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Author Topic: Inspeed Vortex & HB Anemometer Control Board odd behaviour when it rains?  (Read 18796 times)

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Offline David W

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I see the HB board will count up to 2kHz. At 2.5 mph/Hz (inspeed spec) that would be 5000 mph so the input can stand some filtering for this application  :lol:
Last night just at the start of a 'rain event' in flat calm conditions I spotted a reading of 0.0mph gust and 5.4mph wind. Because I wrote the code that reads the data I can tell that that means there must have been a leap in count of just under 130 in the fraction of a second between 2 sections of code.

Anything above 60m/s => ~134mph => ~54Hz average on 3 second gust measurements gets reported as "out of range" at the Meteohub stage (I only show Meteohub the highest 3 second gust in each minute) . Similarly error checking on 'wind' (which I measure over 60 seconds) regards anything over 50m/s => ~112mph => ~45Hz average  as "out of range".

The Meteohub error log does report some out of range values, but not vastly out of range (I've not noticed anything above an equivalent to around 60Hz average).

That is very limited and somewhat circumstantial evidence, but I think it does tend to suggest that the extra counts are arriving as discrete and (relatively) high frequency bursts. If my understanding is correct I think that supports your idea of using a ferrite to help filter out the bursts.
Regards
David

Offline niko

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If you try ferrite I would put it at the electronics (non-anemometer) end, then it would help to block anything picked up on the wire, I would try a capacitor across the line too. Looking at the pic in the HB manual it looks like the inputs have series resistors but (unless they are on the other side of the board) no capacitors.

How long is the cable?

Another thought just occurred to me. Do you have any overhead power lines close by? Dirty insulators will cause discharges when wet.

Offline David W

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If you try ferrite I would put it at the electronics (non-anemometer) end, then it would help to block anything picked up on the wire
I'm glad you said that. The wire at the top end has a pretty stiff outer layer. At the electronics end the wire is much more flexible.

I would try a capacitor across the line too. Looking at the pic in the HB manual it looks like the inputs have series resistors but (unless they are on the other side of the board) no capacitors.
I don't recall there being anything on the reverse side of the board, certainly nothing looking like the usual "can" style capacitor.
What sort of size?
IIRC when munrobaggings had a look inside the plug on his "Vortex with serial plug" he found a "K5U 105M EC1" which I think translates to "1uF +/- 20%"?

How long is the cable?
~35' anemometer to control board.

Another thought just occurred to me. Do you have any overhead power lines close by? Dirty insulators will cause discharges when wet.
The closest domestic supply overhead line is maybe 40m (130') away? The next higher grade line (with a "step down" to our line) ends around 50/60m away.



Regards
David

Offline niko

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Yes, that's a 1 microfarad. Theoretically a 1K series resistor and a 1 microfarad cap would make a cut off at 160 Hz (calculator here) so I think that's in the ball park, could even be a bigger cap, but without knowing exactly what the input circuit is it's a bit of a crapshoot. Either way hanging 35 feet of wire off the input without some filtering or other tricks is asking for trouble IMHO. Probably be better if the board was up the pole and the connection back was 1-wire but that would open a whole other can of worms.

Offline David W

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Yes, that's a 1 microfarad. Theoretically a 1K series resistor and a 1 microfarad cap would make a cut off at 160 Hz
Thank you. I'll try something like that once I get a hold of a suitable capacitor.
In the meantime I've already fitted the ferrite ring.
It would be interesting to see if that had an effect on its own, but from the forecast it may be several days till we see rain again. Maybe I'll have the grounding in place too by then.

Either way hanging 35 feet of wire off the input without some filtering or other tricks is asking for trouble IMHO.
Maybe, but as the Vortex comes with 25' as standard and can be ordered with up to 200' I'll probably not be the only one to try it (though the fibreglass mast may be an unusual ingredient).

