1. It is the change in pressure over, I think, the last 3 hours. Check the template and see what delta is actually being used to populate the field if you want a definitive answer
2. Not necessarily, it may vary slightly due to the floating point libraries doing the conversions from inHg to HPa being applied to real numeric types. Also it depends how often the console updates it's displayed value! 3. You say you have an Ambient station rather than Fine Offset - so what applies to one may not apply to the other. Only read things pertaining to your specific station. The formula used for barometer and altimeter derivations are well documented - either search the forum for this specific answer or check the comments in the code. 4. All weewx calculations are done using floating point with REAL types and no restriction on number of places. If you use MySQL instead of sqlite3 it is possible to specify in the database fields the number of digits to the right - but as far as I know this is not possible in sqlite3. On Tuesday, 30 April 2019 16:02:18 UTC+3, V. Kelly Bellis wrote: > > [image: Seasons' Current Conditions (Parenthetical).PNG] > Under Current Conditions in the Seasons skin, the Barometer value is > appended with a parenthetical value; e.g., 1024.3 hPa(-0.1) > > 1) What is the meaning of the appended parenthetical value? In all > truthfulness, I've only now have just taken note of it as I prepare to make > a calibration adjustment on the display console (Ambient Weather WS-2000), > my first such adjustment since enlisting weewx. My guess is that it shows > the change in pressure when compared to the previous report; e.g., 5 > minutes ago. > > 2) The related question to this pertains to the first value; e.g., 1024.3 > hPa, should it be exactly identical with the value shown on the display > console when the pressure is steady through multiple update intervals? > > I've read <http://weewx.com/docs/usersguide.htm#pressure_calibration> > that weewx receives 'pressure' from FineOffset hardware and then calculates > 'barometer' values. This brings up two more questions. > > 3) What is the formula that is being used and to how many places to the > right of the decimal is this formula applied? > > 4) Loop packets suggest that 'pressure' is being reported by the hardware > in units of inHg to 2 significant digits, is this a false assumption? and > how might it be proven? > > pi@raspberrypi:/etc/weewx $ sudo /etc/init.d/weewx stop > [ ok ] Stopping weewx (via systemctl): weewx.service. > pi@raspberrypi:/etc/weewx $ sudo weewxd weewx.conf > LOOP: 2019-04-28 10:51:20 EDT (1556463080) altimeter: 29.8717169546, > appTemp: 42.072810622, barometer: 29.8843336142, cloudbase: 3250.42822233, > dateTime: 1556463080, dewpoint: 33.8944955053, heatindex: 47.5, humidex: > 47.5, inDewpoint: 41.4872761332, inHumidity: 39, inTemp: 67.3, maxSolarRad: > 815.85703395, outHumidity: 59, outTemp: 47.5, pressure: 29.71, radiation: > 881.07, rain: 0.0, rainRate: 0, usUnits: 1, UV: 8, windchill: 46.1399181728, > windDir: 290, windGust: 4.5, windSpeed: 3.8 > LOOP: 2019-04-28 10:51:36 EDT (1556463096) altimeter: 29.8717169546, > appTemp: 42.2517904021, barometer: 29.8843336142, cloudbase: 3154.86029954, > dateTime: 1556463096, dewpoint: 34.3149943656, heatindex: 47.5, humidex: > 47.5, inDewpoint: 41.4872761332, inHumidity: 39, inTemp: 67.3, maxSolarRad: > 816.299633379, outHumidity: 60, outTemp: 47.5, pressure: 29.71, radiation: > 878.37, rain: 0.0, rainRate: 0, usUnits: 1, UV: 8, windchill: 46.3046187182, > windDir: 307, windGust: 4.5, windSpeed: 3.6 > LOOP: 2019-04-28 10:51:52 EDT (1556463112) altimeter: 29.8717169546, > appTemp: 41.6321945021, barometer: 29.8843336142, cloudbase: 3154.86029954, > dateTime: 1556463112, dewpoint: 34.3149943656, heatindex: 47.5, humidex: > 47.5, inDewpoint: 41.4872761332, inHumidity: 39, inTemp: 67.3, maxSolarRad: > 816.741118563, outHumidity: 60, outTemp: 47.5, pressure: 29.71, radiation: > 877.51, rain: 0.0, rainRate: 0, usUnits: 1, UV: 8, windchill: 45.478419953, > windDir: 312, windGust: 5.8, windSpeed: 4.7 > LOOP: 2019-04-28 10:52:08 EDT (1556463128) altimeter: 29.8717169546, > appTemp: 42.6460787021, barometer: 29.8843336142, cloudbase: 3154.86029954, > dateTime: 1556463128, dewpoint: 34.3149943656, heatindex: 47.5, humidex: > 47.5, inDewpoint: 41.4872761332, inHumidity: 39, inTemp: 67.3, maxSolarRad: > 817.181491045, outHumidity: 60, outTemp: 47.5, pressure: 29.71, radiation: > 874.46, rain: 0.0, rainRate: 0, usUnits: 1, UV: 8, windchill: 47.5, windDir: > 291, windGust: 4.5, windSpeed: 2.9 > LOOP: 2019-04-28 10:52:24 EDT (1556463144) altimeter: 29.8717169546, > appTemp: 40.9662707821, barometer: 29.8843336142, cloudbase: 3060.68950083, > dateTime: 1556463144, dewpoint: 34.7293458799, heatindex: 47.5, humidex: > 47.5, inDewpoint: 41.4872761332, inHumidity: 39, inTemp: 67.3, maxSolarRad: > 817.620605418, outHumidity: 61, outTemp: 47.5, pressure: 29.71, radiation: > 874.46, rain: 0.0, rainRate: 0, usUnits: 1, UV: 8, windchill: 44.6901761734, > windDir: 310, windGust: 9.2, windSpeed: 6.0 > LOOP: 2019-04-28 10:52:40 EDT (1556463160) altimeter: 29.8717169546, > appTemp: 39.4917723021, barometer: 29.8843336142, cloudbase: 3154.86029954, > dateTime: 1556463160, dewpoint: 34.3149943656, heatindex: 47.5, humidex: > 47.5, inDewpoint: 41.4872761332, inHumidity: 39, inTemp: 67.3, maxSolarRad: > 818.058803625, outHumidity: 60, outTemp: 47.5, pressure: 29.71, radiation: > 874.46, rain: 0.0, rainRate: 0, usUnits: 1, UV: 8, windchill: 43.5112234785, > windDir: 308, windGust: 11.4, windSpeed: 8.5 > LOOP: 2019-04-28 10:52:56 EDT (1556463176) altimeter: 29.8817634304, > appTemp: 40.8999448021, barometer: 29.8943922927, cloudbase: 3154.86029954, > dateTime: 1556463176, dewpoint: 34.3149943656, heatindex: 47.5, humidex: > 47.5, inDewpoint: 41.665600342, inHumidity: 39, inTemp: 67.5, maxSolarRad: > 818.495940296, outHumidity: 60, outTemp: 47.5, pressure: 29.72, radiation: > 874.09, rain: 0.0, rainRate: 0, usUnits: 1, UV: 8, windchill: 44.6901761734, > windDir: 257, windGust: 6.9, windSpeed: 6.0 > > > Thank you very much for any reply. > > Kind regards, > > Kelly > > > -- You received this message because you are subscribed to the Google Groups "weewx-user" group. 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