Negative rain?

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HeinrichH
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Negative rain?

Post by HeinrichH » Thu Jun 10, 2010 8:24 pm

Strange values for rain, all the values shown in the graphic are negative but there was only some rain yesterday and I'm sure it was positive!
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admin
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Re: Negative rain?

Post by admin » Thu Jun 10, 2010 9:43 pm

Negative rain is indeed something funny :P

I looked at your setup. You have two rain sensors in operation.
rain0 has a total counter value of 406.6mm
rain1 shows total counter value of 656.1mm

On the settings page I can see that an offset of -458.8mm is applied to sensor rain0.

Having that it is "logical" that rain0 reports bad data. Could you please check with your Meteohub,
if there is also defined that negative offset to rain0?

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HeinrichH
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Re: Negative rain?

Post by HeinrichH » Fri Aug 06, 2010 6:26 pm

Sorry for the late reply but I was not able to reply earlier, no internet in the middle of the Libyan dessert.

It's correct, I'm using 2 rain sensors, the Vantage station is my main weather station and the RFXcom receiver with Oregon Scientific stuff is used as backup.
Last year I had some problems with the Davis rain gauge so I had to correct the values stored in Meteohub, thats the -458.8mm correction value.

So rain0 should be the sensor Meteoplug should looking to and it's getting more weird, look to the Panóias Meteo station at the map, the negative value is exploding
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Re: Negative rain?

Post by admin » Sat Aug 07, 2010 12:41 pm

I looked at your actual data and I see that the calibration offset for rain0 is -458.8 mm (since 18th Nov 2009). Actual rain counter for rain0 is at 406.6 mm. It have had no increase during July and August so far. As written before, the root cause for negative rain is related to a calibration offset that does not fit to the actual rain counter value.

As you deliver data from a Meteohub system, it would be interesting if recent Meteohub counter values for rain0 do also report 406.6mm?
I am still struggling, where the difference between your Meteohub situation (where I guess rain gets reported correctly) and the Meteoplug data is.
Looking purely at the Meteoplug data, the data and calibration itself seem to be the problem, not the computation done by the Meteoplug server.

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Re: Negative rain?

Post by skyewright » Sat Aug 07, 2010 2:57 pm

admin wrote:I looked at your actual data and I see that the calibration offset for rain0 is -458.8 mm (since 18th Nov 2009). Actual rain counter for rain0 is at 406.6 mm.
If I may contribute a thought...

I think that the root cause of this is that the Davis VP2 resets its rain total to zero at the start of a new year (It may be possible to set an alternative date for the start/end of the rain season, but let's assume the change of year applies in this case).

i.e. the offset made sense to the end of 2009 but there then needs to be an additional calibration offset of 0.0mm effective from 20100101000000.
David

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HeinrichH
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Re: Negative rain?

Post by HeinrichH » Sat Aug 07, 2010 6:15 pm

David,

Thanks for the hint, I'm going to try that

Henk

I've tried that, no luck, on the moment:
Daily -1003 mm
Monthly -8917.3 mm
Annual -83129.4 mm

Last rain was 57 days ago and accumulated annual rain according Weather Display 433.4 mm

I don't know whats going on, Meteohub should only look to the same sensors I defined for the weather networks, basically the "0" sensors
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Re: Negative rain?

Post by skyewright » Sun Aug 08, 2010 4:16 pm

HeinrichH wrote: I've tried that, no luck, on the moment:
Daily -1003 mm
Monthly -8917.3 mm
Annual -83129.4 mm
Those are amazing figures.

It's almost as though you had a large negative factor rather than an offset!
David

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HeinrichH
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Re: Negative rain?

Post by HeinrichH » Sun Aug 08, 2010 5:55 pm

I don't understand, I added the 0 mm offset for the beginning of this year, link to instrument display https://www.meteoplug.com/cgi-bin/meteo ... a4bbbdb69a
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