When I first completed the cable run from mast to computer, but before I fitted the ACB into the box at the base of the mast to house the 1-wire ACB board I tried a couple of experiments with a simple connection using the full length from masthead to computer. Connecting the vortex and eVane direct to the ACB with the full 160' of wire was fine for the eVane, but the anemometer count was around 20 times too high presumably just down to various electrical noise (no rain in sight). However if I switched the anemometer pair over to the humble 'bicycle computer' that came with my Vortex, that managed just fine; maybe the 'bicycle computer' has some filtering built in?

Probably be better if the board was up the pole and the connection back was 1-wire but that would open a whole other can of worms.
Eric wondered about that option too, but I want to avoid it if at all possible.
I do hope to be adding a few other 1-wire things to the mast that will include mounting circuit boards (e.g. HB lightning counter, and some sort of sunshine measuring device), but I expect those to be reachable from the base (at most with the aid of a short ladder), not anywhere near the top of the mast.

Hopefully the various grounding and filtering techniques will sort it out. Time will tell...
Regards
David

Offline David W

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In the meantime I've already fitted the ferrite ring.
It would be interesting to see if that had an effect on its own, but from the forecast it may be several days till we see rain again
The "10% chance rain" came our way. The ferrite ring will need help, though it may have had some effect as there weren't any actual "out of range" errors (>60 m/s) though there were plenty of "gusts" over 50m/s.

I've had a look around in the loft. For grounding my choice may be between 1.5 mm2 (~15 gauge?) all in one length and 2.5 mm2 (~13 gauge) as two length with a join halfway. As it's all a bit arbitrary I suspect that a continuous length may have preference over 2 thicker lengths with a join? Does that seem reasonable?
Regards
David

Offline niko

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In order of preference, no join, good join, , , , , , , bad join.

Offline David W

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Conundrum...

I'm halfway through the job. The grounding wire is attached at the top end and strapped to the pole most of the way down. Then I stopped for some lunch. I couldn't resist taking a look at the figures. Even though it's dry and calm the graph the vortex was reporting winds of over 100mph (when it wasn't 'out of range'). Ah. I thought, that will be because I've attached the grounding wire at the top, but not bonded it to the earth rod at the bottom, so I've just created an even bigger antenna.

So, I nipped out and attached the grounding wire to the earth rod. Came back, checked the speed. 0 mph.  :D. But it seems that the 0mph was just chance. The next reading, and quite a few since have been back to way way too high or 'out of range'.  :(  It seems to go in 'fits and starts'.

Code: [Select]
20090711122542 wind8 129 0 0 0192
20090711122642 wind8 139 0 0 0189
20090711122743 wind8 140 0 0 0191
20090711122842 wind8 100 586 330 0159
20090711123142 wind8 118 577 293 0165
20090711123342 wind8 144 581 489 0167
20090711123442 wind8 93 581 219 0164
20090711123542 wind8 121 577 313 0162
20090711123642 wind8 125 577 241 0162
20090711123742 wind8 144 0 33 0192
20090711123842 wind8 144 577 101 0164
20090711123942 wind8 119 0 0 0193
20090711124042 wind8 119 0 0 0193
20090711124142 wind8 118 586 444 0165

So do I

i) Leave the grounding wire on, on the basis that it is "A Good Thing", raise the pole and accept that I'll have nonesense at least till I get to try fitting a low pass filter.

or

ii) Remove the grounding wire as an idea that didn't work and at least have reasonable data while it's not raining (till I get a chance to try out fitting a low pass filter).

Hmmm! At the moment I'm tending towards  i)

I'm a little interested in what would be the case if I had the grounding wire up the pole, but NOT attached to the anemometer. Unfortunately it's so well attached at the top that removing it temporarily is not practical (I'd almost be starting again from when I lowered the mast).

Another thought is that the grounding wire runs along side the anemometer/reed switch wire, but there is not a lot I can do about that.

Decisions, decisions!

