Author Topic: WiFiLogger - Connect your Davis console directly to the Internet via WiFi  (Read 109325 times)

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Offline galfert

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Re: WiFiLogger - Connect your Davis console directly to the Internet via WiFi
« Reply #850 on: February 07, 2019, 04:59:01 PM »
WheatonRon,
I understand all that you said and I knew that to be a solution. But some people may not want to see Altimeter on their console and they may not want Altimeter being reported to all their online services. Some people like me want to see Sea Level Pressure on the console and they want to have Sea Level Pressure reported to all online services *except* CWOP. The Meteobridge handles this exactly how I've described where only CWOP gets Altimeter reported and everything else gets/displays Sea Level Pressure including the Console. Even though the VP2 does not have a way to handle Altimeter does not matter, because the VP2 console has LOOP2 and through that it sends Station Pressure which can then be used to properly calculate Altimeter by the weather software in your logger in the case of the WiFi Logger or the Meteobridge as I've stated or if you use a USB/IP logger then LOOP2 can be feed to your computer weather software for it to then calculate Altimeter.
« Last Edit: February 07, 2019, 05:03:30 PM by galfert »
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Offline CW2274

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Re: WiFiLogger - Connect your Davis console directly to the Internet via WiFi
« Reply #851 on: February 07, 2019, 05:17:28 PM »
Question: Does the WiFi Logger send Altimeter Pressure to CWOP?

I suspect but I'm not sure that the WiFi Logger is sending Sea Level Pressure to CWOP instead of sending Altimeter Pressure. CWOP requests that stations send Altimeter Pressure. Altimeter Pressure is something that other weather software is able to send to CWOP by using LOOP2 where the Davis console provides Absolute Pressure (Station Pressure) to then be used to compute Altimeter Pressure by the weather software (the WiFi Logger in this case). Not sending Altimeter to CWOP is a pretty big deal and it throws off quality reporting analysis of not just your station but of your neighbors which won't be happy with you if you continue to send Sea Level Pressure.

This came to my attention in this thread:
https://www.wxforum.net/index.php?topic=35756.msg370181#msg370181

most of us have set our elevation on the console to zero then calibrated our Davis consoles to match a nearby airport that reports altimeter.
Exactly. If I may add further for those who'd like to try this option, set your VP2 console when the weather is benign and the altimeter is "around" 29.92", which is standard barometric pressure.

Offline CW2274

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Re: WiFiLogger - Connect your Davis console directly to the Internet via WiFi
« Reply #852 on: February 07, 2019, 05:23:52 PM »
If the wifi logger is like the standard, which I'm betting it is, it has nothing to do but report what the console sends it, it manipulates nothing.

Offline WiFiLogger

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Re: WiFiLogger - Connect your Davis console directly to the Internet via WiFi
« Reply #853 on: February 07, 2019, 05:24:06 PM »
I have just checked.
WiFiLogger to all services is sending barometer from console.

Offline CW2274

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Re: WiFiLogger - Connect your Davis console directly to the Internet via WiFi
« Reply #854 on: February 07, 2019, 05:27:04 PM »
I have just checked.
WiFiLogger to all services is sending barometer from console.
Too ambiguous. I assume you mean whatever the console is displaying, right?

Offline galfert

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Re: WiFiLogger - Connect your Davis console directly to the Internet via WiFi
« Reply #855 on: February 07, 2019, 05:27:08 PM »
I have just checked.
WiFiLogger to all services is sending barometer from console.

Thank you. That confirms my suspicion.

Fix Request:
So now can we request the the WiFi Logger use LOOP2 to pull Absolute Pressure and then calculate Altimeter and then report Altimeter to CWOP like other weather software?
Ecowitt GW1000 | Meteobridge on Raspberry Pi
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Offline WiFiLogger

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Re: WiFiLogger - Connect your Davis console directly to the Internet via WiFi
« Reply #856 on: February 07, 2019, 05:29:42 PM »
I have just checked.
WiFiLogger to all services is sending barometer from console.

Thank you. That confirms my suspicion.

