Vaisala Hydromet Data Collection Platform - Manual (Page 160)

User’s Guide ______________________________________________________________________
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Generic Statistical Calculations
Generic statistical calculations should be used when the functions
provided by the preconfigured average, minimum, maximum, sum, and
deviation statistics are not suitable.
The statistical calculations are based on data tables and queries made
from them.
A data table is made up of a total period and an update interval. Long
duration or short update intervals require a longer table. You must set
the update interval equal to or multiple of the update interval of the
source value, for example, measurement.
The start time and period of a calculated function can be defined by a
statistical query. A query can contain one or more update intervals.
0605-140 Figure 77 Example of Data Table and Queries
Example table configuration:
- Total period: 3600 seconds
- Update interval: 600 seconds
The average value for the first half an hour can be obtained with the
following query (Query 1 in
Figure 77 on page 158 ):
- Function: Average
- Start: 3600 s
- Period: 1800 s