To my support question to the Davis support I finally received a reply. I asked them why there are differences between console value and WeatherLinkLive value and whether that is an accuracy issue. The first answer was not helpful. So I confronted them with the statement about different calculation. They took a long time to answer.
And from what I understand what they wrote the Davis support does not know for sure. Who then? This was their answer: *Hello, * *That looks like it is the case. They are calculated different. * *To tell you the truth I was not aware of this. * ** * * * *Tom Raymond * *Technical Support Davis Instruments* didier....@gmail.com schrieb am Sonntag, 22. November 2020 um 14:29:48 UTC+1: > thank's Florentin, I've just opened a ticket on Davis support, I will give > you the result next week I hope. > > Le dim. 22 nov. 2020 à 14:24, flor...@pre-vost.fr <flor...@pre-vost.fr> a > écrit : > >> Hi, >> >> I'm the author of WLLDriver on Github. >> Yes, I think that *altimeter *is the good value. But I suggest to >> confirm that by directly ask Davis. >> >> Regards, >> >> Le samedi 21 novembre 2020 à 22:31:04 UTC+1, kk44...@gmail.com a écrit : >> >>> I found that additional information at >>> https://www.manula.com/manuals/pws/davis-kb/1/en/topic/barometric-pressure-issues >>> . >>> >>> There they say, that Davis uses different calculations in different >>> devices: >>> >>> - VP2 and envoy consoles: sea-level pressure ("barometer", QFF) >>> - WeatherLinkLive: altimeter pressure ("altimeter", QNH) >>> - Vue consoles: user can choose between the two >>> >>> So it seems, the author of the "weatherlinkliveudp" driver read the >>> documentation most carefully. >>> >>> And to confuse the user or something, in the LOOP data record, Davis >>> calls the value, what we learnt is altimeter, "bar_sea_level". >>> >>> The archive record contains all the three values barometer, altimeter, >>> and pressure (I checked). Since the "weatherlinkliveudp" driver does not >>> provide a value for barometer, may be, WeeWX calculates it by itself. >>> >>> didier....@gmail.com schrieb am Samstag, 21. November 2020 um 20:54:45 >>> UTC+1: >>> >>>> Thank's a lot >>>> I'm learning a lot of things with you >>>> >>>> Le sam. 21 nov. 2020 à 18:59, vince <vince...@gmail.com> a écrit : >>>> >>>>> On Saturday, November 21, 2020 at 9:31:11 AM UTC-8 kk44...@gmail.com >>>>> wrote: >>>>> >>>>>> didier....@gmail.com schrieb am Samstag, 21. November 2020 um >>>>>> 16:09:22 UTC+1: >>>>>> >>>>>>> Ooops, after 10 mn the 2 values have diverged (only 1 mbar) >>>>>>> The explanation is that weatherlinkliveudp driver uses "altimeter" >>>>>>> and WLLDriver uses "barometer" for the station info >>>>>>> >>>>>> >>>>>> That I do not understand. Does the driver only retrieves the readings >>>>>> from the hardware, doesn't it? So, which way the driver can influence >>>>>> which >>>>>> values is displayed? >>>>>> >>>>>> >>>>> >>>>> There are two pressure-related elements provided by the Davis >>>>> hardware. One is the pressure as reported by the sensor, the other is >>>>> the pressure corrected to sea-level pressure based on your altitude. >>>>> The >>>>> driver code defines which sensor values it uses for what generic weewx >>>>> database element >>>>> >>>>> Both drivers map 'bar_absolute' from the hardware to weewx 'pressure' >>>>> in the database. >>>>> >>>>> But...the two drivers map 'bar_sea_level' from the hardware to >>>>> different elements in weewx's database. >>>>> >>>>> - WLLDriver.py puts the value into 'barometer' in weewx >>>>> - weatherlinkliveudp.py puts the value into 'altimeter' in weewx >>>>> >>>>> According to >>>>> https://github.com/weewx/weewx/wiki/Barometer,-pressure,-and-altimeter, >>>>> the correction math differs slightly, so I'd expect slight differences >>>>> perhaps. A difference of 1 mbar to me isn't something to worry too much. >>>>> >>>>> You're talking 0.1 percent offset. The sensor itself isn't that precise >>>>> to >>>>> begin with. >>>>> >>>>> >>>>> -- >>>>> You received this message because you are subscribed to the Google >>>>> Groups "weewx-user" group. >>>>> To unsubscribe from this group and stop receiving emails from it, send >>>>> an email to weewx-user+...@googlegroups.com. >>>>> >>>> To view this discussion on the web visit >>>>> https://groups.google.com/d/msgid/weewx-user/fccfe641-03d1-473f-910a-c1f0d7aa2cabn%40googlegroups.com >>>>> >>>>> <https://groups.google.com/d/msgid/weewx-user/fccfe641-03d1-473f-910a-c1f0d7aa2cabn%40googlegroups.com?utm_medium=email&utm_source=footer> >>>>> . >>>>> >>>> >>>> >>>> -- >>>> Quel temps fait-il à Auffargis <https://meteo-auffargis.decoodt.eu> ? >>>> >>> -- >> You received this message because you are subscribed to the Google Groups >> "weewx-user" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to weewx-user+...@googlegroups.com. >> > To view this discussion on the web visit >> https://groups.google.com/d/msgid/weewx-user/c278a6af-f77f-4abc-9610-3d34bdc9a5a1n%40googlegroups.com >> >> <https://groups.google.com/d/msgid/weewx-user/c278a6af-f77f-4abc-9610-3d34bdc9a5a1n%40googlegroups.com?utm_medium=email&utm_source=footer> >> . >> > > > -- > Quel temps fait-il à Auffargis <https://meteo-auffargis.decoodt.eu> ? > -- You received this message because you are subscribed to the Google Groups "weewx-user" group. 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