RSS-2-300W User Manual
20
RSS-2-300W Non-Contact Surface Velocity Radar
4-20 mA max.
– To configure the 4-20 mA output range, the maximum measured value which
will correspond to 20 mA analog output needs to be set. The value is set in the currently
configured measurement unit. Example: if values measured by the instrument are expected to
be within the range of 700 mm/s to 1500 mm/s, it is recommended to configure the maximum
value to slightly above 1500 mm/s (for example 2000 mm/s). Alternatively, if the resolution is
not critical, then minimum value for 4-20 mA output can be left to the instrument maximum of
15000 mm/s
#set_420_max=<value>
#set_thld=<0-100>
Change processing parameters
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.
#set_direction=in
#set_direction=out
#set_direction=both
#set_filter_len=<1-1000>
SNR threshold
- The minimal Signal to Noise Ratio that is required to detect the 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. As a general rule of thumb,
the 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
- 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, larger filter length is recommended.
Direction filter
- Direction filter is used to choose whether the instrument will detect flow
in both directions, or if it should detect only incoming or only outgoing flow. If the direction
filter is set to both directions, the instrument will measure the flow velocity in any direction
and will also report the actual direction of the flow. If the direction filter is set to incoming
direction, then the instrument will reject all radar returns that correspond to outgoing flow,
and vice versa. On monitoring sites where it is expected that the flow will always be in only
one direction, it is recommended to properly configure this parameter to either incoming or
outgoing, as that will improve the consistency of measurements.
#set_thld_snr=<0-5120>
Summary of Contents for RSS-2-300W
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