Rain Counter error in log file

[defiance50]

Hi,
I have only just started using Cumulus, but have used other software for a few years. I also just purchased a WH1080 (Maplins for 49.99) and am impressed so far (5 days).

I have noticed an issue today with 2mm of rain appearing in one minute, despite no rain falling. I am using a modified gauge as the ones that come with these stations are pretty poor. My gauge is good and working okay. I have put a correction factor into Cumulus as my gauge tips evry 0.25mm, not 0.3mm.

I have pasted a few lines from the Aug14 log file which shows the error occuring at 13:55 today.


19/08/14,13:53,17.1,60,9.3,1.5,6.0,61,0.0,0.0,1015.2,2.4,21.3,53,2.7,17.1,17.1,0,0,0.00,0.00,16.4,711,0.0,338,0.0,0.0
19/08/14,13:54,17.1,59,9.0,1.6,6.0,60,0.0,0.0,1015.0,2.4,21.3,53,2.7,17.1,17.1,0,0,0.00,0.00,16.3,710,0.0,225,0.0,0.0
19/08/14,13:55,17.0,58,8.7,1.5,6.0,90,0.0,0.0,1015.2,0.0,21.3,53,0.6,17.0,17.0,0,0,0.00,0.00,16.2,708,0.0,180,0.0,0.0
19/08/14,13:56,17.0,57,8.4,1.4,6.0,101,0.0,2.0,1015.2,2.4,21.3,53,3.3,17.0,17.0,0,0,0.00,0.00,16.1,707,0.0,135,0.0,2.0
19/08/14,13:57,17.0,57,8.4,1.4,6.0,112,0.0,2.0,1015.1,2.4,21.4,53,4.7,17.0,17.0,0,0,0.00,0.00,16.1,705,0.0,135,0.0,2.0
19/08/14,13:58,17.0,57,8.4,1.6,6.0,119,0.0,2.0,1015.1,2.4,21.4,53,3.9,17.0,17.0,0,0,0.00,0.00,16.1,704,0.0,315,0.0,2.0
19/08/14,13:59,16.9,56,8.1,1.5,6.0,134,0.0,2.0,1015.2,2.4,21.4,53,1.9,16.9,16.9,0,0,0.00,0.00,15.9,702,0.0,270,0.0,2.0
19/08/14,14:00,16.9,55,7.8,1.5,6.0,177,23.9,2.0,1015.2,2.4,21.4,53,5.2,16.9,16.9,0,0,0.00,0.00,15.8,701,0.0,315,0.0,2.0
19/08/14,14:01,16.9,57,8.3,1.6,6.0,190,0.0,2.0,1015.2,2.4,21.4,53,2.7,16.9,16.9,0,0,0.00,0.00,15.9,699,0.0,45,0.0,2.0

Data is being logged at 1minute intervals.

You will notice the rainfall counter goes from 2.4 at 13:54 to 0.0 at 13:55 and then back to 2.4 at 13:56.

The drop from 2.4 to 0.0 is ignored but the rise from 0.0 to 2.4 is not and shows up at 13:56 as 2.0 mm in daily rainfall. ( this is 2.4 mm multiplied by my correction factor for my non standard gauge).

Can anyone help with why the unit should send out an incorrect counter reading, and is there anyway that Cumulus could ignore values that are obviously wrong ( negative rain)?

Everything else is going well with the new station.

John

[steve]

Cumulus does already ignore values that are obviously wrong. There is a large amount of code in Cumulus already to try to cope with the erratic readings that Fine Offset stations are prone to produce at times. If the rain counter goes down, Cumulus retries the reading six times, and if the counter stays the same, it accepts the counter and starts again from there. If the counter subsequently goes up again, then of course this means that Cumulus will record that as rainfall.

Perhaps in future I will be able to add yet more code to cater for yet more Fine Offset oddities, but for now I'm afraid that if your station does what it apparently did, you will get the result that you got - sorry.

When you say you are using a modified rain gauge, do you mean that you have modified the gauge supplied with the station (as many people have), or you are using a completely different gauge?

[defiance50]

Steve,

thanks for getting back so quick. I understand these units are a bit prone to issues, but for £49.99, I couldn't resist.
I have already corrected as it is easy to do with Cumulus.

I already have a Nexus but I use WD to log that. It has major issues with the wireless rain gauge not always connecting, so it misses a lot of rain and the update interval on the rain is over 2 minutes.

At the moment, I am comparing the two, before making the Fine Offset my main station. The pressure sensor seems a lot more stable on this one. The Nexus does not like changes in temperature of the base unit. The great thing about the nexus is the additional temp sensors, so may keep it going for my own interest.

The gauge I am using is an old tilting syphon gauge. Someone was throwing one away so I grabbed it. It had none of the mechanism in it but the huge funnel, which hinges open, is great for testing different size buckets. I hope to set up some to give 0.1mm /tip but that depends on the kids, wife and work. The gauge that comes with the FO is pretty useless really, especially if mounted on the pole, so I just made up a new cable to fit the transmitter and terminated it on my buckets in the BIG gauge. The buckets have got two reedswitches, one to go to my old system and one to the new.

My Nexus is shrewtonweather.co.uk and the new FO is shrewtonwx.net

Thanks again

John

John

[defiance50]

PS
the tilting syphon deals with footballs a lot better. I find that the little plastic gauges get destroyed quite easily by enthusiastic young footballers but footballs just bounce off the large gauge.

I also use a rather old small Stevenson Screen to put the temperature sensors/transmitters in. Gives much better results.

John