VP 2 console clock losing time

[Touchtone]

If I synchronize the the Davis console to computer clock time in the Cumulus configuration, the console clock loses time, in fact well over 15 seconds fairly quickly.
If I don't have it synchronized it doesn't lose time at all.
I am comparing the computer time shown up on the top RH side of the Cumulus screen, with the console & a watch to check whether Davis is losing time. With synchronizing it does & without synchronizing it doesn't.
Has anyone got any clues on this one & are there problems running without computer clock synchronizing.

[BCJKiwi]

Cumulus will reset a Davis Console clock whenever Cumulus is restarted.

So if there is a slight difference in the time or a small delay, then the two may be slightly different.

But do you mean it keeps losing time - i.e. the difference just keeps getting bigger?

As long as Cumulus and the console keep running there won't be any issue, however, if Cumulus is off for a while and has to download logged data, it will either miss some or download some it already has as when loading data from the logger (instead of 'realtime') it works off the time stamps of the logger data which of course come from the console.

I'm in the Southern Hemisphere and the Davis Consoles can't manage daylight saving time changes here. So the Davis clock was an hour different. I just restarted Cumulus to get it right and Cumulus downloaded 11 logged data items (5 min intervals) which it already had. Of course if the time had shifted the other way I would have missed an hour's data!

So reset Cumulus when the clocks move.

If having the setting on in Cumulus is a problem then turn it off and manually set the Console to match Cumulus.

[steve]

The function for setting the clock from software only allows a resolution of one minute, so Cumulus has to round the current PC time to the nearest minute. But it always rounds down, because there are problems associated with having the console clock later than the PC clock.

[BCJKiwi]

Good to know Steve - so just restart Cumulus on the minute.

[Touchtone]

Thanks for the replies. I will probably make sure the console clock is slightly ahead of the PC clock, so avoid having the console clock later than the PC one.
Fortunately we don't have daylight saving here so I don't have that problem.

[steve]

You know, now I've read that again I think I may have it the wrong way round. I think it may be bad to have the PC clock later than the console clock. I'll have to have a think about that and possibly change Cumulus.

[Touchtone]

Hi Steve. I will be very interested to find out what you eventually come up with. My thinking is that probably the console clock should lead the PC clock as the information in the console would be relayed to Cumulus after the console had updated in own information. Of course I am certainly no expert on this, so don't take my thinking as gospel.
Best regards. Bligh.

[Touchtone]

Hi Steve. Just thought you may be interested that the WeatherLink program can be used to set the console date & time & this can be used to set the PC clock to the same time as the console clock, not the other way around. In other words you can't use the PC to set the console clock. My WeatherLink is version 6.0.2 & is the current one as far as I know.
Adjusting PC time setting in WL is not automatic, you have to do it manually if you decide to do it, but I don't use it. It is handy to be able to reset the console clock from WL though.
Regards. Bligh.

[steve]

Just thought you may be interested that the WeatherLink program can be used to set the console date & time & this can be used to set the PC clock to the same time as the console clock, not the other way around. In other words you can't use the PC to set the console clock.

The interface available to Cumulus for reading the console clock is also to the nearest minute, so this would have the same issue as doing it the other way around, in Cumulus.

[Touchtone]

Does Cumulus, if "synchronize console to PC time" is selected, only set the console clock to PC time when it is first starts or does it update the console from time to time if it's running continuously.
The reason I am asking this is that if it doesn't synchronize from time to time in continuous mode, then time synchronization can get well out of sync over a period. Most console clocks, & indeed all battery powered clocks either gain or lose time, & that includes ones running off AC adapters as well.

[steve]

It only does it at start up currently. It does need to do it more often, and I'm looking into the best way of doing that without disrupting the normal data reading. I'm thinking that doing it once a day at around 3 or 4 am should be sufficient?

[BCJKiwi]

Maybe 02:01am as Daylight saving usually changes at 2am?

[steve]

Maybe 02:01am as Daylight saving usually changes at 2am?

In places where DST starts at 0200, so the clock jumps from 0200 to 0300, the clock wouldn't get set (but only for one day a year). That's why I'm thinking avoid all of that complication and do it at 0400.

[BCJKiwi]

I have not thought it through fully but am concerned at the possibility of losing data.

In the Southern Hemisphere we have just moved from 'daylight saving' (as it is known here - dumb terms people come up with - or summer time as it is more widely known elsewhere) to standard time as we are now heading into winter. The clock on the PC changed at 2am and the console time was not reset until cumulus was restarted a few days later.
On restart, 1 hours' data was read twice. At the other change, there will be a 1hour gap.

I suppose it does not really matter when this happens as both the double up and the gap will occur whenever the change is made. Provided Cumulus and the console keep running for at least an hour after the console time is changed and/or Cumulus is restarted, the data in the logger will be in sync for an hour so a restart of Cumulus after that will read current data without a gap or double up. Can the logger actually cope with two sets of data with the same time stamp?, or does it work on an index/counter?

[mcrossley]

Doesn't the console automatically switch DST (for US, Europe, and most of Austrailia) ?