Daylight Saving

[vetgmc]

How is it advised that we manage daylight saving using Cumulus?

[steve]

Cumulus 1 just timestamps everything at the clock setting of the PC. This means that unfortunately you get either a 'missing' or 'duplicate' set of records when the clocks change. Ideally, you'd keep your PC and weather station clock on a fixed time to avoid the issue, but other than that there isn't an easy way around it.

Cumulus 2 timestamps everything with UTC, so avoiding the problem as far as logging is concerned, but this still leaves issues with what to do when displaying the data...

[vetgmc]

I saw a post elsewhere on the forum that asomeone had trouble using Cumulus 2 with WH1091. Is that resolved now & can I download Cumulus 2 to address this issue?

[steve]

Cumulus (1 and 2) should work with the WH-1091, as far as I can tell. You're quite welcome to download and try Cumulus 2, but it's still an 'alpha' and isn't suitable for use as an alternative to Cumulus 1 yet.

[dane]

Checked my dayfile and Oct-monthfile.
Didn't find any duplicate or missing records at the time of change to winter time at 3am.
Maybe the reason is: my PC was switched off at the time. So maybe the weather station handled the situation "automagically" ?
And maybe that would be the advice to give: turn off your PC during the hours of change
(except: next time we shall not be running Cumulus 1 )

[vetgmc]

Thanks for the responses. the idea of turning off teh computer raises the issue of what happens to data for teh eriod the PC is off (or if the programme isn't running. Does the programme gather the missing data from the weather station whern it is turned back on? I thought I read in the help file that it coudn't do that.

[steve]

Didn't find any duplicate or missing records at the time of change to winter time at 3am.
Maybe the reason is: my PC was switched off at the time.

Yes, the result is different if your PC is switched off at the time. It also depends on the type of weather station and whether it timestamps logger entries (Fine Offset don't).

If you think about it, you almost certainly do actually have missing records - the hour after you switched off, I think. If you count how many hours worth of data you've got logged betweeen switching off and on again, and then count how many actual hours there were, you probably have an hour missing.

Say you switched off at 2300 (summer time) on Saturday and powered on at 1100 (winter time) on Sunday. Cumulus will have 12 hours of data logged, but there were actually 13 hours elapsed time.

[steve]

Thanks for the responses. the idea of turning off teh computer raises the issue of what happens to data for teh eriod the PC is off (or if the programme isn't running. Does the programme gather the missing data from the weather station whern it is turned back on? I thought I read in the help file that it coudn't do that.

Yes, for stations with loggers, it catches up when you start it up. It didn't always do that, so I may have forgotten to amend some of the documentation. If you come across it again, please let me know and I'll correct it.

[bordersweather]

Well I saw an issue that happened that I don't think got reported.....

Sunrise and Sunset did not automagically change and required a restart of cumulus and a forced web update in order to correct cumuluswebatgs.php

[6719jason]

Well I saw an issue that happened that I don't think got reported.....

Sunrise and Sunset did not automagically change and required a restart of cumulus and a forced web update in order to correct cumuluswebatgs.php

I can indeed confirm that, a restart and forced web update was required to solve the issue.

[steve]

That's interesting - how long did you leave it? The sunrise and sunset times only get updated once an hour (or at restart), so if the clock on your PC changes just after the hour (as I suspect it probably does), then it will take until the next hour before the sunrise and sunset times get updated.

[6719jason]

I think I left it nearly an hour, if not past the hour. Is there a log at all somewhere so I can double check?

[steve]

No, only the current sunrise and sunset times are stored, they're not logged anywhere. It's a shame this wasn't mentioned earlier, because mine was still running until some time yesterday, so I could have checked whether mine had changed. I have to say that I'm reasonably confident that it does work OK and changes to the correct time at the top of the next hour. There's no difference between what it does at start up and what it does each hour.

I could run a check in a VM with the clock set back to before the change. Or someone else could

Edit: I think I misunderstood your question! The diags folder is effectively a log of your last 10 start ups, so you could look in there to see what time you restarted Cumulus.