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Cumulus readings out of sync with station and normal clock

Posted: Fri 06 Apr 2012 5:54 pm
by cwiltshire
I have an issue with the synchronisation of readings between Cumulus and the station which is frustrating.

I have set the station to read every ten minutes on the hour, hr+10, hr+20 etc, and Cumulus to do likewise.

Occasionally the station will wander off to say hr.01, hr.11; hr:02 hr:12 etc and Cumulus will follow. I can reset the station back to the clock pattern but Cumulus can continue to gain for no apparent reason even though I consistently take readings on the normal clock 10 minute interval.

At present the station is reading as it should but Cumulus is now completely out of phase: its last readings which should have been 18:20 and 18.30 have been logged at 18.25 and 18:35.

Can anyone suggest how I get Cumulus back into line please?

Thanks

Chris

Re: Cumulus readings out of sync with station and normal clo

Posted: Fri 06 Apr 2012 6:44 pm
by steve
This is presumably data from the logger, read by Cumulus when it starts up? The station doesn't timestamp its data, so there's no way that Cumulus knows exactly when the data was logged. It always uses the PC clock, and has to try to work out when the data was logged by using the time when it starts up and working backwards through the logger entries calculating the timestamp based on the archive interval.

It is therefore not actually possible to synchronise Cumulus with the station. The best you can hope for is to keep the station clock set to the same time as the PC, and then you should then only ever see a difference between the station and Cumulus of a minute or two. But this wouldn't account for a difference of five minutes, so perhaps I have misunderstood the issue you are reporting, if so please clarify, and also tell me what version/build of Cumulus you are using. If the data is from the logger, if you zip up the diags folder and attach it, I can see where Cumulus is getting the timestamps from.