-AI420
Manual • Doc.-No.: C.3030.21 / Rev. 1.4
Page 95 of 103
7.11.7 Average N (2403
h
)
Index
Sub-
index
Description
Value range
Default
Data type
Access
mode
2403
h
0
Number of entries
4
4
unsigned 8
ro
1
Average_Count_1
0...5
5
unsigned 8
rw
2
Average_Count_2
0...5
5
unsigned 8
rw
3
Average_Count_3
0...5
5
unsigned 8
rw
4
Average_Count_4
0...5
5
unsigned 8
rw
This object defines, how many buffered analog values are used to calculate the moving average.
With a read access on the analog values the average of the last 2
(Average_Count_x)
samples is read.
After every conversion a new average is available, because the A/D-values are buffered in a ring
buffer.
The number of the averaged values is calculated as:
number of averaged values = m
m = 2
(Average_Count_x)
It can be averaged from the last 1, 2, 4, 8, 16 or 32 (default) values.
Note:
For input signals with a frequency << F
sample
the filter improves the resolution by
Average_Count /2
bits .
Furthermore a Notchfilter characteristic can be obtained with zero points at
F
sample
/2
k
with k = 1 ... Average_Count_x.
Example:
At a sample-frequency of 200 Hz and Average_Count = 2 a suppression of the frequency of 100 Hz and
50 Hz can be obtained.
Advantage:
After every conversion a new average is available.
Disadvantage: Higher internal calculating effort as for the addition of the measured values
(see object 2402
h
)
