WXforum.net
Weather Software => WeatherLink/weatherlink.com by Davis Instruments => Topic started by: weathergirl on December 01, 2006, 08:32:22 AM
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I am using the Weatherlink serial data logger. Does the datalogger's data need to be cleared occasionally or will the new data overwrite the old?
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No. The data logger is a circular buffer. Once it fills up the oldest data gets overwritten by new data.
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Thanks Tom :)
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I am using the Weatherlink serial data logger. Does the datalogger's data need to be cleared occasionally or will the new data overwrite the old?
I believe the buffer in the datalogger itself overwrites itself continually; however, the data stored in the WeatherLink directory of your hard drive (if you are using WL), continues to accrue until it is moved, stored, or you run out of space :)
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Understood, thanks AW :)
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Of possible interest, if I understand correctly... as the datalogger fills up, it will take longer and longer to download at each interval, because the program must determine what is new data.
So... if you use the option to clear the logger after each download, in theory it should maintain the fastest download speed possible.
I've never let mine fill up, so I don't know how much of that speed difference would be more academic than practically useful...
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That's an interesting point, actually. I have noticed that my weather programs take a very long time to start because they are downloading data. Where would I find the option to clear the data logger?
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Can't remember exactly... wait, of course, I've got the manual for Weather Link on my work computer!! :)
Under "Setup", "Station Config" (in WeatherLink), there's a checkbox for Download Options -- "Clear archive memory after download"
(From the manual)
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You may have the software automatically clear the archive memory whenever it downloads data. Clearing after each download will decrease the time it takes to download because there will be less “accumulated” data in the archive memory. Not clearing after each download allows you to download data into multiple databases (if more than one person uses a
single weather station, for example). To clear data in the archive memory
after each download, select the check box.
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Also of possible interest:
(From the manual)
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The archive memory is the weather information storage area in the WeatherLink itself. At each archive interval the WeatherLink stores one record to archive memory. The WeatherLink has room in the archive memory for approximately 1 day of weather data for each minute in the archive interval. For example, if you use the 1 minute archive interval, the WeatherLink may store approximately 1 day of data.
If you use the 30 minute archive interval, the WeatherLink may store approximately 30 days of data. If you use the 2 hour archive interval (120 minutes), the WeatherLink may store approximately 120 days of data.
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If you use 1 minute intervals, and you lose power to your computer for more than a day, you will lose data... I used to use 1 minute intervals, now I have it set to 5 minutes. There's a thread somewhere on this issue...
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Straight from the Davis Weatherlink documentation.
Data Logger Storage Capacity
This is the amount of time it takes to completely fill the archive memory:
Archive Interval Setting Data Storage Capacity (time to fill memory)
1 Minute 1.7 days (42 hours, 40 minutes)
5 Minute 8.8 days
10 Minute 17.7 days
15 Minute 26.6 days
30 Minute 53.3 days
60 Minute 106.7 days
120 Minute 213.3 days
Data is not erased from the archive when you download. The Vantage Pro
and Vantage Pro2 consoles are smart enough to send only the data
accumulated since the last time you downloaded. The data remains in the
data logger as a backup until you intentionally clear the memory, reset
the archive interval, or the archive memory is full.
Since this backup data is stored on the logger, you can restore edits
you have made near the end (the more recent data) of the database.
Delete the last records from the database file and download again. If
you want to see how many records are stored in the archive memory,
download into an empty database. The entire archive is downloaded.
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Thanks guys. I don't use the Weatherlink software at the moment, but I do run VWS and WD. Can I clear the datalogger with either of those programs?
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In VWS, under Vantage/Weatherlink settings you will see a check box in the bottom left corner of that screen, "Clear archive after download". Just check the box and you are set to go.
Bob
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Ok, thanks Bob.