GLX-RSS-2-300 WL User Manual
17
GLX-RSS-2-300 WL Non-Contact Flow Meter
SNR
SNR Threshold
SNR Threshold
Input Value
Filtered Value
Filter length = 50
Filter length = 10
Processing Parameters
Sensitivity Level
Sensitivity level
– Configures the radar sensitivity level. The sensitivity level threshold is used by
the radar to determine whether the reflected signal is too low to detect any flow. If the instrument is
incorrectly reporting flow when there is no water in the channel, it’s necessary to increase the value of
this parameter.
SNR threshold
SNR threshold
– The minimal Signal to Noise Ratio that is required to detect water flow. If the actual
measured SNR is lower than the threshold, the instrument will not report any flow. Setting SNR
threshold to a higher value will result with more robust measurements but may also result with no
measurements when the water is very smooth. Generally, measurements with SNR below 10 dB may
be inaccurate, and measurements with SNR below 6 dB should not be trusted. The SNR threshold
should be set accordingly.
Filter Length
Filter length
– The length of the averaging filter, in number of readings, to smoothen the measured
values. The instrument performs 10 readings per second, so a filter length value of 50 will result in 5
second integration time. When using longer filter lengths, more measured values are used for filtering,
and the resulting data will be smoother. However, when the surface velocity changes, it will take
more time for the new measurement to be reported. Typically, this parameter should be set to a value
between 50 and 200. For highly turbulent water, longer filter length is recommended.