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Cumulus recording false zero temperature

Posted: Wed 17 May 2017 8:03 pm
by hungerdunger
I've had this problem occasionally in the past, but recently it has been happening frequently as the graph shows. Every couple of days the minimum temperature for the first reading after midnight is recorded as zero.

I wonder whether it has anything to do with the fact that I normally shut Cumulus (and my PC) down between about 11.45pm and 12.15am. I already try to avoid the few minutes around midnight in case this is the problem, but surely shutting it down 15 minutes either side of midnight shouldn't affect it.

Any thoughts would be much appreciated.
Temperature.JPG

Re: Cumulus recording false zero temperature

Posted: Wed 17 May 2017 9:09 pm
by steve
It depends on the archive interval in your logger. As the readme.txt says:

"If you close Cumulus down each night, you should avoid closing it
down just before midnight (if you use a midnight end of day),
i.e. when the station will not make any more logger entries before
midnight. This is likely to cause problems when Cumulus starts up
again in the morning, as it will have no 'new' data to read before
it has to do the rollover. In general, it's a good idea to avoid
stopping or starting Cumulus close to the start/end of the day."

So, what interval is your station logger set to?

Re: Cumulus recording false zero temperature

Posted: Wed 17 May 2017 11:14 pm
by hungerdunger
Thanks for getting back Steve, and apologies for not thinking of reading readme.txt first. It's set to 10 minutes.

I'll try to ensure that I leave more than that between shutdown and midnight, and if if it still happens I'll report back.

Re: Cumulus recording false zero temperature

Posted: Thu 18 May 2017 8:50 am
by steve
You need to allow a good margin of error, as the logger entries aren't timestamped and Cumulus has to estimate the timestamps, so allow at least 20 minutes. If it still happens, zip up the diags folder and attach it here, and I'll take a look.