Temperature sensor failure - best method of dealing with it

[Graham64]

For the 2nd time in 2 years my Davis VP2 temperature sensor has failed - it is constantly reading -39.6oC. We are having a bad summer in Cornwall but not that bad!
I will get it fixed but meanwhile need some advice on the best way of dealing with the lack of accurate temperature & humidity readings coming into Cumulus.

Shall I:
A) Do nothing and tidy all the records etc up when the sensor is repaired.
B) Unplug the temperate/humidity at the station so that no readings are sent. Will Cumulus deal with this?
C) Switch everything off and not record rain, wind and solar until the repairs.

Any suggestions on the best way of dealing with this?

Have I been unlucky with having two sensors fail or is there a problem?

Thanks

[steve]

The VP2 temp/hum sensors don't seem to like coastal locations. I'm on my third sensor, as is the school here, and I think Dave Wheeler on Fair Isle has been through even more than that.

Unfortunately Cumulus has no notion of 'null' values, so while I think option B will work and it should cope (I think the Davis DLL will return an error so Cumulus will ignore the reading), it has to record something, so you may well get zero recorded. Which is possibly better than -39.6. One possible issue is that Cumulus looks for outside temperature readings as an indication that all is working, and doesn't update the logs or the web until it's had a temperature reading. The 1.9.3 beta has a cumulus.ini setting to turn off this check.

[steve]

And by coincidence, my temperature sensor has gone haywire for a while today, registering -67.8C for an hour. I hope this isn't a sign that this one is failing.

[Graham64]

Steve
Maybe your -67.8C is because you are so much further north than I am in Cornwall! I hope your sensor recovers - mine hasn't.

I have now implemented option B from above and removed the temp/humidty lead from the station, I also set the NoSensorCheck = 1 in Cumulus.ini Everything seems to be OK, all temperature readings are recorded as zero but everything else is working correctly, including the log & web updates (although I have disabled the WOW updates). So thanks very much.

Just a couple of points:
NoSensorCheck even though I was on build 1040, this setting was not in my Cumulus.ini and I added it. Do the updates not put in the new settings or do they just assume the default?

Value recorded
I still have Weatherlink going (although I'm not sure why) and I noticed that it recorded null values for temperature several hours before Cumulus started recording -39.6C. In the intervening period the Cumulus values look valid so I'm not sure what was going on. Do you know of any explanation?

[steve]

NoSensorCheck even though I was on build 1040, this setting was not in my Cumulus.ini and I added it. Do the updates not put in the new settings or do they just assume the default?

'ini-file only' settings have to be added to the file. If not present, the default is used.

I still have Weatherlink going (although I'm not sure why) and I noticed that it recorded null values for temperature several hours before Cumulus started recording -39.6C. In the intervening period the Cumulus values look valid so I'm not sure what was going on. Do you know of any explanation?

I'm not sure I follow that. Are you saying that you have WL and Cumulus running at the same time? That's likely to cause problems (except in certain circumstances).

[Graham64]

Sorry - I should have made it clear that I am using Virtual VP.

[steve]

The difference between WL logged data and Cumulus logged data is that WL periodically downloads the logger data and stores it, whereas Cumulus only ever downloads logger data at startup and then logs snapshots of 'live' data. Cumulus might have been getting occasional valid readings, which it would keep using if it subsequently got errors. So I suppose that might be an explanation.

[steve]

Mine's gone to -68.7C again this morning. Ho hum, time for yet another replacement. This one has lasted about 18 months.

[steve]

Having disconnected the sensor and reset everything, the temperature reading has gone back to -68.7C, so I guess the problem is the ISS.

Maybe it's time to give up with this weather station lark, it's getting too expensive...

[apenwith]

Hi
Oddly enough my Fine Offset temperature sensor failed last week - maybe they're all susceptible to salty air.

Regards
Alan

[iceberg]

Hi
Oddly enough my Fine Offset temperature sensor failed last week - maybe they're all susceptible to salty air.

Regards
Alan

Rainwise weather products i think is the wise choice for your salty air enviroment. Its just made for that kind of salty enviroment.

http://www.rainwise.com/

[steve]

Rainwise weather products i think is the wise choice for your salty air enviroment. Its just made for that kind of salty enviroment.

http://www.rainwise.com/

Those do look "the business". But if I got one of those I'd have to add support for them to Cumulus

[iceberg]

Rainwise weather products i think is the wise choice for your salty air enviroment. Its just made for that kind of salty enviroment.

http://www.rainwise.com/

Those do look "the business". But if I got one of those I'd have to add support for them to Cumulus

Well let me know if ever you will support it. Ill buy one.

[gemini06720]

Rainwise weather products i think is the wise choice for your salty air enviroment. Its just made for that kind of salty enviroment.

Just curious...

Both Davis Instruments and RainWise have their companies located near sea water - although on opposite coasts.

I looked at the RainWise pages and could not find anything specific about 'salty' environments - could you point me to the link and/or document where you read such information.

[iceberg]

Rainwise weather products i think is the wise choice for your salty air enviroment. Its just made for that kind of salty enviroment.

Just curious...

Both Davis Instruments and RainWise have their companies located near sea water - although on opposite coasts.

I looked at the RainWise pages and could not find anything specific about 'salty' environments - could you point me to the link and/or document where you read such information.

United Kingdom
Name Geopacks ( Education Specialists )
URL NA
Phone [44] 1837 811 020
Fax [44] 1837 810 831
Address 92-104 Carnwath Road
London, England SW6 3HW
United Kingdom

Name Meteorologica Ltd
URL www.meteorologica.co.uk
Phone [44] 7010 706946
Fax [44] 7010 708829
Address 70 Grayrigg Drive
Morecambe
Lancs
LA4 4UL
England

These 2 companies in the UK sell rain wise products.

NOAA has many rain wise weather stations up and down the east coast and have no problems at all.

RainWise is also proud to have the National Oceanic and Atmospheric Administration among our many clients.