![Hydronix Hydro-Probe XT Скачать руководство пользователя страница 38](http://html.mh-extra.com/html/hydronix/hydro-probe-xt/hydro-probe-xt_user-manual_2192332038.webp)
38 Hydro-Probe XT User Guide HD0538 Rev: 1.6.0
4 Filtering
The default filtering parameters can be found on Page 63 or in Engineering Note EN0071.
The Raw Unscaled reading, which is measured 25 times per second, may contain a high level of
‘noise’ due to irregularities in the signal as the material flows. As a result, this signal requires a
certain amount of filtering to make it usable for moisture control. The default filtering settings are
suitable for most applications, however they can be customised if required to suit the application.
It is not possible to have default filtering settings that are ideally suited to all applications because
each will have different characteristics. The ideal filter is one that provides a smooth output with a
rapid response.
The Raw Moisture % and Raw Unscaled settings should
not
be used for control purposes.
The Raw Unscaled reading is processed by the filters in the following order; first the Slew Rate
Filters limit any step changes in the signal, then the Digital Signal Processing Filters remove any
high frequency noise from the signal and finally the smoothing filter (set using the Filtering Time
function) smoothes the whole frequency range. Each filter is described in detail below.
4.1
Slew Rate Filters
The Slew Rate Filters are useful for clipping large spikes or troughs in the sensor reading
caused by mechanical interference in a process.
These filters set rate limits for large positive and negative changes in the raw signal. It is
possible to set limits for positive and negative changes separately. Options are: None, Light,
Medium and Heavy. The heavier the setting, the more the signal will be ‘dampened’ and the
slower the signal response.
4.2
Digital Signal Processing
The Digital Signal Processing Filters (DSP) remove excessive noise from the signal using an
advanced algorithm. The filter reduces high frequency noise. The advantage of this filter is
that the DSP filter will treat all signals within a meaningful frequency range as valid. The result
is a smooth signal that responds rapidly to changes in moisture.
DSP filters are particularly useful in high noise applications such as a mixing environment.
They are less appropriate for low noise environment.
Options are: None, Very Light, Light, Medium, Heavy, Very Heavy.
4.3
Filtering Time (Smoothing Time)
The Filtering Time smoothes the signal after it has first passed through the Slew Rate filters
and then the DSP filters. This filter smoothes the whole signal and will therefore slow the
signal response. The Filtering Time is defined in seconds
Options are: 0, 1, 2.5, 5, 7.5, 10 and a custom time of up to 100 seconds.
4.4
Averaging parameters
During averaging the sensor uses the Raw Unscaled value. All the filters are unused. These
parameters determine how the data is processed for batch averaging when using the digital
input or remote averaging They are not normally used for continuous processes.
4.4.1
Average/Hold delay
When using the sensor to measure the moisture content of a material as it is discharged
from a bin or silo, there is frequently a short delay between the control signal issued to
begin the batch and the material beginning to flow over the sensor. Moisture readings
Содержание Hydro-Probe XT
Страница 4: ...4 Hydro Probe XT User Guide HD0538 Rev 1 6 0 ...
Страница 6: ...6 Hydro Probe XT User Guide HD0538 Rev 1 6 0 ...
Страница 8: ...8 Hydro Probe XT User Guide HD0538 Rev 1 6 0 ...
Страница 10: ...10 Hydro Probe XT User Guide HD0538 Rev 1 6 0 ...
Страница 14: ...Chapter 1 Introduction 14 Hydro Probe XT User Guide HD0538 Rev 1 6 0 ...
Страница 42: ...Chapter 4 Configuration 42 Hydro Probe XT User Guide HD0538 Rev 1 6 0 ...
Страница 52: ...Chapter 6 Optimising Sensor and Process Performance 52 Hydro Probe XT User Guide HD0538 Rev 1 6 0 ...
Страница 58: ...Chapter 7 Sensor diagnostics 58 Hydro Probe XT User Guide HD0538 Rev 1 6 0 ...
Страница 60: ...Chapter 8 Technical specification 60 Hydro Probe XT User Guide HD0538 Rev 1 6 0 ...
Страница 66: ...Appendix B Document Cross Reference 66 Hydro Probe XT User Guide HD0538 Rev 1 6 0 ...