6 digital filtering, Digfl x, Dfsens and dfthrh parameters – Rice Lake Counterpart Configurable Counting Indicator - User Manual - Version 2.0 User Manual

Page 88

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82

Counterpart User Manual

9.6

Digital Filtering

The

Counterpart

uses averaged digital filtering to reduce the effect of vibration on weight readings. Adjustable

threshold and sensitivity functions allow quick settling by suspending filter averaging, allowing the weight
reading to jump to the new value. Figure 9-2 shows the digital filter parameters on the CONFIG menu.

Figure 9-2. Digital Filtering Parameters on the Configuration (CONFIG) Menu

Figure 9-3. Flow Diagram for

Counterpart Digital Filters

9.6.1

DIGFLx Parameters

The first three digital filtering parameters, DFLTR1, DFLTRL2, and DFLTR3, are configurable filter stages that
control the effect of a single A/D reading on the displayed weight. The value assigned to each parameter sets the
number of readings received from the preceding filter stage before averaging (see Figure 9-3).

The overall filtering effect can be expressed by adding the values assigned to the three filter stages:

DFLTR1 + DFLTR2 + DFLTR3

For example, if the filters are configured as DFLTR1=4, DFLTR2=8, DFLTR3=8, the overall filtering effect is 20
(4 + 8 + 8). With this configuration, each A/D reading has a 1-in-20 effect on the displayed weight value. Setting
the filters to 1 effectively disables digital filtering.

9.6.2

DFSENS and DFTHRH Parameters

The three digital filters can be used by themselves to eliminate vibration effects, but heavy filtering also increases
settling time. The DFSENS (digital filter sensitivity) and DFTHRH (digital filter threshold) parameters can be
used to temporarily override filter averaging and improve settling time:

DFSENS specifies the number of consecutive scale readings that must fall outside the filter threshold
(DFTHRH) before digital filtering is suspended.

DFTHRH sets a threshold value, in display divisions. When a specified number of consecutive scale
readings (DFSENS) fall outside of this threshold, digital filtering is suspended. Set DFTHRH to NONE
to turn off the filter override.

DFLTR1

64

128

4

16

8

32

256

DFSENS

DFTHRH

32OUT

64OUT

2OUT

8OUT

4OUT

16OUT

128OUT

20D

50D

250D

5D

2D

10D

100D

NONE

200D

1

2

DFLTR2

64

128

4

16

8

32

256

1

2

DFLTR3

64

128

4

16

8

32

256

1

2

DIGFL1= n1

DIGFL2= n2

DIGFL3= n3

3rd Stage

Filter A verage

2nd Stage

Filter A verage

1st Stage

Filter A verage

Displayed

Value

n3

2nd Stage

Filter A verages

n2

1st Stage

Filter A verages

n1

A/D Readings

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