Fix Request:
So now can we request the the WiFi Logger use LOOP2 to pull Absolute Pressure and then calculate Altimeter and then report Altimeter to CWOP like other weather software?

Yes. No problem I will fix this ASAP.
Do you have direct link to CWOP instruction? I have just been looking for it, but with no luck.

Offline WiFiLogger

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Re: WiFiLogger - Connect your Davis console directly to the Internet via WiFi
« Reply #857 on: February 07, 2019, 05:32:21 PM »
I have just checked.
WiFiLogger to all services is sending barometer from console.
Too ambiguous. I assume you mean whatever the console is displaying, right?
It is sending same value which is displayed on console screen.
It is recalculated value with offset and elevation.

Offline galfert

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Re: WiFiLogger - Connect your Davis console directly to the Internet via WiFi
« Reply #858 on: February 07, 2019, 05:34:46 PM »
I have just checked.
WiFiLogger to all services is sending barometer from console.

Thank you. That confirms my suspicion.

Fix Request:
So now can we request the the WiFi Logger use LOOP2 to pull Absolute Pressure and then calculate Altimeter and then report Altimeter to CWOP like other weather software?

Yes. No problem I will fix this ASAP.
Do you have direct link to CWOP instruction? I have just been looking for it, but with no luck.

Certainly. Here is the Davis formula for doing Altimeter for CWOP. Look starting Page 10.
https://www.davisinstruments.com/product_documents/weather/app_notes/AN_28-derived-weather-variables.pdf

Quote
Altimeter Formula, A:
A = (P^N + K*Z)^(1/N), where P is the raw station pressure (in. Hg), N = 0.1903, K = 1.313E -5,
Z is elevation (feet).

REFERENCE
"Smithsonian Meteorological Tables". Smithsonian Institution Press, Washington, DC, 4th Ed.
1968.
« Last Edit: February 07, 2019, 05:40:43 PM by galfert »
Ecowitt GW1000 | Meteobridge on Raspberry Pi
WU: KFLWINTE111  |  PWSweather: KFLWINTE111
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Offline CW2274

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Re: WiFiLogger - Connect your Davis console directly to the Internet via WiFi
« Reply #859 on: February 07, 2019, 05:35:54 PM »
I have just checked.
WiFiLogger to all services is sending barometer from console.

Thank you. That confirms my suspicion.

Fix Request:
So now can we request the the WiFi Logger use LOOP2 to pull Absolute Pressure and then calculate Altimeter and then report Altimeter to CWOP like other weather software?

Yes. No problem I will fix this ASAP.

So, if I understand you correctly, you can program your logger to do what the Vue console already does? If so, you'd probably make a lot of happy VP2 user that want an accurate altimeter setting that don't want a Vue.

Offline WheatonRon

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Re: WiFiLogger - Connect your Davis console directly to the Internet via WiFi
« Reply #860 on: February 07, 2019, 05:48:07 PM »
All very interesting but the airplanes of the world and our local TV stations report altimeter why do you want to see barometric pressure differently?
Davis VP2 with SHT31 (3 complete VP2 systems—2 with a daytime fan and 1 that has a 24 hour fan); CWOP--CW5020, FW3075 and FW4350; WU--KILWHEAT17, KILWHEAT36 and KILWHEAT39; WeatherCloud.net; CoCoRaHS--IL-DP-132; and Weatherlink 2.0

Offline WiFiLogger

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Re: WiFiLogger - Connect your Davis console directly to the Internet via WiFi
« Reply #861 on: February 07, 2019, 06:13:02 PM »
So, if I understand you correctly, you can program your logger to do what the Vue console already does? If so, you'd probably make a lot of happy VP2 user that want an accurate altimeter setting that don't want a Vue.
I will make function to calculate altimeter pressure and send this data to CWOP.
Vue has option to set between barometric/altimeter, but I will take raw sensor readings and calculate altimeter for Vue and VP2.

Other services required barometric pressure.


Offline galfert

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Re: WiFiLogger - Connect your Davis console directly to the Internet via WiFi
« Reply #862 on: February 07, 2019, 06:14:27 PM »
All very interesting but the airplanes of the world and our local TV stations report altimeter why do you want to see barometric pressure differently?

