Wind speed not working

[Tau Bootis]

Hi

My wind data has stopped working again; I have checked every thing I can think of, to no avail, this happened before back in August and after cleaning RJ11s and replacing the batteries it was sorted; but not this time.

This is the status at the moment; the wind direction is working through to my console but it is not being collected by Cumulus, the wind speed is not working on the console but there is random resistance activity on the RJ11 which connects to the sender unit (0.5k Ω to 36k Ω), I also plugged the rain gauge into wind socket and was able to generate some wind speed by tipping water in, so the only thing I can think of is that the resistance being generated by the anemometer is not good enough – I am not an expert in that field.

I have cleaned the RJ11 at the anemometer (which had one discoloured pin) and also I have had the sender unit apart, cleaned up the board & checked RJ11 socket connections.

As I type this the thing has just sprung into life for the first time in days; and then went dead again even though there is a constant light breeze, it does appear though that Cumulus needs data from the anemometer before the direction works, can anyone confirm this.

Does Vaseline on the connectors help or hinder the connection?

Any ideas much appreciated.

Regards

[steve]

it does appear though that Cumulus needs data from the anemometer before the direction works, can anyone confirm this.

It just reads the data that it's given. Perhaps you have 'use bearing zero when calm' set?

[Tau Bootis]

Thanks Steve, I just thought of that and disabled it a few minutes ago.

[mcrossley]

The wind speed sensor is just a magnetic reed switch that shorts out the wires to produce a pulse for every revolution (or maybe two - it doesn't matter! ). So you should see an open circuit and pulses of low resistance, if the sensor is spinning your meter will probably integrate the resistance over time, so you need to pull the sensor down and slowly rotate it to find the true resistance being seen by the transmitter.

[Tau Bootis]

OK thanks Mark
I guess I will have to get back up onto my chimney then

[mcrossley]

oh dear I keep meaning to get mine put there, but there are disadvantages.

[Tau Bootis]

Hi
All sorted; this is what I did:

I took my anemometer and direction indicator apart…OMG they were both full of damp and dead fleas; I had to clean the direction indicator in situ and by the time I’d finished it was dark and raining; during my heavy handed clean up operation I managed to break the reed switch in the anemometer they are so fragile.
I found some reed switches on Ebay; 10 for £2.95 incl. p&p that’s not bad considering I almost bought 2 for £5.97 from Maplin.

They arrived yesterday and I set about replacing the broken one, one thing I noticed was that the flat contacts within the switch were at 45° to the horizontal this is to ensure that the switch operates when the magnet passes on each side, I’m not sure whether it was supposed to have been at 90° but as it worked at 45° that was how I intended to fit the new one.

These are fiddly to solder without cracking the glass or buckling the contacts, so on my first attempt the orientation was wrong and I only achieved one contact per revolution, so I de-soldered one end and carefully twisted the switch to 45° and re-soldered it; now it switches twice per rev. Indecently you can actually hear the switch operating as the anemometer turns.

The anemometer bearing seemed to be as good as new but the wind direction bearing felt a little dry, so I gave them both a bit of 3 in 1.

My station is almost 2 years old now and judging by the state of the internals I think a 12 to 18 month service would go a long way to keeping them in good working order, just remember to be extra careful of those reed switches!
I think the reason all the fleas were dead is because I had sealed them in by blocking the RJ11 socket with Vaseline back in August when the problem first appeared. I have now tried to seal all gaps and cracks with grease to prevent the ingress of moisture and insects.
I checked the rain gauge and apart from some dirt in the buckets it was fine.