Oh well off out not to do a bit more of something...
Regards
David

Offline niko

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i)

Offline David W

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i)
That makes us unanimous.  :D

I've just finished replacing the connection between the Inspeed leads and the extension. Previously a connector block in a small IP55 box strapped to the pole with cable ties. Now with soldered joins, protected by heat shrink and liquid electrical tape. I just popped in to check all is okay at the computer end. Off back out now to complete strapping the grounding wire to the mast, then time to raise it again.

w0mbat: I was um-ming and ah-hing a bit about whether or not to beef up the e-Vane. It seems pretty stout, but I can see what you mean about the possibility for vibration and I ended up going your way, attaching a 'strut' made of 12mm aluminium angle. A piccy may follow later...
Regards
David

Offline munrobaggins

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This is all getting very interesting...Your 1st precipitation test is closing rapidly!!!!!...lets hope all the theories are correct.. :)

Offline David W

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This is all getting very interesting...Your 1st precipitation test is closing rapidly!!!!!...lets hope all the theories are correct.. :)
Mast now up, and the Postie has just arrived with a parcel from Maplin.  :D
Hmmm. Do I have time to try creating a quick Low Pass Filter...

The anemometer wire connects to "+5V" and a "Counter" connections on the Anemometer Controler Board (ACB).

I know the capacitor goes across, and the resistor goes in series, but I'm not sure which 'leg' is the better home for the resistor, and which (R or C) should be closer to the ACB?

My guess is R on the +5 leg and the C closer to the ACB, but that really is a guess!

Off now to furtle in the parcel to see if I can work out which cap is which (it's a mixed bag).
Regards
David

Offline David W

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My guess is R on the +5 leg and the C closer to the ACB, but that really is a guess!
Having taken another look at the circuit, I opted for R on the "counter" leg and the C closer to the ACB. I finished wiring that up just over 5 minutes ago, and...

Code: [Select]
20090711171242 wind8 43 558 452 0172
20090711171342 wind8 39 489 442 0174
20090711171442 wind8 30 469 443 0176
20090711171642 wind8 13 586 60 0173
20090711171742 wind8 65 212 18 0185
20090711171842 wind8 34 298 35 0181
20090711171942 wind8 53 484 111 0174
20090711172042 wind8 35 577 157 0173
20090711172143 wind8 42 394 8 0178
20090711172242 wind8 42 16 5 0199
20090711172343 wind8 28 63 9 0199
20090711172442 wind8 48 11 2 0200
20090711172542 wind8 72 14 1 0200
20090711172643 wind8 87 3 0 0198
20090711172742 wind8 59 18 2 0198
(]ISO date time] [sensorId] [direction] [gust x 10] [averag x 10]  [windchill].

So there appears to be a very definite effect.  :D

Unfortunately, with the present combination too much of an effect (expected wind ~8mph, gust ~15mph, vortex => wind < 1mph, gust ~3mph).  :(

Maybe the R should have gone on the other leg?

The current arrangement is very crude, little more than the components plus connector blocks. Sort of electronics meets civil engineering!

Rather than mess further, I'll leave this combination (R = 1K ohm, C = 1uF, if I've read the R correctly ) and see how it responds when the rain arrives.

Back out now to batten down the control box for the expected rain...
Regards
David

Offline David W

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Unfortunately, with the present combination too much of an effect (expected wind ~8mph, gust ~15mph, vortex => wind < 1mph, gust ~3mph).  :(
The wind is steady and stronger now, and I'm just geting zeros (presumably nothing low enough to pass the filter).

Rather than mess further, I'll leave this combination (R = 1K ohm, C = 1uF, if I've read the R correctly ) and see how it responds when the rain arrives.
<fx: thinks> I wonder if I'm a factor of 100 out somewhere and I'm actually filtering at 1.6Hz, i.e. 4mph!  :lol: :lol:
Capacitor reads 1uF
Resistor Brown Black Red, which I think means 10 x 100 => 1000 ohm?

Regards
David

Offline niko

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Cap from counter input to ground (on the board)
Res from the counter input to the wire going to the anemometer.

Brown Black Red = 1K.

Do you have a smaller cap?

 

cumulus