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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. The console calls this ‘relative pressure’; it displays the letters "rel" when this is being displayed. The Fine Offset stations only | 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 store absolute/station pressure readings in their weather memory locations updated with each transmission and read by Cumulus. Within Cumulus, the software applies the adjustment to sea level before any further processing. It does ''not'' use the altitude setting in the cumulus station configuration screen. | ||
Normally when Cumulus starts, it reads the | Normally when Cumulus starts, it reads in [http://www.jim-easterbrook.me.uk/weather/mm/ the fixed block] in the console a pair of absolute/station pressure and relative/sea level pressure readings and uses the difference between these as the ‘offset’ in millibar for the station; Cumulus uses this offset subsequently to calculate the sea level pressure (each time when reading the absolute pressure in the weather memory locations of the station), but it is possible to define the offset in [[Cumulus.ini#Introduced_for_problems_with_Fine_Offset_family:| 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 '-'. 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. | ||
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). Often, if you restart Cumulus, it will then be able to read the correct value. If the problem happens often, you can circumvent it by editing cumulus.ini (while Cumulus is stopped), and in the [Station] section add an entry: | Sometimes the offset that cumulus reads from the fixed block is clearly garbage, so Cumulus uses zero instead 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). Often, if you restart Cumulus, it will then be able to read the correct value. If the problem happens often, you can circumvent it by editing cumulus.ini (while Cumulus is stopped), 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 | where x.y is your pressure offset. '''Cumulus will then use this instead of reading the fixed block offset 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 generally stops Cumulus from agreeing with the relative pressure displayed on the console. | ||
