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Davis ISS Wind Dir not reported

Posted: Tue Dec 26, 2017 9:35 am
by rjuricic
Hi All,

Recently i discovered issue with reporting of Wind Direction data from Davis ISS to Meteostick. Wind speed is being reported normally and for direction i see constant North. When looking at raw data from meteostick, direction is 0. I have also checked using RFM69HW with arduino and got same conclusion.

ISS board was inspected visually and found that there was some kind of corrosion on contacts between wind connector and ISS board. Everything is cleaned and checked for moisture. There is no visible damage to any of IC or other soldered components - i suspect that small amount of moisture or few drops of water got into the ISS housing due to very heavy snow/rain events in last few weeks.
Cable was also inspected visually, and no damage is found.
What im unable to do is check wind sensor itself, since it is mounted on 10m pole and currently i cannot access it.

All other sensors are reporting as expected and according to Davis specificaitons in regards to reporting intervals.

Has anyone experienced similar issue to described one? Is there any other check which could be performed?
I see two possible solutions, either separate Wind reporting board or new Wind Sensor - both are some investment, and im not happy with them since ISS is active only for 1 year.

Re: Davis ISS Wind Dir not reported

Posted: Tue Dec 26, 2017 9:53 am
by iatros
do you have a Davis console with your ISS and can you see wind dir there?

Re: Davis ISS Wind Dir not reported

Posted: Tue Dec 26, 2017 10:26 am
by rjuricic
I dont have console, only ISS unit paired with Meteostick to receive data.

Re: Davis ISS Wind Dir not reported

Posted: Tue Dec 26, 2017 10:58 am
by iatros
ok
this screenshot is from your website.
Something strange is going on since Dec 9 and then again Dec 15 (although 360° is very close to the now fixed 5°, if you consider the position of the anemometer arm).
Can you make out whether the wind vane with the anemometer cups up the pole is changing direction from time to time?
Can you see the cups turning? Your wind speed is rather low and very constant since Dec 9 .
Martin

Re: Davis ISS Wind Dir not reported

Posted: Tue Dec 26, 2017 12:05 pm
by rjuricic
Problems started on Dec 9.
Cups and vane is freely moving, here is screenshot from interactive chart showing that speed is ok:
Image

Between 16.12. and 24.12. there were stable conditions with minimum wind, and those data are correct and expected. Occasional increased wind speed data around Dec 12th, 8th and 26th corresponds to low pressure field passing nearby and it is also expected. This wind should be S, SE or SW direction.

Direction remains unchanged, there was only once short "change" towards west as seen in screen you posted, but returend to 0/360.

Robert.

Re: Davis ISS Wind Dir not reported

Posted: Tue Dec 26, 2017 1:45 pm
by iatros
so the problem resides probably in the transmission of the vane position in the electric signal in the anemometer - up the pole....

Re: Davis ISS Wind Dir not reported

Posted: Tue Dec 26, 2017 4:46 pm
by Luc
Did you check the condition of the 'WIND' connector inside your ISS? Maybe the contacts are corroded or wet.

Re: Davis ISS Wind Dir not reported

Posted: Tue Dec 26, 2017 8:30 pm
by rjuricic
Yes i did, they were wet. I have dry cleaned them and also checked all other contacts for moisture.
Even when found that contacts were wet, wind speed was still reported, but not direction.