Conversion Factors For Secondary Units; Digital Filtering (Digfil); Sample Rate (Smprat); Adaptive Filter - Rice Lake 480 Legend Series Technical Manual

9.10 Conversion Factors for Secondary Units

The 480 has the capability to mathematically convert a weight into many different types of units and instantly display those
results with a press of the Unit key.
Secondary units can be specified on the FORMAT menu using the SECNDR parameter.
Multipliers are preconfigured within the indicator.
Note
Ensure that the secondary decimal point position is set appropriately for the scale capacity in the secondary units.
If the converted value requires more digits than are available, the indicator will display an overflow message
OVERFL
( ).
For example, if the primary units are short tons, secondary units are pounds, and the secondary decimal point is set
to 8888.88, the indicator will overflow if five tons or more are applied to the scale. With 5 tons applied, and a
conversion factor of 2000, the secondary units display needs five digits to the left of the decimal point to display the
10000 lb secondary units value.

9.11 Digital Filtering (DIGFIL)

Digital filtering is used to create a stable scale reading in challenging environments. The 480 (firmware version 1.03 and later)
allows selection of Adaptive Filtering, See
filtering.
The A/D sample rate must be selected first, See

9.11.1 Sample Rate (SMPRAT)

The number of weight readings the indicator takes per second is A/D sample rate (SMPRAT).
The A/D sample rate can be 5, 10, 20, or 40 Hz or readings per second.
Set the A/D sample rate to the lowest setting required for the application. Lower settings result in better stability. Better stability
ensures that 5 Hz is more stable than 40 Hz.

9.11.2 Adaptive Filter

The Adaptive Filter has two settings, Sensitivity (AFSENS) and Threshold (AFTHRH). It maintains a running average of the
A/D readings when the weight change remains less than the defined Threshold value. The filter automatically applies less value
to each successive A/D reading the longer the weight change is less than the Threshold value. The amount of value given to
the most recent A/D reading is determined by the sensitivity setting.
Adaptive Filter Sensitivity (AFSENS)
Adaptive filter sensitivity (AFSENS) can be set to HEAVY, MEDIUM or LIGHT. A heavy setting will result in an output that is
more stable to weight changes, than that of light. However, small changes in weight data (a few grads) on the scale base will
not be seen as quickly.
If the difference in typical subsequent weight values on the scale will only be a few grads, use a light setting. On a truck scale
where the changes in subsequent weight values will be 100s of grads, a heavy setting will be more appropriate. When the
weight has not exceeded the Threshold (AFTHRH) setting, the effective response is approximately 30 A/D cycles for LIGHT, 90
A/D cycles for MEDIUM and 180 A/D cycles for HEAVY.
Adaptive Filter Threshold (AFTHRH)
The adaptive filtering threshold (AFTHRH) should be set for the amount of observed instability in the system. This parameter
can be set in the range of 0 to 99999 and is entered as a weight value. When a new sampled weight value is acquired, the
adaptive filter compares the new value to the previous (filtered) output value.
If the difference between the new value and the previous output value is greater than the AFTHRH parameter the adaptive filter
is reset to the new weight value.
If the difference between the new value and the previous output value is less than the AFTHRH parameter, the two values are
averaged together using a weighted average. The weighted average is based on the amount of time the system has been
stable, and selected AFSENS sensitivity.
With the adaptive filter threshold set at zero, determine the amount of instability that is present. Enter this amount of weight
instability to set the threshold of the adaptive filter. The adaptive filter is set to OFF the AFTHRH parameter is set to zero.
Section 9.11.2, Rolling Filtering, See
9.11.1. Select the type of digital filter using DIGFIL parameter.
Section
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Section 9.11.3 on page 70 or OFF for no
Appendix
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