Andrew, I know Wikipedia has its issues but when you consider the pressures posted here and this <https://en.wikipedia.org/wiki/Atmospheric_pressure#Records> I think it is pretty clear there is an issue with the OPs pressures.
Gary On Monday, 17 February 2020 13:41:43 UTC+10, Andrew Milner wrote: > > pressure, barometer and altimeter look reasonable to me. why are they > wrong? > > > > > On Monday, 17 February 2020 03:09:28 UTC+2, Dan Blanchard wrote: >> >> Andrew, I've set barometer = hardware and altimeter = software and >> pressure = software. I've restarted weewx, but nothing has changed in the >> Loop. >> >> On Friday, February 14, 2020 at 9:30:06 PM UTC-8, Andrew Milner wrote: >>> >>> if indeed, and i now tend to agree, the station displays and outputs a >>> manually adjusted barometer which is set to a sea level reading from local >>> weather stations and not pressure then barometer should be set to hardware >>> and pressure and altimeter set to software, and not as i previously >>> suggested. >>> >>> On Saturday, 15 February 2020 06:22:07 UTC+2, ln77 wrote: >>>> >>>> OK… The “pressure” that your station is displaying is what it should be >>>> displaying: the ambient air pressure, correct for your altitude. In >>>> weewx, >>>> this is called “barometer” because that is what weather stations report >>>> for >>>> barometric pressure. “Altimeter” is basically the same thing; there are >>>> differences in exactly how it is corrected, but those differences are >>>> minor >>>> and can be ignored for now. The distinction between what weewx calls >>>> “barometer” and “pressure” is important, though, for anyone more than a >>>> few >>>> hundred feet above sea level. >>>> >>>> From the manual, it appears that the WS-2813 uses a simple method for >>>> correcting to sea level, by allowing the user to adjust a correction >>>> factor >>>> that is applied to the actual measured pressure until the reading matches >>>> some local reference barometric pressure report. This automatically also >>>> corrects for any errors in the pressure sensor itself, a handy bonus. >>>> There’s not reference in the manual to any other kind of pressure being >>>> reported, so it only makes sense that what it transmits via the USB >>>> interface is also this corrected pressure, i.e., “barometer.” But the >>>> WS28XX driver documentation, and as far as I can tell the code also, >>>> assume >>>> that the pressure reading fro the hardware is what weewx calls “pressure,” >>>> that is, the actual ambient pressure before correction for altitude. As >>>> far as I can tell, all of the WS28XX LaCrosse stations work the same way >>>> as >>>> yours and actually send the corrected barometer reading. Maybe because the >>>> LaCrosse documentation calls it “pressure,” it was mistakenly interpreted >>>> as raw pressure reading in the driver. >>>> >>>> The bottom line is, I’m pretty sure the issue is that the driver is >>>> wrong. I’m not familiar enough with that part of the weewx code to offer >>>> a >>>> fix, but it should be pretty simple for someone who is familiar with that >>>> code. >>>> >>>> -Les >>>> >>>> >>>> >>>> On 14 Feb 2020, at 19:44, Dan Blanchard <[email protected]> wrote: >>>> >>>> It is likely that I am mis-using the terms altimeter, barometer, and >>>> pressure. I'll clarify what I mean here. >>>> >>>> What I previously defined as 'correct' pressure is that the pressure >>>> reported by my station (LaCrosse WS-2813U-IT) matches the National Weather >>>> Service barometer reading ( >>>> https://forecast.weather.gov/MapClick.php?lat=47.715130000000045&lon=-116.94667999999996#.XkdkXDFKiUk). >>>> >>>> For example, *right now* my station is reading 30.06 pressure and the >>>> NWS site is reporting 30.0 barometer. Ultimately I just want my WS-2813 >>>> pressure reading to match the WU pressure reading ( >>>> https://www.wunderground.com/dashboard/pws/KIDPOSTF43). Right now it >>>> appears that WU is reading the weewx barometer reading. Is there a way to >>>> have weewx report the pressure