On Sat, 12 Feb 2011 02:27:32 -0800 (PST), prodata wrote:

On Feb 12, 9:36*am, Paul Hyett wrote:
At least most manufacturers have finally realised that USB exists.

Although I think that it's generally accepted that for real-time data
feeds in real world situations serial (or possibly Ethernet) is still
slightly more robust than USB. (Or serial to the PC location and then
a serial-to-USB adapter at the PC.) USB is always going to be more
prone to noise and RFI than serial. Also USB leads need to be as
direct and as short as possible for robust operation whereas serial is
much more flexible.) Of course if you just want to download logged
data once a day/week/whatever then USB is fine.


Whenever I peruse mid-range weather stations though, they seem to have
ridiculously low internal data storage.

That's not true of the Davis loggers, for example (especially not of
the new Envoy8X with 32x the memory of the standard Weatherlink
loggers and which can log a year's worth of data at 15min intervals
and - I haven't checked this but by extrapolation - 8 years' worth at
a 2hr interval). If anyone hasn't come across the Envoy8x so far,
there's a preliminary description on our website at:

http://www.weatherstations.co.uk/envoy8x.htm

What's the point of having the
capability for storing at say, 1 minute intervals, if you only have
enough capacity for 24 hours at that resolution?

Just in passing, I'm never quite sure why anyone would want to use a 1-
minute interval (unless I guess you're keen to capture those rare
frontal passages where the detailed pressure profile is of interest).
The only weather parameter that generally changes very frequently is
wind speed and direction and 1 minute is far too long to capture any
real structure in the wind data - you would need logging at 3-second
intervals to do justice to wind gust data. Personally I think that
logging at 5- or 10-minute intervals strikes a good balance between
decent granularity in the data record while not submerging the user in
reams of highly redundant data that you tend to get with 1-minute
logging. And on a logging architecture like the one Davis use, you'll
still log values for eg the max gust speed, max rainfall rate etc,
irrespective of the logging interval chosen. But each to their own.

John Dann
www.weatherstations.co.uk

I used to use 15min intervals on my VP1 but switched to 30mins when I went
to New Zealand for an extended holiday. On 15 mins I could only hold about
28 days data which was not enough. To be fair the data capacity is
perfectly adequate athough it would be nice to have a bit more on the
standard Davis loggers.

I found that Maplins serial to USB adaptor works well on both Windows XP
and Vista and presumably Windows 7 as well.

As a final comment I have had my Davis VP1 for almost 10 years and in that
time I have had to sort out the anemometer reed switch twice and the
rainguage reed switch once. The external humidity sensor is starting to
deteriorate so I may well have do something there soon. I have no
complaints at all about the overall performance of the station.


Alan Gardiner
Chiswell Green, St Albans
101m ASL
12/02/2011 15:11:04
https://sites.google.com/site/alangardinersinfo/