FAQ: Difference between revisions

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== Cumulus doesn’t show the same pressure as my Fine Offset console  ==
== Cumulus doesn’t show the same pressure as my Fine Offset console  ==
Cumulus displays pressure corrected to sea level, which the console calls ‘relative pressure’; it displays the letters "rel" when this is being displayed.  The Fine Offset stations only supply absolute/station pressure to Cumulus, so Cumulus applies the adjustment to sea level. Normally when Cumulus starts, it reads the pressure ‘offset’ (the difference between absolute/station and relative/sea level pressure) from the station so it can use it subsequently to calculate the sea level pressure, but it is possible to define the offset in [[Cumulus.ini#Introduced_for_problems_with_Fine_Offset_family.2C_but_may_be_more_widely_applicable:| cumulus.ini]] instead.  
Cumulus displays pressure corrected to sea level. The console calls this ‘relative pressure’; it displays the letters "rel" when this is being displayed.  The Fine Offset stations only supply absolute/station pressure to Cumulus, so Cumulus applies the adjustment to sea level. It does ''not'' use the altitude setting in the cumulus station configuration screen.
 
Normally when Cumulus starts, it reads the pressure ‘offset’ (the difference between absolute/station and relative/sea level pressure) from the stationit uses this subsequently to calculate the sea level pressure (each time when reading the absolute pressure sent from the station), but it is possible to define the offset in [[Cumulus.ini#Introduced_for_problems_with_Fine_Offset_family.2C_but_may_be_more_widely_applicable:| cumulus.ini]] instead.  


First of all, check that you are comparing the Cumulus display with the ‘relative’ pressure on your console, and that you do not have a 'EWpressureoffset=x.y' line in the [Station] section of cumulus.ini.   
First of all, check that you are comparing the Cumulus display with the ‘relative’ pressure on your console, and that you do not have a 'EWpressureoffset=x.y' line in the [Station] section of cumulus.ini.   
Make sure that you have set your console's relative pressure correctly - see your station manual for how to do this, typically tap the reading three times, then click '+' or '-'.  The support forum includes discussion on where to find isobar charts or other sources to determine what the pressure should be.  Obviously after any adjustment you need to stop Cumulus, because it is when you restart it that Cumulus reads the new pressure offset.


Make sure that you have set your console's relative pressure correctly - see your station manual for how to do this, typically tap the reading three times, then click '+' or '-'.  Obviously you need to stop Cumulus, and restart it, for Cumulus to pick up any change you make to the pressure offset between what the console calls absolute and what the console calls relative pressure.
Sometimes the offset that cumulus reads is clearly garbage, so Cumulus uses zero as a best effort. In this situation, Cumulus will display the same value as the 'absolute' pressure on the console (no "rel" is displayed on the console when it is displaying absolute pressure).  To circumvent this, you can edit cumulus.ini, and in the [Station] section add an entry:  
 
Sometimes the offset that is reads is clearly garbage, so Cumulus uses zero as a best effort. In this situation, Cumulus will display the same value as the 'absolute' pressure on the console (no "rel" is displayed on the console when it is displaying absolute pressure).  To circumvent this, you can edit cumulus.ini, and in the [Station] section add an entry:  


  EWpressureoffset=x.y
  EWpressureoffset=x.y


where x.y is your pressure offset. '''Cumulus will then use this instead of reading it from the station'''.
where x.y is your pressure offset. '''Cumulus will then use this instead of reading it from the station'''.
 
'''Note''' that ''you must supply the offset in hPa'' (i.e. the millibar units that the station works with) and that this circumvention generally stops Cumulus from agreeing with the relative pressure displayed on the console.
'''Note''' that ''you must supply the offset in hPa'' (i.e. the millibar units that the station works with) and that this circumvention stops Cumulus from agreeing with the relative pressure displayed on the console.


== My pressure suddenly dropped! Or suddenly increased!  ==
== My pressure suddenly dropped! Or suddenly increased!  ==
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