Il giorno martedì 27 novembre 2018 05:56:43 UTC+1, gjr80 ha scritto: > OK, let's do the maths... > > Assume the default rain window (rain_period) of 900 seconds (15 minutes). > WeeWX will calculate loop rainRate as sum of loop rainfall over the last 900 > seconds * 3600/900. > > First rain event is loop packet at 08:40:27 where 0.11811023622 fell. > Previous rainRate was 0.0 so we know no rain fell in the previous 15 minutes. > weeWX would calculate rainRate as 0.11811023622*3600/900 = 0.472440945. Log > indicates 0.472440944882. > > Loop packets from 08:40:28 to 08:51:15 inclusive have no recorded rainfall so > rainRate remains at 0.11811023622*3600/900 = 0.472440945. Log indicates > 0.472440944882 in each loop packet. > > Loop packet 08:51:40 has a rain event that includes 0.11811023622 rainfall. > weeWX would calculate rainRate as (0.11811023622+0.11811023622)*3600/900 = > 0.94488189. Log indicates 0.944881889764. > > No further loop rainfall occurs so loop rainRate remains 0.944881889764 for > the rest of the screen capture. Had the screen capture continued and no > further rainfall occurred I would expect loop rainRate would decay to > 0.472440944882 in the first loop packet after 08:55:27. rainRate would drop > to 0.0 in the first loop packet after 09:06:40. > > rainRate in archive records works a little differently, in particular when > software record generation is used (it's not clear what is being used in this > case but I expect it will be software record generation). When software > record generation is used the archive record rainRate is taken as the average > of the loop rainRate values seen during the archive period. In this case the > first archive record at 08:40:00 had seen no rain and rainRate = 0. The > screen capture indicates 0.0 > > The 08:42:00 archive record would have seen loop packets at 08:40:15, > 08:40:27 and 08:40:28 with respective rainRate values of 0, 0.472440944882 > and 0.472440944882. The average of these is (2*0.472440944882)/3 = > 0.31496063. The screen capture indicates 0.31496063. > > The 08:44:00 archive record will have seen the loop rainRate value of > 0.472440944882 seven times. The average being 0.472440944882. The screen > capture indicates 0.472440944882. > > The 08:46:00 archive record saw loop rainRate of 0.472440944882 three times > so the resulting average is 0.472440944882. The 08:48:00 archive record saw > loop rainRate of 0.472440944882 four times so the resulting average is > 0.472440944882. The 08:50:00 archive record saw loop rainRate of > 0.472440944882 once so the resulting average is 0.472440944882. These values > agree with the screen capture. > > The 08:52:00 archive record saw loop rainRate of 0.472440944882 three times > and 0.944881889764 once so the resulting average is 0.590551181102. The > screen capture indicates 0.590551181102. > > The 08:54:00 archive record saw loop rainRate of 0.944881889764 three times > so the resulting average is 0.944881889764. The screen capture indicates > 0.944881889764. > > So the upshot is given the rain values in the loop packets weeWX is > calculating loop and archive rainRate exactly as it should. Where I believe > the error lies is in the loop rain values as mentioned by the OP in post #3. > If we look at the first rain event the rain_total jumps from 63.0 to 63.3 yet > rain is recorded as 0.11811023622; we would have expected 0.3 ie the simple > difference between success rain_total values. Also, if we multiply > 0.11811023622 by 2.54 we get 0.3. So clearly we have a cm to inches > conversion occurring somewhere that is not needed. My quick look at the SDR > driver did not reveal anything, probably needs Matthew's eye! > > Gary > > > On Tuesday, 27 November 2018 01:49:13 UTC+10, Andrew Milner wrote: > > I cant get anything like the given rainrates for the period of the log > > > A longer log extract is definitely needed!! > > > > > On Monday, 26 November 2018 10:39:48 UTC+2, gjr80 wrote:Hi, > What makes you say the rainRate is wrong? By default weeWX calculates > rainRate over a 15 minute sliding window, your screen capture covers > approximately 16 minutes with at least two rain events so seeing a non-zero > rain rate in all packets/records after the first rain event is expected. You > can change the window size by setting the rain_period config option in > weewx.cnf: > [StdWXCalculate] > .... > [[Calculations]] > .... > rain_period = xxx > .... > Where xxx is the rain_period to be used in seconds. You will need to restart > WeeWX or do a config reload for the new setting to take effect. > Gary
After an year I've tried again to work with Weewx but I've same problem with rain 😢 can I do some things?! Thanks!!! -- 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/5d855dee-4945-4eb3-b744-99925e6e1ad8%40googlegroups.com.
