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] <javascript:>> > 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] <javascript:>. > 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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