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3.3.2.4 Filtering
Board's digital filtering is used to "smooth" the read samplings by
averaging a pre-set number of the internal readings. It's especially essential
on a noisy environment, as this mechanism reduces system's susceptibility
to short interferences. The 'noise' may be either mechanical (e.g., load cell
vibrations), or electrical.
The digital filter averages the raw internal readings of the A/D, whose rate
is 52,734 A/D readings per second. The behavior of the filtering
mechanism is controlled by three parameters:
• Filter1
• Filter2
• Decimator
These three parameters, described below, are adjustable in order to make
them suit best your application.
The filtering mechanism includes two levels:
Level 1 : Each N
successive A/D readings are averaged forming the first
1
level average.
Level 2 : Each N
first level averages are re-averaged forming the second
2
level average. Unlike the N
are not successive: Only each N
second level averaging procedure, the other N
As you might guess, N
The range of Filter1 & Filter2 is selectable from 2 to 256, where 2 is the
lowest filtering and 256 is the highest filtering.
The range of Decimator is from 1 to 1000.
Note: As described in section 4.1, 4.2 & 4.3.2, user's application may
select the filtering level it requests – either only Filter1, or Filter2 (=both
Filter1 & Filter2). However, the weight on board's numeric LED
display is always after Filter2.
3.3.2.5 Filling Definition
The 'Filling Definition' box includes the parameters used upon a filling
operation in board's Fill Mode, as described in section E.4.
readings of level 1, the N
1
-th 'first level average' participates in the
3
is Filter1, N
is Filter2 and N
1
2
28
readings of level 2
2
-1 ones being ignored.
3
is Decimator.
3
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