First I'd like to say that I do report Altimeter to CWOP because that is how that system was designed and that is what they request. So I use both Altimeter and Sea Level Pressure depending on the service.

So to answer your question as to why I want to see barometric pressure differently [depending on service] ....Because of a few reasons:
- All the Metars around me all ASOS report both Altimeter and Sea Level Pressure. So I have no problem with either pressure.
- My weather station like the VP2 console was designed to take station pressure and calculate Sea Level Pressure. Altimeter is a different formula so I want to use my equipment the way it was designed...to show Sea Level Pressure. Doing otherwise is a hack solution and does not provide good consistent good results especially when temperature is far from 59F and/or if you are at high elevation.
- I'm a science minded person and I don't care what the dumb TV and Radio fake news media report. I don't need to compare myself to them....but I can if I want to because all I have to do is check my CWOP station data.
- I'm a science minded person and I understand the premise as to why the best way to compare two stations is to use sea level pressure because it takes temperature into account where Altimeter throws that away.
- I know and understand why airplanes need Altimeter. Because a pilot can calibrate their Altimeter when they are away from the airport that they are approaching because they aren't there yet and the temperature could be different at their location which is why Altimeter pressure was invented. It enables them to land and not crash because their altimeter is calibrated to that airport. It works for airplanes ...it is not intended for weather stations when they need to compare weather conditions.
- Since I respect CWOP in requesting Altimeter, I also respect and send Sea Level Pressure to all other online services because that is what they request.
- The majority of people on WU stations report Sea Level Pressure (because they know nothing else) so I want to be able to compare my WU with theirs. Many people have no idea what Altimeter is. And contrary to what many think Sea Level Pressure is easily gotten from your local Metar (at least for a lot of people, and I understand that not all Metars do as some are just Altimeter).
- And lastly because I feel I have a really good grip on this topic and I feel I know more than those that preach Altimeter for everything.
« Last Edit: February 07, 2019, 10:02:24 PM by galfert »
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Offline CW2274

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Re: WiFiLogger - Connect your Davis console directly to the Internet via WiFi
« Reply #863 on: February 07, 2019, 06:28:41 PM »
So, if I understand you correctly, you can program your logger to do what the Vue console already does? If so, you'd probably make a lot of happy VP2 user that want an accurate altimeter setting that don't want a Vue.
I will make function to calculate altimeter pressure and send this data to CWOP.
=D> Now, can you make our ISS's take i2c protocol......? :grin:

Offline WiFiLogger

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Re: WiFiLogger - Connect your Davis console directly to the Internet via WiFi
« Reply #864 on: February 07, 2019, 06:43:39 PM »
So, if I understand you correctly, you can program your logger to do what the Vue console already does? If so, you'd probably make a lot of happy VP2 user that want an accurate altimeter setting that don't want a Vue.
I will make function to calculate altimeter pressure and send this data to CWOP.
=D> Now, can you make our ISS's take i2c protocol......? :grin:
This CWOP pressure is my mistake. I didn't know that CWOP needs altimeter. It should be done on the beggining.

For ISS I had idea to make adapter which will be seen for ISS as SHT11, but on the other end of adapter could be any other I2C sensor.
I have checked some things. Now I don't think that will work.
Adapter should be always on. ISS is switching power on for sht11 every 3s (I think) for a short time. In this situation adapter MCU should be always on and waiting with current data for ISS.
In this case adapter should have own power = to complicated(device).

Probably better choice is to make custom firmware for ISS, but it is too much work and too big risk.

