HBK DSE, Operating Manual

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DSE
WEB INTERFACE
58
Comb filters
The comb filter eliminates both the selected frequency and its odd multiples (3rd, 5th, 7th,
... multiples of the fundamental) in the measurement signal. This filter type has a faster
transient response than a moving average, and is best suited for interference signals with
low harmonic content.
The cut-off frequency may be between 1 and 100Hz.
7.5.2 Notes on typical applications
Static applications
In static applications, the sample is placed manually on the scale, remains there until the
measurement is taken, and is then removed again. This means you can select a relatively
strong filter in order to obtain a stable measured value display (standstill).
An advantage of static applications is that there is usually no disturbing vibration
generated by the application itself. The only potential source of mechanical vibration
transmitted onto the scale might be from ground vibration, for example, and this would
then need to be taken into account.
Dynamic applications
In dynamic applications, the sample is weighed as it moves across the scale. So the time
window in which the product is registered in its entirety by the scale may be very short.
During this time, the measurement value must have settled with sufficient accuracy, and
there must be enough time to acquire it.
If the filtering is too strong, it will take too long for the full-scale value to be reached,
meaning too few weighing operations are performed or the measurement is taken before
the full-scale value has been reached, and so is incorrect. If the filtering is too weak, the
interference will still be too high, and the scatter of the measurement values will be too
wide, meaning the measurement uncertainty increases.
7.6 Application Mode
In this menu you make the settings for a multi-range weighing machine, and you can
activate the Checkweigher or Filler functions. You will then get another (separate) menu
item for configuration.
Tip
You can take a measurement at any time in the selected application mode, and switch to
the Filter menu item to optimize your signal for analysis.