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Wind Speed?

Posted: Sun 17 Jun 2012 1:32 am
by Grumpy Moose
Hi everyone,

I've done some searching, and even posted to another forum, but I can't seem to get my head around the whole wind speed thing. To start off, what first throws me off in the first place is that I get different wind speeds showing on different places on my website... realtime gauges, steel series gauges, and ajax apps.

From what I can tell, the realtime.txt and the realtimegauges.txt files contain different wind speed and gust readings, even though they are both generated by Cumulus under the "real time" function? The wind gauges on the two pages seldom display the exact same number at the same time (the realtime.txt value is also used by the Ajax stuff).

All of these readings (wind speed and gust) also appear to be averages over some time periods, which probably aren't the same, because they seem to lag what the console displays?

There is no such thing as a true "instantaneous" wind speed or gust number that gets passed to a data file and uploaded?

Are these averages due to Cumulus or the data logger?

Are they set somewhere or is there a way to control them?


I guess I really don't have a specific question (yet). I'm just looking for insights, and maybe I can form a coherent question as the discussion progresses.

Thanks in advance for any input from anyone.

Derek

http://www.alaskaweatherwatch.com

Re: Wind Speed?

Posted: Sun 17 Jun 2012 3:04 am
by Grumpy Moose
OK, so I've done a bunch of reading and digging into files and I think I've answered most of my questions.

It appears that the realtime.txt file is using <#wspeed>, while the realtimegauges.txt is using <#wlatest>.

<#wspeed> is supposed to be the 10 min average wind speed output by the Davis console, while <#wlatest> corresponds to the realtime reading of the wind dial on the Cumulus Display. (though I don't understand how Cumulus gets a realtime reading if the Davis Console only provides a 10 min average, but it does appear to be much more responsive than the other reading).

So, the big question is - is there someway to modify the realtime.txt file to output the <#wlatest> value in place of the <#wspeed>. I looked for the source of the realtime.txt file but can't find it anywhere.

Any ideas?

-Derek

http://www.alaskaweatherwatch.com

Re: Wind Speed?

Posted: Sun 17 Jun 2012 4:17 am
by Grumpy Moose
I figured it out..sort of.

I changed the function in the Ajax script that read from the realtime.txt file to use the <#wlatest> value instead of <#wspeed>. Now my homepage updates in "realtime".

However, I don't know how to do the same for the Silverlight Realtime Gauges. It's not in the xml file that I can see.

-Derek

http://www.alaskaweatherwatch.com

Re: Wind Speed?

Posted: Sun 17 Jun 2012 7:25 am
by steve
Davis stations supply two windspeeds, a 3-second average and a 10-minute average (later versions of the firmware also supply a 2-minute average, Cumulus currently doesn't use this).

The 3-second average is available via <#wlatest> and the 10-minute average via <#wspeed>. Both of these are in realtime.txt, see http://wiki.sandaysoft.com/a/Realtime.txt

You can't change what the Silverlight gauges display, but I'm not sure what you would change anyway, as the two dials show the two available wind values; the 'wind speed' dial shows <#wlatest> and the 'wind average' dial shows <#wspeed>.

I can't offer any help for stuff that I didn't write, you'd have to ask the authors of those how to change the parameters they display; but Cumulus does make both values available, as web tags and in realtime.txt.

Re: Wind Speed?

Posted: Sun 17 Jun 2012 1:11 pm
by mcrossley
The SteelSeries realtimegauges.txt file contains three values, #wlatest, #wpseed, and #wgust. All three values are displayed on the wind speed gauge;
#wlatest = pointer & LCD value
#wspeed = green coloured area
#wgust = red coloured area.

Re: Wind Speed?

Posted: Sun 17 Jun 2012 1:47 pm
by steve
mcrossley wrote:#wgust = red coloured area.
And to complete my description of the wind values, <#wgust> is a value calculated by Cumulus rather than supplied by the station. It's the maximum <#wlatest> value (i.e. the station's 3-second readings) over the previous 10 minutes.

Re: Wind Speed?

Posted: Sun 17 Jun 2012 11:52 pm
by Grumpy Moose
steve wrote: Davis stations supply two windspeeds, a 3-second average and a 10-minute average (later versions of the firmware also supply a 2-minute average, Cumulus currently doesn't use this)..
Thanks Steve. That explanation clears things up quite a bit!
steve wrote:The 3-second average is available via <#wlatest> and the 10-minute average via <#wspeed>. Both of these are in realtime.txt, see http://wiki.sandaysoft.com/a/Realtime.txt.
Yes, I found that in the Wiki after poking around a bit. Having both values in the realtime.txt allowed me to figure out a work around for the other software app.


steve wrote:You can't change what the Silverlight gauges display, but I'm not sure what you would change anyway, as the two dials show the two available wind values; the 'wind speed' dial shows <#wlatest> and the 'wind average' dial shows <#wspeed>.
Aha! This is probably the source of my initial confusion. I went and checked - the gauges on my site are labeled differently than yours. Mine are labeled Wind Gust and Wind Speed, Not Wind Speed and Wind Average.. Since my gauge on the left is labeled wind gust, I really didn't notice that it was the one displaying <#wlatest>. I was staring at the one in the center which being the 10 min average obviously changes much more slowly.

I believe I can change the labels via the .xml file?

Thanks

Derek

Re: Wind Speed?

Posted: Sun 17 Jun 2012 11:54 pm
by Grumpy Moose
mcrossley wrote:The SteelSeries realtimegauges.txt file contains three values, #wlatest, #wpseed, and #wgust. All three values are displayed on the wind speed gauge;
#wlatest = pointer & LCD value
#wspeed = green coloured area
#wgust = red coloured area.
Thanks Mark! Knowing what I know now, that display makes a lot more sense to me!

Derek

Re: Wind Speed?

Posted: Mon 18 Jun 2012 7:17 am
by steve
Grumpy Moose wrote:Aha! This is probably the source of my initial confusion. I went and checked - the gauges on my site are labeled differently than yours. Mine are labeled Wind Gust and Wind Speed, Not Wind Speed and Wind Average.. Since my gauge on the left is labeled wind gust, I really didn't notice that it was the one displaying <#wlatest>. I was staring at the one in the center which being the 10 min average obviously changes much more slowly.
Apologies - I'd completely forgotten that I'd changed my labels to be more appropriate for a Davis station.
I believe I can change the labels via the .xml file?
Yes, that's right. Like this:

<gustlabel>Wind Speed</gustlabel>
<windlabel>Wind Average</windlabel>