4.2.3 Calculated quantities
The instrument can calculate several quantities, obtained by relying on one or more primary and constant
quantities and standard quantities collected from an internal library. For example, it’s possible to determine
the dew point temperature by setting temperature and relative humidity of the air as the primary quantities.
It’s also possible to obtain a measure with the moving average of wind’s velocity calculated on a chosen
period.
Measures’ sampling sequence can be configured through 3DOM. Thus, measures are acquired and showed
on the instrument display in the chosen order.
Measures with elaboration element Total are reset on the display at the end of acquisition rate.
4.2.3.1 Position (elevation) of the sun
The calculation of the position (elevation) of the sun is obtained by an adaptation of SolarPosition realized
by Ken Willmott (github.com/KenWillmott/SolarPosition).
You can choose between two different types of
calculated measurement:
➢ Position of the sun (elevation angle measured
over the horizon)
➢ Sun azimuth (azimuth angle measured from
North)
Both calculations require the Alpha-Log setting of the geographical position, provided by the latitude and
longitude values. These values should however be entered during the stage of configuration of the calculated
measure, although they may already have been specified in the registry information (§4.1.1). To trigger the
calculation, it is also necessary to define a measure that has the desired acquisition rate. In the Fig. 23
example the calculation is carried out in correspondence with the acquisition of the measure BATTLevel,
normally activated every minute.
Fig. 23 – Example of calculated measurement configuration of type "Sun position"
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