On my side, I have looked at the CPU utilization on my raspberry Pi 3B+. I have the mqtt service service installed, so at each loop all data of the packet are sent to the mqtt broker.
With mqtt and when calculations of the sunshine threshold is done for each loop packet, the total CPU utilization of python3 is about 0.75% With mqtt and without calculation of sunshine threshold : 0.5% of total CPU. So one can estimate that 0.25 % of total CPU is needed for the calculation of the threshold value for each LOOP packet. > Le 9 juin 2022 à 22:26, 'Peter Fletcher' via weewx-user > <[email protected]> a écrit : > > After some experimentation, I found that the radiation value in the VP2 LOOP > packets does, indeed, normally change every 50-52 seconds, but, perhaps about > a fifth of the 'gaps' are a multiple of that time - most often 100+ or 150+ > seconds, but occasionally more than that (I saw one 250+ second 'gap'). I saw > this under conditions of variable sunshine and clouds when it seemed unlikely > that the actual radiation value would have been precisely constant for that > length of time, so I am not sure exactly what is going on. In any event, I am > revising the code I am using on the basis of doing the threshold calculation > when the radiation level changes, but at least every minute, if it remains > constant for more than the normal 50-52 seconds.. > > On Sunday, June 5, 2022 at 12:33:47 PM UTC-4 [email protected] wrote: > I think it is also OK to do an average for every 30 seconds. It depends also > on the weather station used. > For instance, a Davis Vantage Pro 2 ISS transmits an updated solar > radiation value every 50 to 60 seconds. So with this weather station, even a > 1 minute average would not be very different since anyway the solar > radiation values of the LOOP packet are the same for at least 50 seconds.! > > >> Le 5 juin 2022 à 18:02, 'Peter Fletcher' via weewx-user >> <[email protected] >> <applewebdata://E7D0CAFE-B2F1-4647-81D5-9CF5075D8ACD>> a écrit : >> > >> I chose to average the LOOP radiation readings and only to do the threshold >> calculation and make the sun/no sun determination every 30 seconds because I >> thought doing it on every LOOP might overload LOOP processing (I am running >> weewx on a Pi 3B, which is also doing a few other things which use the CPU). >> If this is an unnecessary concern, as it may very well be, your modified >> code is much cleaner than mine. >> >> On Saturday, June 4, 2022 at 12:41:08 PM UTC-4 [email protected] >> <http://gmail.com/> wrote: >> It is a very good idea to calculate the sunshine duration for each LOOP >> packet and sum these values to make the final archive sunshine duration. I >> have modified my script accordingly : >> https://github.com/Jterrettaz/sunduration >> <https://github.com/Jterrettaz/sunduration>. >> The logic is the following : for each received LOOP packet, the radiation >> is compared to a calculated threshold. If the radiation is above the >> threshold value, the sunshine time for the LOOP packet is equal to the time >> elapsed between the previous loop packet and this packet (most of the time >> 2 seconds with a Vantage Davis Pro). >> The final archive sunshine duration is the sum of all the LOOP value within >> the archive period. >> Le vendredi 3 juin 2022 à 21:59:36 UTC+2, Peter Fletcher a écrit : >> That makes some sense when you are getting data from an 'external' sensor, >> though there are (IMHO) simpler ways of doing it. weewx already has access >> to the LOOP radiation data from the VP2, so handling the processing and data >> storage within weewx makes more sense to me in this case. >> >> On Friday, June 3, 2022 at 3:24:23 PM UTC-4 vince wrote: >> On Friday, June 3, 2022 at 11:17:00 AM UTC-7 Meteo Oberwallis wrote: >> if the interval of Weewx and the data logger is set to 10 minutes, I would >> have liked to read the value of the solar sensor every minute and then write >> it into a separate .sdb database as possible sunshine. >> >> Personally I'd use an external program called via cron and posting a message >> to a MQTT topic. Have weewx subscribe to that topic to get the data into >> your db. >> >> This is how I used to get my DS18b20 temperature sensor data into weewx. >> >> > >> -- >> You received this message because you are subscribed to a topic in the >> Google Groups "weewx-user" group. >> To unsubscribe from this topic, visit >> https://groups.google.com/d/topic/weewx-user/19ylVTRqbh4/unsubscribe >> <https://groups.google.com/d/topic/weewx-user/19ylVTRqbh4/unsubscribe>. >> To unsubscribe from this group and all its topics, send an email to >> [email protected] >> <applewebdata://E7D0CAFE-B2F1-4647-81D5-9CF5075D8ACD>. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/weewx-user/0e631671-0a74-4963-9f1c-e5f81bc7c366n%40googlegroups.com >> >> <https://groups.google.com/d/msgid/weewx-user/0e631671-0a74-4963-9f1c-e5f81bc7c366n%40googlegroups.com?utm_medium=email&utm_source=footer>. > > > -- > You received this message because you are subscribed to a topic in the Google > Groups "weewx-user" group. > To unsubscribe from this topic, visit > https://groups.google.com/d/topic/weewx-user/19ylVTRqbh4/unsubscribe > <https://groups.google.com/d/topic/weewx-user/19ylVTRqbh4/unsubscribe>. > To unsubscribe from this group and all its topics, send an email to > [email protected] > <mailto:[email protected]>. > To view this discussion on the web visit > https://groups.google.com/d/msgid/weewx-user/f0ecc86f-a615-4a24-a43f-ee0d3963b8adn%40googlegroups.com > > <https://groups.google.com/d/msgid/weewx-user/f0ecc86f-a615-4a24-a43f-ee0d3963b8adn%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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