Vaisala Observation Display - Manual (Page 18)

User's Guide ______________________________________________________________________
Data Collection
Data collection is handled by a separate Windows background service
("Vaisala Observation Display Service"). The service starts automatically
whenever the computer is restarted, even if no one logs into Windows.
If the administrator has configured data collection to start automatically,
the background service opens the AWS connection and starts processing
data. When the Observation Display user interface is started, the
background service passes the AWS data to the user interface.
Observation Time Series
Each data message from the AWS contains one or more observation
variable values (for example, 1-minute average air temperature reading).
Observation Display displays the latest variable values and stores them
into ASCII files for later use.
The observation time is saved together with the value of the observation
variable. The observation time is set by the AWS.
The sequence of observation variable values forms an observation time
series. You can visualize the various time series using either the real-time
graph display or the View - History dialog.
Note that the observation values shown are not necessarily direct sensor
readings. Instead, they have been processed by the weather station.
By default, all variables are stored and displayed using the same
engineering unit that AWS uses. However, it is possible to define unit
conversions on the user interface (such as displaying wind speed in
knots).
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