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Daylight saving change

Posted: Sun 02 Oct 2016 5:15 am
by tassyjim
Running MX on a RPi.
In the land downunder, we put our clocks forward last night.
Instead if somply skipping one hour, my charts went BACK one hour then skipped two hours the second time it reached 2 am.

The data log shows the strange times:
02/10/16,00:50,9.4,81,6.3,5.1,7.2,295,0.0,0.0,1002.8,174.0,14.4,71,3.6,9.0,9.4,0.0,0,0.00,0.00,7.6,0,0.0,315,0.0,0.0
02/10/16,01:00,9.3,82,6.4,6.7,9.7,309,0.0,0.0,1002.9,174.0,14.4,71,5.0,8.5,9.3,0.0,0,0.00,0.00,7.2,0,0.0,270,0.0,0.0
02/10/16,01:10,9.2,82,6.3,7.1,11.2,304,0.0,0.0,1003.0,174.0,14.3,70,5.0,8.3,9.2,0.0,0,0.00,0.00,7.0,0,0.0,315,0.0,0.0
02/10/16,01:20,9.2,82,6.3,7.1,14.8,293,0.0,0.0,1002.9,174.0,14.3,70,8.6,8.3,9.2,0.0,0,0.00,0.00,7.0,0,0.0,315,0.0,0.0
02/10/16,01:30,9.1,82,6.2,3.5,8.6,318,0.0,0.0,1003.0,174.0,14.2,70,2.5,9.1,9.1,0.0,0,0.00,0.00,7.5,0,0.0,315,0.0,0.0
02/10/16,01:40,9.1,83,6.4,2.5,5.0,318,0.0,0.0,1003.1,174.0,14.1,71,1.1,9.1,9.1,0.0,0,0.00,0.00,7.8,0,0.0,315,0.0,0.0
02/10/16,01:50,9.0,83,6.3,7.8,22.0,273,0.0,0.0,1003.0,174.0,14.1,70,17.3,7.9,9.0,0.0,0,0.00,0.00,6.6,0,0.0,225,0.0,0.0
02/10/16,02:00,9.1,83,6.4,16.6,23.4,281,0.0,0.0,1003.1,174.0,13.9,71,8.6,6.6,9.1,0.0,0,0.00,0.00,5.0,0,0.0,270,0.0,0.0
02/10/16,01:10,9.1,83,6.4,7.3,23.4,293,0.0,0.0,1003.1,174.0,13.9,72,6.1,8.1,9.1,0.0,0,0.00,0.00,6.8,0,0.0,315,0.0,0.0
02/10/16,01:20,9.0,83,6.3,7.1,23.4,290,0.0,0.0,1003.2,174.0,13.8,72,2.5,8.0,9.0,0.0,0,0.00,0.00,6.8,0,0.0,270,0.0,0.0
02/10/16,01:30,8.9,84,6.3,7.2,23.4,289,0.0,0.0,1003.2,174.0,13.8,72,8.6,7.9,8.9,0.0,0,0.00,0.00,6.7,0,0.0,315,0.0,0.0
02/10/16,01:40,9.0,83,6.3,9.6,23.4,279,0.0,0.0,1003.1,174.0,13.7,71,8.6,7.5,9.0,0.0,0,0.00,0.00,6.3,0,0.0,270,0.0,0.0
02/10/16,01:50,9.1,83,6.4,10.2,23.4,281,0.0,0.0,1003.3,174.0,13.6,72,5.0,7.5,9.1,0.0,0,0.00,0.00,6.3,0,0.0,292,0.0,0.0
02/10/16,02:00,9.1,82,6.2,11.0,23.4,289,0.0,0.0,1003.3,174.0,13.6,72,3.6,7.4,9.1,0.0,0,0.00,0.00,6.1,0,0.0,270,0.0,0.0
02/10/16,04:10,9.1,82,6.2,6.4,14.8,305,0.0,0.0,1003.5,174.0,13.6,72,6.1,8.3,9.1,0.0,0,0.00,0.00,7.0,0,0.0,315,0.0,0.0
02/10/16,04:20,9.1,82,6.2,6.0,7.2,302,0.0,0.0,1003.5,174.0,13.5,72,6.1,8.4,9.1,0.0,0,0.00,0.00,7.1,0,0.0,315,0.0,0.0
02/10/16,04:30,9.1,82,6.2,7.7,11.2,302,0.0,0.0,1003.6,174.0,13.5,72,8.6,8.0,9.1,0.0,0,0.00,0.00,6.7,0,0.0,315,0.0,0.0
02/10/16,04:40,9.1,82,6.2,8.4,15.8,310,0.0,0.0,1003.7,174.0,13.4,72,8.6,7.9,9.1,0.0,0,0.00,0.00,6.6,0,0.0,315,0.0,0.0
02/10/16,04:50,9.1,82,6.2,8.9,14.8,289,0.0,0.0,1003.6,174.0,13.4,72,13.3,7.8,9.1,0.0,0,0.00,0.00,6.5,0,0.0,315,0.0,0.0
Is it the RPi doing strange things or MX?

From the syslog, it appears that the RPi is OK
Oct 1 23:17:01 cumulus CRON[2960]: (root) CMD ( cd / && run-parts --report /etc/cron.hourly)
Oct 2 00:17:01 cumulus CRON[2981]: (root) CMD ( cd / && run-parts --report /etc/cron.hourly)
Oct 2 01:17:01 cumulus CRON[2998]: (root) CMD ( cd / && run-parts --report /etc/cron.hourly)
Oct 2 03:17:01 cumulus CRON[3016]: (root) CMD ( cd / && run-parts --report /etc/cron.hourly)
Oct 2 04:17:02 cumulus CRON[3052]: (root) CMD ( cd / && run-parts --report /etc/cron.hourly)
Its just one day and by tomorrow morning, I will have forgotten all about it.
But is is curious indeed.

Jim

Re: Daylight saving change

Posted: Sun 02 Oct 2016 7:55 am
by freddie
I find it is better to avoid DST when recording weather data. Having, say, two records for 02:00 in one day (or, at the other end of the year, having an hour's break in your records) doesn't make any sense.

Looking at your particular case, it appears likely that your weather station and computer that MX is running on applied their DST offsets at different times. One of them was in error.

For more info on Cumulus and DST, there is an FAQ article: http://wiki.sandaysoft.com/a/FAQ#How_do ... ng_Time.3F

Re: Daylight saving change

Posted: Sun 02 Oct 2016 2:25 pm
by steve
Cumulus doesn't use the Fine Offset console clock, it just uses the current local time as obtained from the system libraries.