Omega Speaker Systems LCIC-WIM-BEN manual Filtering, Filter1 Filter2 Decimator, Filling Definition

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 N1 successive A/D readings are averaged forming the first level average.

Level 2: Each N2 first level averages are re-averaged forming the second level average. Unlike the N1 readings of level 1, the N2 readings of level 2 are not successive: Only each N3-th ‘first level average’ participates in the second level averaging procedure, the other N3-1 ones being ignored.

As you might guess, N1 is Filter1, N2 is Filter2 and N3 is Decimator. 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.

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