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→What do the various wind speeds in Cumulus correspond to, with Fine Offset stations?: slight re-sequencing for better clarity and additon of shorter summary
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== What do the various wind speeds in Cumulus correspond to, with Fine Offset stations? == | == What do the various wind speeds in Cumulus correspond to, with Fine Offset stations? == | ||
Fine Offset sensors measure wind over 48-second intervals, divided into 24 2-second intervals. At the end of each 48-second period, the outdoor unit (anemometer) transmits two values, the "Gust" is calculated from the number of revolutions of the anemometer in two seconds and the "Average" from the number of revolutions in 48 seconds. The console keeps '''overwriting''' the newly received 'Gust' and 'Wind' values to the same area of console memory every 48 seconds, until the station logging interval time is reached, then it moves on to the next memory location, leaving the last values it wrote in the previous console memory location. | Fine Offset sensors measure wind over 48-second intervals, divided into 24 2-second intervals. At the end of each 48-second period, the outdoor unit (anemometer) transmits two values, the "Gust" is calculated from the number of revolutions of the anemometer in last two seconds and the "Average" from the number of revolutions adding all two second counts in the 48 seconds. The console keeps '''overwriting''' the newly received 'Gust' and 'Wind' values to the same area of console memory every 48 seconds, until the station logging interval time is reached, then it moves on to the next memory location, leaving the last values it wrote in the previous console memory location. | ||
Note that Fine Offset Consoles can display a 'MAX' figure, this is highest recorded since it was last reset (on touchscreen models multiple touches of the displayed speed will cause maximum speed, or gust, to be shown, and when a max value is displayed continuing to hold touching that value for 3 seconds will reset max to current value). Cumulus maintains its own various extremes for different periods (e.g high wind and high gust for yesterday on its main screen) calculated from all values processed by Cumulus in that period. | |||
*If Cumulus is not running all the time, on restart it works through the console memory locations and extracts the Fine Offset Wind and Gust in each memory location, i.e. at the station logging interval. | *If Cumulus is not running all the time, on restart it works through the console memory locations and extracts the Fine Offset Wind and Gust in each memory location, i.e. at the station logging interval. | ||
*While Cumulus is running, it reads the current wind speeds (and direction) every 10 seconds. There are new values only every 48 seconds (i.e. every fourth or fifth read). | *While Cumulus is running, it reads the current wind speeds (and direction) every 10 seconds. There are new values only every 48 seconds (i.e. every fourth or fifth read). | ||
Note that the World Meteorological Office definition of a wind gust is the ''mean'' wind speed over a 2 to 3 second sample period (not the ''maximum'' instantaneous wind speed). So the Fine Offset is reporting gust correctly to WMO definition. | |||
Cumulus, for various reasons, uses different terminology, and also has configuration settings which control how some of the wind values are displayed. | Cumulus, for various reasons, uses different terminology, and also has configuration settings which control how some of the wind values are displayed. | ||
* Cumulus 'Average' can be calculated in 3 different ways: | === Summary with default selections === | ||
# '<#wgust>' contains "Calculated Wind Gust (highest value for any 2 seconds in last 10 minutes) Speed" reports highest console gust value in last 10 minutes (this is capturing WMO gust definition over a longer 10 minute reporting interval) | |||
# '<#wlatest>' contains "Latest Peak (the value for last 2 seconds in 48 seconds prior to storing) Wind Speed" taken from console gust value (this is capturing the latest WMO Gust) | |||
# '<#wspeed>' contains "Current Average (over same 48 seconds) Wind Speed" taken from console wind value | |||
=== In detail with all the configurations === | |||
* The highest of the Fine Offset 'Gust' values over the previous 10 (number fixed and not configured to match any other interval set) minutes becomes what Cumulus reports as the 'Gust' speed. | |||
* The value labelled 'Latest' by Cumulus is Fine Offset console 'Gust' value. | |||
* The Cumulus 'Average' can be calculated in 3 different ways: | |||
** The default: If 'Calculate 10-min wind average' is not selected on the Station Settings screen, the console 'Wind' value is reported. | ** The default: If 'Calculate 10-min wind average' is not selected on the Station Settings screen, the console 'Wind' value is reported. | ||
** If 'Calculate 10-min wind average' is selected, but 'Use speed for avg calculation' is | ** If 'Calculate 10-min wind average' is selected, but 'Use speed for avg calculation' is left un-selected; then the average of the Fine Offset 'Gust' values read over the previous N (configurable, defaults to 10) minutes is reported. | ||
** If 'Calculate 10-min wind average' and 'Use speed for avg calculation' are both selected; the average of the Fine Offset 'Wind' values read over the previous N (configurable, defaults to 10) minutes is reported. | ** If 'Calculate 10-min wind average' and 'Use speed for avg calculation' are both selected; the average of the Fine Offset 'Wind' values read over the previous N (configurable, defaults to 10) minutes is reported. | ||
Select value for 'N' using ''AvgSpeedMinutes=N'' in [[Cumulus.ini#Section:_Station]]. | Select value for 'N' using ''AvgSpeedMinutes=N'' in [[Cumulus.ini#Section:_Station]]. | ||
== How do I set up recording wind speeds in Cumulus, with Oregon Scientific and La Crosse stations == | == How do I set up recording wind speeds in Cumulus, with Oregon Scientific and La Crosse stations == | ||