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Author Topic: First Storm of the Season on it's way!  (Read 1990 times)
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munrobaggins
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« Reply #30 on: September 11, 2009, 10:27:55 PM »

I was wondering if you had done a trial with changed res/cap components...Only a real "blow" will tell if the theory works...here's hoping!
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Baggins
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« Reply #31 on: September 12, 2009, 01:59:28 PM »

Only a real "blow" will tell if the theory works
Yep. There is no other way of testing. I can't even use the trick (Cumulus) Steve mentioned on his forum of a ladder and a compressor!

a) I don't have a compressor.

b) I don't have a ladder that long, and neither do I fancy laybacking my way up the pole! I imagine I'd have difficulty with a VS 4c nowadays let alone an (I'm guessing) E5 5c! LOL!

here's hoping!
Indeed.

PS. Gorgeous day here today. Back out now to do a few more outdoor jobs (one of which may be a bit of concrete around the blocks that the new mast's tripod is bolted to).
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David
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« Reply #32 on: September 15, 2009, 09:48:07 PM »

I would question that one, unless you're in a glen where the wind funnels past or you're on top of Munro.  Wink
Are you having problems yourself today?

I was drawn to take a closer look by the 19.6mm of rain then and found "Today: 118.1 mph 14:38" too.  Shocked

Edit: I see the figure has come down a bit now, to "Today: 20.0 mph 21:46", a bit closer to my own 17.2 mph  Wink
« Last Edit: September 15, 2009, 10:11:02 PM by skyewright » Logged

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David
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« Reply #33 on: September 16, 2009, 12:14:32 AM »

Yep, I had one bad packet that WD seems to have made up all by itself.
It gave a gust of 103 knots and 19mm of rain, all in a minute!

Took about an hour to correct all the logs plus the daily, monthly, yearly & all-time records.  Roll Eyes
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skyewright
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« Reply #34 on: September 16, 2009, 04:03:49 PM »

Yep, I had one bad packet that WD seems to have made up all by itself.
It gave a gust of 103 knots and 19mm of rain, all in a minute!
Sad
I recall seeing the odd thread on Weather-Watch about Davis wind spikes, but I have a feeling that it's usually a specific value that gets mentioned (somewhere around 76mph?) and not so far as I recall associated with a rain spike. Hopefully yours was a one-off never to be seen again.

Took about an hour to correct all the logs plus the daily, monthly, yearly & all-time records.  Roll Eyes
BTDTGTTS...
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« Reply #35 on: September 20, 2009, 06:24:19 PM »

I was wondering if you had done a trial with changed res/cap components...Only a real "blow" will tell if the theory works...here's hoping!
It looks as though the filter is too low and is "clipping" good data...  Sad

The wind is getting up here. Both the WMR200 and WMR928 are picking up, but the Vortex gusts (i.e. max in each minute) are not picking up beyond where they've been all day and the windspeed (i.e. average over the minute) is going down markedly (implying that a lot of 'clicks' are being clipped out). See 1st attachment. It's "unknown" for the WMR918 'wind' to be greater than the Vortex except in a near flat calm.

I've just switch over to the WMR200 for the present. 2nd attachment is a WD screen - the effect of windspeed of the change over to the WMR200 at just after 1800 is pretty obvious!

From the look of the forecast it could be a few days before it's fit to open up the IP65 control box to adjust the filter settings...
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munrobaggins
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« Reply #36 on: September 20, 2009, 07:09:49 PM »

...It looks as though the filter is too low and is "clipping" good data...  Sad

... 1st attachment. It's "unknown" for the WMR918 'wind' to be greater than the Vortex except in a near flat calm.

I've just switch over to the WMR200 for the present. 2nd attachment is a WD screen - the effect of windspeed of the change over to the WMR200 at just after 1800 is pretty obvious!

Well...that is what Trials are for I guess....and you have definitely proved that the current setup is incorrect.

The graphs certainly show that the Inspeed data flow is in error somewhere..

Shame that you now have to wait for decent Wx to gain access to execute a change.

It would seem that the old fashioned direct connection via the Inspeed serial port (to USB converter in my case), to the PC and thence WD is actually very good methodology....It certainly checks out very well with my Davis anemometer..

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« Reply #37 on: September 20, 2009, 09:57:16 PM »

Well...that is what Trials are for I guess....and you have definitely proved that the current setup is incorrect.
Indeed.
After writing the earlier message I took a look at the debug data (every minute I have the code dump the "1 second" data records to a text file). In that the problem was very obvious with great swathes of zeros.
It looks as though clipping is cutting out anything above about 16Hz, so any rotation at above the mid 30's mph is getting lost.
The theoretical clip for the current combination (10K ohm & 220nF) is 72Hz.
10K ohm & 100nF give a theoretical clip of 15.9Hz, but I'm sure I didn't accidentally use a 100nF as the ones I have of those types look entirely different. There may of course be additional unknown factors in the circuit...

Quote
Shame that you now have to wait for decent Wx to gain access to execute a change.
In theory I could have a wire pair running all the way from the anemometer to the office as there is a length of 6 core alarm wire running alongside the UTP, though I'd need to open up the IP65 control box to swap those wires over anyway. The resulting wire run would be around 50m; even the 11m or so between the anemometer and the control box seemed to be of great concern to Eric V so the idea of 50m would probably give him nightmares!

Quote
It would seem that the old fashioned direct connection via the Inspeed serial port (to USB converter in my case), to the PC and thence WD is actually very good methodology....It certainly checks out very well with my Davis anemometer..
Yes, though, as we have worked out, that also uses a Low Pass filter. Hopefully it's just a matter of getting the values right; the great difficulty is in testing any particular set of values.

I wonder if the Weather Shop will be doing a Christmas special on VP2's this year. LOL!
« Last Edit: September 20, 2009, 10:01:19 PM by skyewright » Logged

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David
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« Reply #38 on: September 27, 2009, 01:39:06 AM »

Just checked my visitor figures for yesterday, normally I get an average of 140 to 160 unique visitors per day with 250 to 320 page views.
Yesterday saw 648 unique visitors and 1409 page views!!  Grin

that was me, lol way to much time on you're site :lol:
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« Reply #39 on: September 27, 2009, 12:27:27 PM »

No just you, although I did notice a hundred visits from you, but that number was from individual visitors rather than page hits as it looks at IP addresses.  Wink
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« Reply #40 on: September 27, 2009, 06:37:50 PM »

I was only jokeing  anyway lol
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