reading to WU? >>>> >>>> My WS-2813 outputs the manually adjusted pressure in the Loop records >>>> (see attachment). I don't see a way to change that. Here is a link to >>>> the >>>> manual ( >>>> https://www.lacrossetechnology.com/media/catalog/product/w/s/ws-2813u-it.pdf >>>> ). >>>> >>>> On Friday, February 14, 2020 at 9:22:17 AM UTC-8, Andrew Milner wrote: >>>>> >>>>> I would expect you to be reporting barometer = sea level pressure >>>>> which is pressure adjusted for temperature and altitude because weather >>>>> stations always report sea level pressures. >>>>> >>>>> Is what you call 'correct' pressure the raw pressure of the instrument >>>>> or a pressure which you have set. Does the station output the raw >>>>> pressure >>>>> or the manually adjusted pressure in the loop records? >>>>> >>>>> >>>>> >>>>> On Friday, 14 February 2020 18:07:15 UTC+2, Dan Blanchard wrote: >>>>>> >>>>>> Andrew, that's a good questions; let me clarify. >>>>>> >>>>>> This issue started when Weather Underground (WU) stopped showing my >>>>>> station on the maps. I found out that was because I was reporting an >>>>>> incorrect barometric 'pressure.' As I dug into the details I found that >>>>>> my *station >>>>>> *was displaying the correct pressure (29.xx) but by the time it got >>>>>> to WU, it was displaying the barometer reading (32.xx) from weewx. This >>>>>> can also be demonstrated by looking at the data displayed at >>>>>> /var/www/html/weewx/index.html >>>>>> (see attachment) so I assume that weewx is taking the pressure from >>>>>> my station and somehow converting it or exchanging it for barometric >>>>>> pressure before it gets uploaded to WU. I just want the pressure from >>>>>> my >>>>>> unit to be what is reported to WU. >>>>>> >>>>>> Side note: I've been running this station for many years on a Windows >>>>>> based system and it has been working fine. So I know the hardware side >>>>>> is >>>>>> working; just something different about how weewx reports pressure (or >>>>>> barometer, or altimiter). >>>>>> >>>>>> Does that help clarify my issue? >>>>>> >>>>>> On Friday, February 14, 2020 at 2:24:31 AM UTC-8, Andrew Milner wrote: >>>>>>> >>>>>>> I am not sure I understand what you think is wrong with the >>>>>>> readings of >>>>>>> Pressure 29.89 >>>>>>> Barometer 32.609 >>>>>>> Altimeter 32.40 >>>>>>> and why you believe something is wrong >>>>>>> >>>>>>> >>>>>>> On Friday, 14 February 2020 05:57:36 UTC+2, Dan Blanchard wrote: >>>>>>>> >>>>>>>> Altitude is 2,320 ft. and the values are in the screen shot on the >>>>>>>> previous post. Did you see that? >>>>>>>> >>>>>>>> On Thursday, February 13, 2020 at 7:16:11 PM UTC-8, Andrew Milner >>>>>>>> wrote: >>>>>>>>> >>>>>>>>> I give up - looks correct to me. >>>>>>>>> >>>>>>>>> have you run from the command line and seen the LOOP and REC data >>>>>>>>> weewx is receiving? >>>>>>>>> >>>>>>>>> what altitude is your station, and what values are you currently >>>>>>>>> getting for pressure, barometer and altimeter? >>>>>>>>> >>>>>>>>> On Thursday, 13 February 2020 22:10:08 UTC+2, Dan Blanchard wrote: >>>>>>>>>> >>>>>>>>>> I don't know, but that makes sense so I did it. I'm still not >>>>>>>>>> getting desired results though. >>>>>>>>>> >>>>>>>>>> On Thursday, February 13, 2020 at 9:38:55 AM UTC-8, Kevin Davis >>>>>>>>>> wrote: >>>>>>>>>>> >>>>>>>>>>> Do you need a space between your minus sign and the adjustment >>>>>>>>>>> value? >>>>>>>>>>> >>>>>>>>>>> On Thu, Feb 13, 2020 at 9:32 AM Dan Blanchard < >>>>>>>>>>> [email protected]> wrote: >>>>>>>>>>> >>>>>>>>>>>> Hey Andrew, will you please look at the attached screen shots >>>>>>>>>>>> and let me know if this looks correct? >>>>>>>>>>>> >>>>>>>>>>>> Do I need to restart (sudo /etc/init.d/weewx restart) after I >>>>>>>>>>>> make these changes? I have and the changes don't seem to be >>>>>>>>>>>> taking >>>>>>>>>>>> effect. Is there something else I need to do? >>>>>>>>>>>> >>>>>>>>>>>> With regard to the barometer and altimeter having the same >>>>>>>>>>>> settings; I have