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Author Topic: Inspeed Vortex & HB Anemometer Control Board odd behaviour when it rains?  (Read 14376 times)

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Offline David W

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  • Isle of Skye, Scotland
    • 24 Elgol
Those figures look good  :)...
And have continued in similar vein. Both the Vortex and WMR928 think the max gust for the day so far was at 1259 (15.7 mph and 10.5 mph respectively).

shame that we (you) are in a pretty slack period for winds for quite a few days... :wink:
At least I'm not trying to run a wind farm! :wink: :lol:

Knowing how the 'old' 5.5m mast can jolt when it takes a big gust, I'm wondering how the 10m will react. I think it is well guyed (4 way (N,S,E & W) guys at 3m and 6m to anchors 6m from the mast, 3 way (~SW, ~NNW & ~ESE) guys at 8m and 9.7m to anchors 9m from the mast) but the proof of the pudding, etc....
Regards
David

Offline w0mbat

  • Posts: 305
  • W Tree, East Gippsland, Victoria, Australia
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Hi Skyewright,
I'm interested that you seem to be seeing higher start up speeds on your Vortex than I do.
Mine turns in a barely perceptable breeze and I see readings down to 1.2 KM/h which is 0.75 MPH.
I'm using the new HB wind board.
Very very happy with results and Vortex and E-Vane. The combination of these instruments and the HB 1-wire board works brilliantly.
w0mbat

Offline David W

  • Posts: 2,006
  • Isle of Skye, Scotland
    • 24 Elgol
I'm interested that you seem to be seeing higher start up speeds on your Vortex than I do.
Mine turns in a barely perceptable breeze and I see readings down to 1.2 KM/h which is 0.75 MPH.
Me too. "On the bench" with a fan I'm sure I observed it starting at around 0.5 - 1mph, and literally moments ago I glanced up (it's visible from where I sit) and saw it start at a really lazy pace (very easy to count rotations), with the WMR928 stationary below it.

However, more often over the last week I've seen the WMR928 rotating slowly and the Vortex stationary, but the WMR928 seems to require at least 2-3mph to get it going? Looking at the relative behaviour of the two OS anemometers (both lower and one some 40m away in a less favourable position for the current northerlies) I almost wonder if in these very light condition they are just catching 'ground effects' caused by buildings and local slopes, effects that the better positioned vortex is free from?


Very very happy with results and Vortex and E-Vane. The combination of these instruments and the HB 1-wire board works brilliantly.
Very happy here too.  :D

I've come to the conclusion that my "gust" speeds are a bit too high at present, but that's me not the hardware; I realised there was a problem in how I was assessing time spans in the custom code (I normally program in Windows, not Linux). I've now found a better time function. I still expect/hope the Vortex will spot "better" gusts than the OS anemometers, but 50-60% seems a bit too much!  :lol:
Regards
David

Offline David W

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  • Isle of Skye, Scotland
    • 24 Elgol
...I've now found a better time function. I still expect/hope the Vortex will spot "better" gusts than the OS anemometers, but 50-60% seems a bit too much!  :lol:
With the new code then once the average is above ~4-5mph the Vortex is reporting averages slightly above the OS anemometers, and gusts of up to around 25-30% higher. This seems consistent with relative positioning and the expected 'advantage' of 3 second gust measurement over 14 second gust measurement (I recall reading a topic where someone did a empirical analysis comparing gust speeds from various time spans).

By observation the Vortex cups do start in speeds as low as ~1mph (i.e. >2 seconds per rotation!), but nonetheless it seems that when the 5 minute average is below about 4-5mph, the OS anemometers (especially the WMR200) record more wind than the Vortex. It seems possible that this is due to 'local factors', e.g. what little air movement there is having to go 'around' the house and that effect being spotted by the lower anemometers? Intruiguing, but hey, it's probably really the windier days that I'm more interested in.  :wink:

Two graphs attached, one showing the max gust in each 5 minutes for the last 24 hours for all 3 anemometers, the other showing the 5 minute averages for the same period.
Regards
David

Offline MichaelPT

  • Posts: 1,194
  • Staffordshire Nr Leek
    • Weather-Above
hi everybody



 I've setup HB Anemometer Control Board ,

 it working  data is looking  good  I've also  attached  the surge protector  I made some time ago

 this is not  affecting the data :D

mick 

http://www.weather-above.com/Anemometer%20Controller%20Board.html

Offline David W

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  • Isle of Skye, Scotland
    • 24 Elgol
Re: Inspeed Vortex & HB Anemometer Control Board odd behaviour when it rains?
« Reply #50 on: September 10, 2009, 01:48:28 PM »
After well over a month of smooth running, including the first storm of the season the day, before I had odd behaviour between 0315 and 0615 yesterday morning resulting in unwarranted gusts of up to 105mph!

