rain total difference - Printable Version

rain total difference - Printable Version

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rain total difference - danner - 29-09-2017

Just received the first rainfall with my new 8" rain gauge. Cumulus MX recorded 0.25" of rain and the Pro2+ receiver is showing 0.20".

TX1 is set for Collector_Type 0.254 for a bucket tip of 0.01".

CumulusMX multiplier is 1.27

Did I miss a setting somewhere?

TIA

RE: rain total difference - danner - 29-09-2017

With a multiplier in CumulusMX of 1.27, 0.20" of rain comes out to 0.254" or rounded to 0.25". So the question is which figure is correct? The 0.20" displayed on the Pro2+ console or the 0.254" in CumulusMX?

Unfortunately I don't have a manual rain gauge, but we received a little more rain since my first post. My Ambient Weather station currently says 0.23", the Pro2+ says 0.22", and Cumulus says 0.28".

If the Pro2+ reading is correct then the multiplier in CumulusMX should be set to 1.

RE: rain total difference - danner - 29-09-2017

I did a search over on the cumulus forum and Steve said "If you set a multiplier, Cumulus will read the rate from the station and apply the multiplier to it." So when the WeatherDuino communicates with cumulus it tells it each tip is 0.254mm and cumulus then applies a 1.27 multiplier, because that's what I have set. If that's the case then the multiplier should be 1.00 not 1.27. Do I have that right?

RE: rain total difference - JT118 - 29-09-2017

You are correct set it to "1". If your Weatherduino software is set correctly to reflect the calibration of the gauge then all other multipliers should be 1.

See here for rain gauge calibration:
http://www.meteocercal.info/forum/Thread-New-Brisbane-Australia-WeatherDuino-Station-Coming-Together?page=2

RE: rain total difference - danner - 29-09-2017

OK thanks.

RE: rain total difference - werk_ag - 29-09-2017

(29-09-2017, 11:44)JT118 Wrote: You are correct set it to "1". If your Weatherduino software is set correctly to reflect the calibration of the gauge then all other multipliers should be 1.

See here for rain gauge calibration:
http://www.meteocercal.info/forum/Thread-New-Brisbane-Australia-WeatherDuino-Station-Coming-Together?page=2

Sorry to say, but that info is not correct.

No matter the settings you did on the TX software, whenever we are using a rain gauge with a tip bucket different from 0.2mm, we should always set a multiplier on Cumulus

I already have explained the reason for this on many, many posts on the forum.

Cumulus counts number of tips, and for him each tip is always 0.2mm. Cumulus get this info at startup from the station, and our emulation always report a as metric Davis (0.2mm rain gauge). Hope this makes things clear.

Lets try to illustrate this with an example for a 0.254 rain gauge:
Cumulus gets info about one "tip" of rain:

Situation with a multiplier of 1:

1 * 0.20 *1 = 0.20mm of rain (wrong value)

1* 0.20 * 1.27 = 0.254mm of rain (right value)

RE: rain total difference - werk_ag - 29-09-2017

(29-09-2017, 11:19)danner Wrote: So when the WeatherDuino communicates with cumulus it tells it each tip is 0.254mm and cumulus then applies a 1.27 multiplier, because that's what I have set. If that's the case then the multiplier should be 1.00 not 1.27. Do I have that right?

Here is the misunderstood. WeatherDuino doesn't pass to Cumulus, the user defined value of each tip bucket. It only passes the number of tips occurred. Then, Cumulus computes the rain based on the assumption that each tip have a value of 0.2mm, that's the reason you need to set a multiplier.

I already have explaining this, so many times, that it starts to be annoying to me, mainly because it seems that my instructions don't have any credit.

I'm gonna say this for the last time: For any rain gauge, where each rain tip is different from 0.2mm, we should always set a multiplier on Cumulus according to this formula:

Multiplier = Bucket Type / 0.2

0.254 / 0.2 = 1.27

Each one will do whatever he likes, but the correct way is the one explained above.

(29-09-2017, 09:35)danner Wrote: Just received the first rainfall with my new 8" rain gauge. Cumulus MX recorded 0.25" of rain and the Pro2+ receiver is showing 0.20".

Regarding to this, I will recheck if there isn't any problem with the rain values shown in inches, on the Weatherduino display. Can you please also check if the rain units in Cumulus MX are set to inches.

RE: rain total difference - danner - 29-09-2017

(29-09-2017, 17:05)Werk_AG Wrote: I already have explaining this, so many times, that it starts to be annoying to me, mainly because it seems that my instructions don't have any credit.

Sorry, I wasn't trying to be annoying. Just trying to figure out where the discrepancy is. Your words have a lot of credit, after all I set the cumulus multiplier as per your instructions. :-)

Quote:Regarding to this, I will recheck if there isn't any problem with the rain values shown in inches, on the Weatherduino display. Can you please also check if the rain units in Cumulus MX are set to inches.

Great, that's all I was trying to figure out, whether I set something incorrectly somewhere or if it is something else that needs to be addressed.

Yes, cumulus mx is set to imperial values.

[Image: ZsHIbSQ.jpg]

RE: rain total difference - werk_ag - 30-09-2017

I'm working on this on the last 4 hours, and we may have here a great problem... I still haven't many answers, but up to now I discovered that Cumulus MX works differently than Cumulus 1, on my tests (and in my live site too) I only use Cumulus 1, this is why I had never noted this possible issue, that only happens when the user sets CumulusMX to use Inches.... If the thing is what I'm thinking, that will be very difficult to solve... Contrary to Cumulus 1 which reads the type of rain gauge (metric or imperial, in our emulation always metric) from the station eeprom, Cumulus MX seems to automaticaly assume the type of the rain gauge (metric or imperial) from the type of units selected by the user.

With Cumulus 1, everything is working fine.
Lets see if I will be able to find a universal solution for this.

RE: rain total difference - werk_ag - 30-09-2017

Regarding this matter, I posted this question on the CumulusMX forum:

Quote:Contrary to Cumulus1 which reads the type of the rain gauge (metric or imperial) from the value stored in console Eeprom, it seems that CumulusMX assumes a default value based on the units selected for rain. I'm wrong?
If I select "mm" each rain tip is multiplied by 0.2mm, but if I select "in" as unit, then each rain tip is automatically multiplied by 0.254mm.
There is any setting that we could add to Cumulus.ini to make CumulusMX count each rain tip as 0.2mm independently of the selected units?

Any possible solution will depend on the answer.