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VP2 data log interval questions

Discussion specific to Davis weather stations
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superduty
Posts: 27
Joined: Mon 18 Jan 2010 4:45 pm
Weather Station: Davis VP2
Operating System: Windows 7 64 bit

VP2 data log interval questions

Post by superduty » Wed 20 Jan 2010 4:39 am

I am not sure I quite understand the data log interval. I have a VP2. In cumulus I have set the data log interval to 5 minutes. What exactly is that setting for? Clearly the data in cumulus gets updated much more often when using the VP2. It seems the data is updated as often as the Davis console is updated (I think every 2.5 seconds for some functions). So what gets transmitted in the data log?

I have read that the Cumulus data log interval should be set the same as the Davis data logger. How do I set the Davis data logger? Do I have to use WL software for that? Is there anything I need to be aware of when starting up WL if I am running Cumulus? (I actually dont even have WL installed on this new computer).

What are the pros and cons of the different data log interval periods?

How much memory will these data logs use over time? Anyone have a rough estimate? I have a decent size C drive, but I dont want to fill it with WX data.

Is there a way to check what my log interval is on the Davis VP2 (without the WL software)?

TIA

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steve
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Posts: 26717
Joined: Mon 02 Jun 2008 6:49 pm
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Location: Vienne, France
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Re: VP2 data log interval questions

Post by steve » Wed 20 Jan 2010 8:44 am

superduty wrote:I am not sure I quite understand the data log interval. I have a VP2. In cumulus I have set the data log interval to 5 minutes. What exactly is that setting for? Clearly the data in cumulus gets updated much more often when using the VP2. It seems the data is updated as often as the Davis console is updated (I think every 2.5 seconds for some functions). So what gets transmitted in the data log?
It's a "snapshot" of the data, every few minutes. Storing every reading at 2.5 second intervals would consume large amounts of space and wouldn't really give any benefits.
How do I set the Davis data logger? Do I have to use WL software for that?
Yes, you have to use WL.
Is there anything I need to be aware of when starting up WL if I am running Cumulus? (I actually dont even have WL installed on this new computer).
Just don't try to run them both at the same time - unless you use VirtualVP, which would allow that - http://www.softwx.com/weather/virtualvp.html
What are the pros and cons of the different data log interval periods?
A longer log interval will give smaller logs, but will give a coarser set of data - any graphs that you draw or any analysis that you do on the will be less useful. The wind speed is affected the most, other parameters don't tend to change so quickly. The advantage of a longer interval as far as the station logger itself is concerned is that it gives you a longer period that you can go without a PC running before you start to lose data - is has 2500 entries, so at 1-minute intervals that's about 42 hours, at 5-minute intervals it's just over a week, and so on.
How much memory will these data logs use over time? Anyone have a rough estimate? I have a decent size C drive, but I dont want to fill it with WX data.
I have just over three years data for my current station, and at 5 minute intervals it takes up about 13 MB.
Is there a way to check what my log interval is on the Davis VP2 (without the WL software)?
Any data logged by Cumulus which was taken from the logger will be logged at the station logger interval, so if you know a period when logger data was used (because Cumulus was not running at that time) you can see the interval in the Cumulus logs. The default is 10 minutes, so that's probably what yours is if you haven't run WL.
Steve

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