Digital Filtering; Digflx Parameters; Dfsens And Dfthrh Parameters - Rice Lake IQ plus 355 Installation Manual

7.7

Digital Filtering

The IQ plus 355 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 7-3 shows the digital filter parameters on the CONFIG menu.
Figure 7-3. Digital Filtering Parameters on the Configuration (CONFIG) Menu
7.7.1

DIGFLx Parameters

The first three digital filtering parameters, DIGFL1,
DIGFL2, and DIGFL3, 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 7-4).
The overall filtering effect can be expressed by adding
the values assigned to the two filter stages:
DIGFLT1 + DIGFLT2
For example, if the filters are configured as
DIGFLT1=16, DIGFLT2=8, the overall filtering
effect is 24 (16 + 8 ). With this configuration, each
A/D reading has a 1-in-24 effect on the displayed
weight value. Setting the filters to 1 effectively
disables digital filtering.
42 IQ plus 355 Installation Manual
Figure 7-4. Flow Diagram for IQ plus 355 Digital Filters
7.7.2

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.