Offline WheatonRon

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Re: WiFiLogger - Connect your Davis console directly to the Internet via WiFi
« Reply #865 on: February 07, 2019, 08:23:51 PM »
Great points in post 863 galfert, and thanks for elaborating on the subject (altimeter vs. sea level pressure) for us lay weather enthusiasts like me. For those of us not at altitude my guess the differences would not be great. That said, last week it was -24F one night so the differences may have been pronounced. However, my favorite place to view my station data is MesoWest at the University of Utah. They get their data directly from CWOP. They post three pressures—altimeter, sea level pressure and pressure. Apparently, they convert altimeter they receive from CWOP and calculate the other two measurements. But at the end of the day, if NOAA that oversees CWOP believes altimeter is the right way to view weather pressure, how does a lay person argue otherwise unless you believe NOAA is not objective or has a particular bias in mind. Maybe someone can also explain what “pressure” means as listed on MesoWest vs. altimeter vs. sea level pressure.
« Last Edit: February 07, 2019, 09:22:31 PM by WheatonRon »
Davis VP2 with SHT31 (3 complete VP2 systems—2 with a daytime fan and 1 that has a 24 hour fan); CWOP--CW5020, FW3075 and FW4350; WU--KILWHEAT17, KILWHEAT36 and KILWHEAT39; WeatherCloud.net; CoCoRaHS--IL-DP-132; and Weatherlink 2.0

Offline CW2274

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Re: WiFiLogger - Connect your Davis console directly to the Internet via WiFi
« Reply #866 on: February 07, 2019, 08:57:35 PM »
Maybe someone can also explain what “pressure” means as listed on MesoWest vs. altimeter vs. sea level pressure.
Pressure is "station pressure", which has no correction factor. If you take your "pressure" and add your altitude MSL, you'll get in the ballpark of your SLP or altimeter, not sure which it more eludes to, probably SLP. For instance, if your station pressure is 29.00" and your altitude is 700' MSL, add .70" (that equates to 700' of elevation) your SLP should be around 29.70".

Offline galfert

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Re: WiFiLogger - Connect your Davis console directly to the Internet via WiFi
« Reply #867 on: February 07, 2019, 09:30:04 PM »
But at the end of the day, if NOAA that oversees CWOP believes altimeter is the right way to view weather pressure, how does a lay person argue otherwise unless you believe NOAA is not objective or has a particular bias in mind.

I don't believe NOAA started off overseeing CWOP at its inception. Regardless the CWOP system is old. It was designed before the fancy weather consoles and software that we use today I believe. Even if back then the technology existed to properly calculate Sea Level Pressure, the idea was that they wanted CWOP to be something that was easily available for the weather station enthusiasts to use and for many with a lot of equipment back then it was not possible to easily calculate and submit Sea Level Pressure, or perhaps it required prohibitively more expensive hardware. So the decision was made early on to use Altimeter because it is simpler to deal with (meaning easier to calculate) and we are now stuck with it. So it came about as a necessity and limitation of the times. Want proof? No problem read the CWOP Guide:

https://weather.gladstonefamily.net/CWOP_Guide.pdf
Quote
Note:    Altimeter  is  the  CWOP  pressure  standard  because  it  is  the  simplest  pressure reduction  format  that  most  CWOP  members  can  reliably  deliver  and  which  can  be  useful by  the  National  Meteorological  Services.

So using Altimeter wasn't the best choice for meteorology back then and they knew it. But it was the best option to create a weather network that would allow everyone to submit data easily and adhear to a standard. Because apparently back then delivering Sea Level Pressure was out of the capability of most.
« Last Edit: February 07, 2019, 09:45:52 PM by galfert »
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WU: KFLWINTE111  |  PWSweather: KFLWINTE111
CWOP: FW3708  |  AWEKAS: 14814
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Offline WheatonRon

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Re: WiFiLogger - Connect your Davis console directly to the Internet via WiFi
« Reply #868 on: February 07, 2019, 10:21:02 PM »
But at the end of the day, if NOAA that oversees CWOP believes altimeter is the right way to view weather pressure, how does a lay person argue otherwise unless you believe NOAA is not objective or has a particular bias in mind.

I don't believe NOAA started off overseeing CWOP at its inception. Regardless the CWOP system is old. It was designed before the fancy weather consoles and software that we use today I believe. Even if back then the technology existed to properly calculate Sea Level Pressure, the idea was that they wanted CWOP to be something that was easily available for the weather station enthusiasts to use and for many with a lot of equipment back then it was not possible to easily calculate and submit Sea Level Pressure, or perhaps it required prohibitively more expensive hardware. So the decision was made early on to use Altimeter because it is simpler to deal with (meaning easier to calculate) and we are now stuck with it. So it came about as a necessity and limitation of the times. Want proof? No problem read the CWOP Guide:

https://weather.gladstonefamily.net/CWOP_Guide.pdf
Quote
Note:    Altimeter  is  the  CWOP  pressure  standard  because  it  is  the  simplest  pressure reduction  format  that  most  CWOP  members  can  reliably  deliver  and  which  can  be  useful by  the  National  Meteorological  Services.

