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FAQ: Difference between revisions
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→What do the various wind speeds in Cumulus correspond to, with Davis stations?
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Davis station firmware supplies two windspeeds, a 3-second average and a 10-minute average (later versions of the firmware also supply a 2-minute average, Cumulus currently doesn't use this). | Davis station firmware supplies two windspeeds, a 3-second average and a 10-minute average (later versions of the firmware also supply a 2-minute average, Cumulus currently doesn't use this). | ||
* The latest Davis 3-second average is treated by Cumulus as 'Latest' (available via <#wlatest>) | * The latest Davis 3-second average is treated by Cumulus as 'Latest' (available via <#wlatest>) | ||
* The highest of the station's 3-second readings over the previous 10 (configurable by adding ''AvgSpeedMinutes=N'' in [[Cumulus.ini#Section:_Station]] where 'N' is number of) minutes becomes the Cumulus 'Gust (available via <#wgust>) | * The highest of the station's 3-second readings over the previous 10 (configurable by adding ''AvgSpeedMinutes=N'' in [[Cumulus.ini#Section:_Station]] where 'N' is number of) minutes becomes the Cumulus 'Gust (available via <#wgust>). Note that the WMO definition of a wind gust is the mean wind speed over a 2 to 3 second sample period (not the maximum instantaneous wind speed). | ||
* The Davis 10-minute average is the Cumulus 'Average' (available via <#wspeed>). | * The Davis 10-minute average is the Cumulus 'Average' (available via <#wspeed>). | ||
Note that if you sample these readings at shorter (real time) intervals it is possible for Cumulus 'Latest' to be lower than Cumulus 'Average' because approximately half of the 3-second wind speeds will be higher and half of them lower than the 10-minute average. | Note that if you sample these readings at shorter (real time) intervals it is possible for Cumulus 'Latest' to be lower than Cumulus 'Average' because approximately half of the 3-second wind speeds will be higher and half of them lower than the 10-minute average. | ||