probably misled. They are not exactly the same >>>>>>>>>>>> but they >>>>>>>>>>>> were relatively close to each other compared to the pressure >>>>>>>>>>>> value. Here >>>>>>>>>>>> are the current readings as of now when I run sudo weewxd >>>>>>>>>>>> /etc/weewx/weewx.conf. >>>>>>>>>>>> >>>>>>>>>>>> pressure: 29.98 >>>>>>>>>>>> altimeter: 32.57 >>>>>>>>>>>> barometer: 32.74 >>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>>> On Thursday, February 13, 2020 at 12:07:50 AM UTC-8, Andrew >>>>>>>>>>>> Milner wrote: >>>>>>>>>>>>> >>>>>>>>>>>>> If you have a LaCrosse WS28xx station then according to the >>>>>>>>>>>>> hardware guide the station outputs PRESSURE in weewx terminology >>>>>>>>>>>>> - >>>>>>>>>>>>> regardless of what LaCrosse call it - and weewx should calculate >>>>>>>>>>>>> barometer >>>>>>>>>>>>> and altimeter settings. >>>>>>>>>>>>> >>>>>>>>>>>>> If pressure is incorrect then it can be adjusted as you >>>>>>>>>>>>> specified - by adjusting pressure (not barometer or altimeter) >>>>>>>>>>>>> >>>>>>>>>>>>> Make sure pressure is set to use hardware and barometer and >>>>>>>>>>>>> altimeter are set to use software. >>>>>>>>>>>>> >>>>>>>>>>>>> I am surprised barometer and altimeter are the same values - >>>>>>>>>>>>> have you set the station's altitude in weewx.conf, and have you >>>>>>>>>>>>> specified >>>>>>>>>>>>> software generation for the values? >>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>> On Thursday, 13 February 2020 09:23:27 UTC+2, Dan Blanchard >>>>>>>>>>>>> wrote: >>>>>>>>>>>>>> >>>>>>>>>>>>>> Andrew, are you suggesting that I make a 'correction' entry >>>>>>>>>>>>>> under [StdCalibrate] such as barometer = barometer -2.8 >>>>>>>>>>>>>> assuming that I am >>>>>>>>>>>>>> getting a pressure reading of 30.13 and Barometer and ALtitude >>>>>>>>>>>>>> readings of >>>>>>>>>>>>>> 32.93? >>>>>>>>>>>>>> >>>>>>>>>>>>>> (see attached screenshot) >>>>>>>>>>>>>> >>>>>>>>>>>>>> On Wednesday, February 12, 2020 at 7:42:08 PM UTC-8, Andrew >>>>>>>>>>>>>> Milner wrote: >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> 1. use stdcalibrate section of weewx.conf >>>>>>>>>>>>>>> http://weewx.com/docs/usersguide.htm#StdCalibrate >>>>>>>>>>>>>>> 2. FO station = Fine Offset weather station >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> On Wednesday, 12 February 2020 22:15:48 UTC+2, Dan Blanchard >>>>>>>>>>>>>>> wrote: >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> Andrew, how do I calibrate the pressure in weewx? Also, >>>>>>>>>>>>>>>> what's a FO station? >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> On Tuesday, February 11, 2020 at 8:01:08 PM UTC-8, Andrew >>>>>>>>>>>>>>>> Milner wrote: >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> check that the absolute pressure is correct - I have had a >>>>>>>>>>>>>>>>> FO station which had a dodgy pressure sensor before now. >>>>>>>>>>>>>>>>> Calibrating >>>>>>>>>>>>>>>>> pressure in weewx solved it. >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> >>>>>>>>>>>> -- >>>>>>>>>>>> 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 [email protected]. >>>>>>>>>>>> To view this discussion on the web visit >>>>>>>>>>>> https://groups.google.com/d/msgid/weewx-user/08c79655-b1af-4134-9a2b-82a4f52f051f%40googlegroups.com >>>>>>>>>>>> >>>>>>>>>>>> <https://groups.google.com/d/msgid/weewx-user/08c79655-b1af-4134-9a2b-82a4f52f051f%40googlegroups.com?utm_medium=email&utm_source=footer> >>>>>>>>>>>> . >>>>>>>>>>>> >>>>>>>>>>> >>>> -- >>>> 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 [email protected]. >>>> To view this discussion on the web visit >>>> https://groups.google.com/d/msgid/weewx-user/a24bec68-9459-43f4-8765-933c0c1f2490%40googlegroups.com >>>> >>>> <https://groups.google.com/d/msgid/weewx-user/a24bec68-9459-43f4-8765-933c0c1f2490%40googlegroups.com?utm_medium=email&utm_source=footer> >>>> . >>>> >>>> >>>> -- You received this message because you are subscribed to the Google Groups "weewx-user" group. 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