Max wind gust different in Cumulus

DaveNZ · **Posted:** Sun Dec 20, 2009 4:01 am

hello Steve,

Today my weather station has recorded a peak gust of 39km/h at 4:09pm and again at 4:11pm, but while cumulus was running and collecting live data, it says the daily high gust is 35km/h.

steve · **Posted:** Sun Dec 20, 2009 10:50 am

I can't explain that, assuming it was actually running at those times. It's possible that the DLL doesn't gather absolutely every wind reading and occasional ones get missed, given that they update so quickly and the DLL is quite slow at collecting the data, it just does a single 'LOOP 1' request when asked for the data, if that means anything to you; so I guess it's inevitable that some get missed.

steve · **Posted:** Mon Dec 21, 2009 11:28 am

It's occurred to me that you might be able to reduce the possibility of missed wind gusts by decreasing the VP2SleepInterval via the cumulus.ini file. I came up with 500 ms based on how long it took to read the data on my system. It may take longer on yours so a shorter sleep may be appropriate.

DaveNZ · **Posted:** Wed Dec 30, 2009 1:45 am

steve wrote:

It's occurred to me that you might be able to reduce the possibility of missed wind gusts by decreasing the VP2SleepInterval via the cumulus.ini file. I came up with 500 ms based on how long it took to read the data on my system. It may take longer on yours so a shorter sleep may be appropriate.

I can't find a VP2SleepInterval in the cumulus.ini file...

PaulMy · **Posted:** Wed Dec 30, 2009 2:37 am

I found the following in the readme.txt file in the Cumulus folder after installing Cumulus v. 1.8.8

Installation:
If you use virtualvp, it is recommended that you edit the cumulus.ini file (created after you run Cumulus for the first time) and in the (Station) section, add a line:
VP2SleepInterval = 1100

and possibly this needs to be added to yours if it is not already there, and perhaps change the value as per Steve's suggestion.

steve · **Posted:** Wed Dec 30, 2009 12:03 pm

...and all of the cumulus.ini settings are of course documented in the wiki :roll:

gemini06720 · **Posted:** Wed Dec 30, 2009 1:26 pm

steve wrote:

...and all of the cumulus.ini settings are of course documented in the wiki :roll:

Steve, it might be time that you add a line such as 'Please read the Wiki before asking a question' to the top of the forums where the latest releases of Cumulus are displayed... :twisted:

But then again, who reads that line anyway... :mrgreen:

DaveNZ · **Posted:** Wed Dec 30, 2009 8:59 pm

I don't see how that's supposed to help me, since that parameter is not in my cumulus.ini anyway.

I added it in and since the default is apparently 500, I added the line VP2SleepInterval=300
I hope that's a reasonable number?

gemini06720 · **Posted:** Thu Dec 31, 2009 10:25 am

DaveNZ wrote:

I don't see how that's supposed to help me, since that parameter is not in my cumulus.ini anyway.

Well, that parameter/variable was not in the original 'cumulus.ini' file when I installed Cumulus ... but then upon reading the information about the "Cumulus.ini" on the Wiki pages, I decided to add the parameter/variable to my 'cumulus.ini' file.

I presumed the main reason why the 'VP2SleepInterval =' parameter/variable had not been included into the standard issued 'cumulus.ini' file might have been because the parameter/variable would have only been useful for Vantage Pro2 weather station...

DaveNZ · **Posted:** Sun Feb 07, 2010 9:35 am

For a while in my cumulus.ini file, I have had VP2SleepInterval=300, occasionally a gust is still missed due to the lag of transfer between the station and cumlulus...any more ideas? should I lower the sleep interval even more :shock:

steve · **Posted:** Sun Feb 07, 2010 10:09 am

Try 100 ms, perhaps. You could probably go to zero, actually. The DLL has to wait for the next LOOP packet from the station anyway, but I don't know what mechanism it uses for waiting. I'm not sure what the effect will be at start up because the DLL seems to return the first few readings very quickly.

steve · **Posted:** Sun Feb 07, 2010 10:58 am

Zero doesn't seem to cause any problems, so you're probably best using that.

Bruiser · **Posted:** Sun Feb 07, 2010 1:09 pm

I am not sure if this is really a Cumulus problem. There are occasional times in which a high wind gust recorded by my Vantage console is not shown in any of my PWS software. This includes Cumulus, VPlive and even partially Weatherlink. What I mean by partially Weatherlink, is a weather page that I have Weatherlink render will display the proper HIGH WIND Gust but its own graphs do not show this. When this occurs then 99 % of the time, VPLIVE and CUMULUS will have missed it also. In Cumulus and Weather Links case, I edit the high wind gust data manually. I am not sure why this occurs. Pretty strange....

DaveNZ · **Posted:** Mon Feb 08, 2010 3:01 am

steve wrote:

Zero doesn't seem to cause any problems, so you're probably best using that.

Will change that today, and see how it goes.

It's interesting sometimes watching the time elapsed between a windspeed update on the console and the corresponding update in Cumulus; sometimes it's quite quick (less than a second), but a couple of times I have seen a 2-3 seconds difference...

steve · **Posted:** Mon Feb 08, 2010 8:47 am

DaveNZ wrote:

It's interesting sometimes watching the time elapsed between a windspeed update on the console and the corresponding update in Cumulus; sometimes it's quite quick (less than a second), but a couple of times I have seen a 2-3 seconds difference...

Yes, Cumulus has no control over that. It relies entirely on how quickly the console responds to the Davis DLL and how quickly the DLL responds in turn to Cumulus. There is of course a delay while Cumulus updates its data etc, but you would expect that to be pretty constant each time.

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Max wind gust different in Cumulus

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