So using Altimeter wasn't the best choice for meteorology back then and they knew it. But it was the best option to create a weather network that would allow everyone to submit data easily and adhear to a standard. Because apparently back then delivering Sea Level Pressure was out of the capability of most.

 Makes perfect sense. Doesn’t Weather Underground also want altimeter?
Davis VP2 with SHT31 (3 complete VP2 systems—2 with a daytime fan and 1 that has a 24 hour fan); CWOP--CW5020, FW3075 and FW4350; WU--KILWHEAT17, KILWHEAT36 and KILWHEAT39; WeatherCloud.net; CoCoRaHS--IL-DP-132; and Weatherlink 2.0

Offline galfert

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Re: WiFiLogger - Connect your Davis console directly to the Internet via WiFi
« Reply #869 on: February 07, 2019, 11:00:05 PM »
Makes perfect sense. Doesn’t Weather Underground also want altimeter?

Nope. Weather Underground wants Sea Level Pressure. You can see it defined in their API documentation.
https://goo.gl/ZUoqvC
Ecowitt GW1000 | Meteobridge on Raspberry Pi
WU: KFLWINTE111  |  PWSweather: KFLWINTE111
CWOP: FW3708  |  AWEKAS: 14814
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Offline WheatonRon

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Re: WiFiLogger - Connect your Davis console directly to the Internet via WiFi
« Reply #870 on: February 07, 2019, 11:25:13 PM »
Makes perfect sense. Doesn’t Weather Underground also want altimeter?

Nope. Weather Underground wants Sea Level Pressure. You can see it defined in their API documentation.
https://goo.gl/ZUoqvC

What we have here is apples, oranges and pears. The feeds received by CWOP, WU, PWS, etc. are or could be all different. Fortunately, pressure may be the least important measure to many but it shows the problems when pressure is defined in more than 1 way.
Davis VP2 with SHT31 (3 complete VP2 systems—2 with a daytime fan and 1 that has a 24 hour fan); CWOP--CW5020, FW3075 and FW4350; WU--KILWHEAT17, KILWHEAT36 and KILWHEAT39; WeatherCloud.net; CoCoRaHS--IL-DP-132; and Weatherlink 2.0

Offline galfert

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Re: WiFiLogger - Connect your Davis console directly to the Internet via WiFi
« Reply #871 on: February 07, 2019, 11:42:49 PM »
Makes perfect sense. Doesn’t Weather Underground also want altimeter?

Nope. Weather Underground wants Sea Level Pressure. You can see it defined in their API documentation.
https://goo.gl/ZUoqvC

What we have here is apples, oranges and pears. The feeds received by CWOP, WU, PWS, etc. are or could be all different. Fortunately, pressure may be the least important measure to many but it shows the problems when pressure is defined in more than 1 way.

I don't see a problem. I compare my CWOP to other CWOP and nearby METAR's Altimeter numbers. And I can use my CWOP to compare with news media (which is really only repeating the local airport Altimeter). To my knowledge it is only CWOP that requires Altimeter. Every other weather online service requests Sea Level Pressure. I don't find it confusing at all. Many weather stations report to more than one service. So there is no need to compare a CWOP with a WU station...chances are that the CWOP station is also on WU so you can then compare WU to WU and if they set their console and software up properly then each of their station IDs in each respective service should get ALT (for CWOP) or SLP (for all others) just as I'm doing.

