FIR filter introduces a delay of 3 samples to the step response. So for a SYNC frequency of 50Hz (i.e.
readings every 20 milliseconds) there is a delay of 60 milliseconds between a weight change and the final
weight reading (before averaging is applied).
Digital Averaging:
In addition to the FIR filter the indicator has two levels of digital averaging.
The first is a fixed length sliding window average where the average of the last ’n’ readings is calculated.
As each new reading is taken the oldest reading is discarded and a new average calculated. The length of
the window is set in OPTION:FILTR from 1 reading to 200 readings. Increasing the average will increase
the step response. For example an average of 10 readings with a SYNC frequency of 50Hz gives a step
response = (10 + 3) / 50Hz = 0.26 seconds.
The second average is similar to the first but has a variable length which grows from 1 reading up to a
maximum of 10 readings. If a disturbance on the scale is detected the old readings are discarded and
a new average starts all over again. Each of the 10 readings is calculated over the window length of
the fixed average. In this way very long term averages are calculated without causing any delays. The
amount of fluctuation that causes the average to be restarted can be selected as FINE or COARSE in
OPTION:JITTER. The COARSE setting is more tolerant of weight change than the FINE.
7.2.6 Subtractive and Additive Tare
The indicator can operate subtractive and additive tare:
Subtractive tare: The weight tared is subtracted from the total weight that can be measured. For
example, if the scale capacity is 100kg and the tare is 40kg, then the scale can only measure a maximum
60kg NET.
Additive tare: The weight tared is not subtracted from the total weight that can be measured. For
example, if the scale capacity is 100kg and the tare is 40kg, then the scale can still measure to a maximum
100kg NET. The maximum amount of additive tare is setup in BUILD:AD.TARE.
*
Underload
Zero Tare
Value
MAX
Negative
Weight
Negative
Weight
Positive
Weight
Overload
Load
Display
Load
Points
Subtractive Tare
*
*
*
*
°
°
°
°
°
°
°
°
°
Underload
Underload
Zero
Zero
AT -Limit
AT -Limit
Tare
Value
Tare
Value
MAX
+Tare Value
Load-limit
Load-limit
Positive
Weight
Positive
Weight
Overload
Overload
Load
Load
Display
Display
Load
Points
Load
Points
Additive Tare (AT) - Tare Value below AT-Limit
Additive Tare (AT) - Tare Value over AT-Limit
= Fixed points - not influenced by Tare-Value
= Variable points - set by Tare-Value
Warning!
When using additive tare, ensure that the scale is rated to the additional load.
43 C500-600-2.0.3
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