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Aanderaa Data Instruments AS – TD302
2.4
Startup delay for calculated wave and tide parameters
The calculations of wave and tide parameters require a number of pressure samples, which will take some time
for the sensor to perform due to the
Number of samples
and the
Tidal Average Period
set by the user. The value
of the output parameter will be 0 until the required samples are available, and the parameter will get a status
code:
Warning Not Ready
.
Once the sensor has performed the required number of samples, wave and tide parameters will be calculated
for every output interval based on the most recent samples in the pressure time series. The pressure time series
are updated according to the sampling rate.
Tide parameters will be calculated after
Tidal Average Period
in seconds.
Wave parameters will be calculated after
rate
Sampling
samples
of
Number
seconds.
The sampling rate is by default 2 Hz, but you can enable high sampling rate of 4 Hz, refer Table 1-3 and Table
1-4.
Note! The pressure time series is cleared: after sensor power up, the Reset and Start command, and a change in
the properties Interval, Enable high sample rate, Tidal Average Period, Enable Tide, Enable Spectrum, Enable
Wave and Number of samples.
Example:
A tide sensor set to a
Tidal Average Period
of ‘40 s’ and a sample rate of 4 Hz will require 40*4 = 160 pressure
points before calculating a tide parameter value. If the
Interval
setting is 2 seconds the sensor will measure 2 * 4
= 8 pressure points before the next calculation.
If the
Interval
setting is 60 seconds all 160 pressure points in the series will be measured, which takes 40 s. The
sensor will enter sleep mode for 20 seconds before it has to start sampling data.