This isn't even complicated to set up. Just set your console up to SLP and have the right elevation and then let the CWOP software upload do its thing. If you have a Vue console you can continue to see Altimeter if you want but SLP would be passed to all other services that are not CWOP.
« Last Edit: February 08, 2019, 12:27:54 AM by galfert »
Ecowitt GW1000 | Meteobridge on Raspberry Pi
WU: KFLWINTE111  |  PWSweather: KFLWINTE111
CWOP: FW3708  |  AWEKAS: 14814
Windy: pws-f075acbe
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Offline WiFiLogger

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Re: WiFiLogger - Connect your Davis console directly to the Internet via WiFi
« Reply #872 on: February 08, 2019, 05:27:43 AM »
In Davis manual we have:
 [ You are not allowed to view attachments ]

Please check value which is named Altimeter Setting

I have exported this values by VP2 and VUE.
VP2:
Code: [Select]
Barometer: 30.011
Barometric Reduction Method: 2   - NOAA Bar Reduction. For VP2, this will always be 2.
User-entered Barometric Offset: 0
Barometric calibration number: 23
Barometric Sensor Raw Reading: 29.643
Absolute Barometric Pressure: 29.643
Altimeter Setting: 29.999

Elevation in feet: 330
Calculated Altimeter: 29.999

Vue Barometric Reduction Method: 0   - user offset:
Code: [Select]
Barometer: 29.682
Barometric Reduction Method: 0   - user offset
User-entered Barometric Offset: 0
Barometric calibration number: 65534
Barometric Sensor Raw Reading: 29.682
Absolute Barometric Pressure: 29.682
Altimeter Setting: 30.036

Elevation in feet: 328
Calculated Altimeter: 30.036

Vue Barometric Reduction Method: 1   - Altimeter Setting:
Code: [Select]
Barometer: 30.038
Barometric Reduction Method: 1   - Altimeter Setting
User-entered Barometric Offset: 0
Barometric calibration number: 65534
Barometric Sensor Raw Reading: 29.684
Absolute Barometric Pressure: 29.684
Altimeter Setting: 30.038

Elevation in feet: 328
Calculated Altimeter: 30.038

Vue Barometric Reduction Method: 2   - NOAA Bar Reduction:
Code: [Select]
Barometer: 30.050
Barometric Reduction Method: 2   - NOAA Bar Reduction. For VP2, this will always be 2.
User-entered Barometric Offset: 0
Barometric calibration number: 65534
Barometric Sensor Raw Reading: 29.684
Absolute Barometric Pressure: 29.684
Altimeter Setting: 30.038

Elevation in feet: 328
Calculated Altimeter: 30.038

Please noticed that console value Altimeter Setting is the same as my Calculated Altimeter

I have used algorithm:
Code: [Select]
// see http://www.wxqa.com/archive/obsman.pdf
        //A = (P^N + K*Z)^(1/N),
        /*
        double P = rcd.BarometricSensorRawReading/1000.0;
        int16_t  Z = davisSetup.elevation;
        double N = 0.190263;
        double K = 1.312603E-5;
        double A = pow( (pow(P,N)  + (K*Z) ),1/N);

So I will just switch in CWOP export function from Barometer to Altimeter Setting.
From WiFiLogger's firmware 2.12. CWOP will have console  Altimeter Setting value.

Offline galfert

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Re: WiFiLogger - Connect your Davis console directly to the Internet via WiFi
« Reply #873 on: February 08, 2019, 07:25:39 AM »
So I will just switch in CWOP export function from Barometer to Altimeter Setting.
From WiFiLogger's firmware 2.12. CWOP will have console  Altimeter Setting value.

Wojtek,
Excellent! Great work and very nicely documented and referenced in code. Thank you for the prompt response to this matter.
« Last Edit: February 08, 2019, 09:07:09 AM by galfert »
Ecowitt GW1000 | Meteobridge on Raspberry Pi
WU: KFLWINTE111  |  PWSweather: KFLWINTE111
CWOP: FW3708  |  AWEKAS: 14814
Windy: pws-f075acbe
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Offline DRoberts

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Re: WiFiLogger - Connect your Davis console directly to the Internet via WiFi
« Reply #874 on: February 08, 2019, 09:04:57 AM »
WiFiLogger

Thanks for not only solving the issue, but also the very quick response. I am one  who will benefit from your effort. Best to you! =D>

 

anything