During that period there were no single second reading that were "out of range", and few one second step changes that weren't "reasonable in some circumstances" and thus hard to filter logically as spikes.

Some sort of electrical interference at a frequency & duration that hadn't cropped up so obviously before seems the almost certain cause.

Taking a close look at the data the, 105 mph gust could have been spotted logically quite easily (a 50mph acceleration between one second and the next!), but just before that there was another peak well over 90mph that was much more subtle, with each step in the chain quite reasonable in itself.

The more I look at the data the more it looks as though hardware (perhaps plus a little extra spike logic) is the best angle of attack.

I'm assuming that the interference is coming in short bursts of highish frequency rather than being sustained lower frequency.

The current low pass filter clips at about 160 Hz in theory (equivalent to 400 mph if sustained, i.e. well beyond any real weather), but that assumes no extra resistance or (probably harder to guarantee?) capacitance in the circuit. Without a scope (and ideally a signal generator?) it's hard to be certain exactly what it is really clipping at and (aside from reporting invalid data) the last thing I want to have is a system that starts clipping real gusts.

So here's what I have in mind. Maybe someone with more idea of electronics than I could comment on the plan?

If the weekend is dry (as looks possible) I hope to try adjusting the filter so that the theoretical clip is within what is actually happening and see how theory compares to reality. Then I can maybe raise the limit again to a value that is tighter, but still with a safety margin for real weather.

e.g.
100K and 0.1uF in theory clips at 15.9Hz (~40mph)
200K and 0.1uF in theory clips at 8Hz (20mph)
470K and 0.1uF in theory clips at 3.4Hz (~8.5mph)

If one (or hopefully more) of those seem to give a reasonable match between theory and practice, then maybe a couple of 100K and a 4K7 in series might be a decent "as low as reasonable without getting too close to potentially real data" filter?

24K7 &  and 0.1uF in theory clips at 65.5Hz (~160mph!)

How's that sound as a plan?

PS. So what chance a flat calm at the weekend, eh?   :wink:
Regards
David

Offline David W

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  • Isle of Skye, Scotland
    • 24 Elgol
Re: Inspeed Vortex & HB Anemometer Control Board odd behaviour when it rains?
« Reply #51 on: September 11, 2009, 08:51:48 PM »
I managed a test:

470K and 0.1uF in theory clips at 3.4Hz (~8.5mph). I practice with the wind gusting to around 15mph at the time that clipped 1 second gust readings to 11mph.

The anemometer is now back in service running with a 10K resistor & 220nF capacitor, a  combination that theoretically clips at slightly less than half the original frequency, and which hopefully will be enough to avoid future problems.

There is probably scope for further reduction (the current threshold equates to a 180mph gust!) but that would involve either series or parallel resistors so probably best left for a soldered version rather than the connector block arrangement that is currently in use!
Regards
David

Offline David W

  • Posts: 2,006
  • Isle of Skye, Scotland
    • 24 Elgol
Re: Inspeed Vortex & HB Anemometer Control Board odd behaviour when it rains?
« Reply #52 on: September 20, 2009, 09:23:04 PM »
The anemometer is now back in service running with a 10K resistor & 220nF capacitor, a  combination that theoretically clips at slightly less than half the original frequency, and which hopefully will be enough to avoid future problems.
Rats!  :(

First decent winds since the change over and the current combination is clipping at around 16Hz in practice, well below the theoretical 72Hz. So, any rotation above the high 30's in mph is getting clipped. The result is apparent "1 minute" wind speeds of around 5mph during a gale!

Edit: I've just added an image to illustrate the positions of the capacitor and resistor in the circuit. I've also shown the 1 M ohm restor that Eric mentioned. I'm not at all clear how that might be affecting matters...
« Last Edit: September 21, 2009, 08:41:21 AM by skyewright »
Regards
David

Offline nellyt

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A rather old topic this but I have just experienced the same problem.
OWS with Hobby Boards ACM/control board has been working fine indoors during testing for months.
Installed it two days ago in stable weather and it has been ticking over and reporting about 5m/s winds which is about right.
Today with little to no increase in wind speed it started raining.
From as far as i can tell exactly at that point onwards it has been reporting 40-80m/s
I have looked at the raw counter values and they are indeed going up at the speed indicated.

Did David W ever resolve his problem?
Has anyone else experienced this and resolved the issue?

thanks

Offline Weather Display

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    • Weather Display
could be a ground loop problem?