FAQ: Difference between revisions

741 bytes added ,  11:33, 27 July 2014
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→‎My extreme values do not appear in the 'monthly' data logs: added 3rd para reflecting answer by Steve in forum
m (Split 'Can I view my Cumulus data on another device? ' out of →‎How do I back up my data (or view it in another Cumulus installation) ?)
m (→‎My extreme values do not appear in the 'monthly' data logs: added 3rd para reflecting answer by Steve in forum)
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== My extreme values do not appear in the 'monthly' data logs  ==
== My extreme values do not appear in the 'monthly' data logs  ==


The data logs are snapshots of the data, taken at the configured interval while Cumulus is running (or at the station's configured interval when data is read from the station's logger). Cumulus reads the station frequently, detecting each change in observations, and can update extremes at each of these reading times.
The data logs are snapshots of the data, taken at the configured interval while Cumulus is running (or at the station's configured interval when data is read from the station's logger directly into the Cumulus monthly log). Cumulus, while it is running, reads the station frequently, detecting each change in observations, and can update extremes at each of these reading times.


If the extreme value reading time did not immediately precede a time at which the data was logged, then it will not appear in the log. This is most noticeable with wind gusts, the value of which can change rapidly between log entries.
If the extreme value reading time did not immediately precede a time at which the data was logged, then it will not appear in the log. This is most noticeable with wind gusts, the value of which can change rapidly between log entries.
Cumulus is designed to be kept running, if you only run it once a day, then the information it reads from the station's logger during catch up may miss extremes. For example when Cumulus reads the archive temperatures from a Davis station,  (in a compromise to allow Cumulus to have as much code as possible that is common to all weather station types) the design means that it ignores the first and second figures representing highest and lowest reported at each logged time, just reading the third figure that, depending on console configuration, is either the average value over the archive period or the final reading of the archive period (I don't know what the default is).


== Cumulus takes a long time to download the data from my Davis station at start up  ==
== Cumulus takes a long time to download the data from my Davis station at start up  ==
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