The right value is "altimeter" See specs https://www.davisinstruments.com/product_documents/weather/spec_sheets/6100_WL-Live_Spec_Sheet.pdf Le mercredi 2 décembre 2020 à 14:24:37 UTC+1, kk44...@gmail.com a écrit :
> 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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