LSI LASTEM M-Log – User’s manual
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5.2.7
Details about calculated measures
If the instrument has been programmed to process one ore more calculated measures, the logical
process will be the following:
1)
Acquisition of all primary measures that allow the estimate of calculated measures; a
calculated measure can be a primary measure for new calculated measure;
2)
Collection of the value of primary measures; if at least one of these values is found to be in
error, its calculated measure will also be indicated in error;
3)
Collection of the value of standard parameters, whenever used in the calculation; the value
of these parameters is decided during the configuration process and cannot therefore be
modified during the survey;
4)
Execution of the estimate;
5)
Allocation of the calculated value to the measure's instant datum.
The acquisition rate of a specific calculated measure is setted by
3DOM
so that it may correspond to
the acquisition rate smaller than the calculated measures it depends on.
5.3
Measure elaboration
For each acquired or calculated measure it is possible to obtain statistical elaborations at a time base
from 1 second to 12 hours. The selected elaboration base is common to all quantities.
Just as with the acquisition process (see §
Errore. L'origine riferimento non è stata trovata.
), the
elaboration process, too, evaluates the time of the built-in clock as a multiple of the elaboration rate
in order to determine the moment in which the elaboration of the statistical data begins. For
example, if the elaboration rate were to be set to 1 hour and 30 minutes, and the current time were
15:24:01, the following elaborations would take place at 16:30:00, 18:00:00, 19:30:00, etc.; the
elaboration uses all instant data acquired or calculated in the chosen elaboration span.
The available statistical elaborations are:
Arithmetical calculations
o
Instantaneous value
o
Mean
o
Minimum
o
Maximum
o
Standard deviation
o
Total
o
% valid data
Vectorial calculations specific for anemometric quantities
o
Prevailing direction
o
Resulting direction
o
Resulting speed
o
Direction standard deviation (sigma-teta)
o
Calm wind percentage
