Author Topic: Barometric pressure calibration - the role of temperature  (Read 1398 times)

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Offline Platokidd

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Re: Barometric pressure calibration - the role of temperature
« Reply #25 on: October 23, 2021, 08:55:03 AM »
 Fine Offset barometer is like a dog chasing tail. Disappointing. Guessing this can't be addressed in firmware updates?? :-({|=

Having a barometer that adjust for temps should be top of the Fine Offset wish list.
« Last Edit: October 23, 2021, 09:02:15 AM by Platokidd »
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Offline gszlag

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Re: Barometric pressure calibration - the role of temperature
« Reply #26 on: October 23, 2021, 10:23:30 AM »
Fine Offset barometer is like a dog chasing tail. Disappointing. Guessing this can't be addressed in firmware updates?? :-({|=

Having a barometer that adjust for temps should be top of the Fine Offset wish list.

Defintely on my wish list!
I am purely speculating, but because of the increased computational requirements, a firmware update might not cut it. Might need a new processor.

Maybe the next generation of consoles...

In the meantime FO machines have had some critisizim about the use of ABS and REL in our current firmware which are terms that are not really used much anymore..

I would like to see this replaced/upgraded as mentioned in Part III:

1. Elevation [above sea level]: required at initial setup to calculate elevation offset.
2. Elevation offset: automatically calculated by the weather console at initial set up.
3. Station Pressure = raw station pressure sensor calibration offset.
4. Station Pressure calibration offset [offset to correct for sensor error].
5. Temperature correction offset: 12 hour temperature rolling mean calculated automatically.
6. Altimeter/QNH: station pressure corrected for elevation.
7. SLP/QFF: station pressure corrected for elevation and temperature.


Some of the above items could be addressed with a firmware update for our current generation of consoles. As mentioned in Part IV, a fixed temperature correction/offset is the next best thing and is do-able right now. Extra field(s) in new firmware would be better.

While we wait be better consoles, I definitely encourage users to use WeeWX to do all the post processing MSLP/Altimeter/QNH calculations for you.
« Last Edit: October 23, 2021, 12:01:20 PM by gszlag »
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Offline zoomx

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Re: Barometric pressure calibration - the role of temperature
« Reply #27 on: October 28, 2021, 03:30:12 PM »
AFAIK mems barometers are temperarure corrected in internal firmware, usually you can read the sensor temperature. BMP180 and BMP280 give the temperature value.

Offline gszlag

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Re: Barometric pressure calibration - the role of temperature
« Reply #28 on: October 28, 2021, 08:11:10 PM »
AFAIK mems barometers are temperarure corrected in internal firmware, usually you can read the sensor temperature. BMP180 and BMP280 give the temperature value.
Likewise,the BMP390 can read both temperature as well as pressure.

Technical users can refer to the datasheet for more details. I could not find any references to temperature correction in the chip firmware but did find references to "temperature compensation" which presumably temperature corrects chip temperature readings based on wide ranging ambient temperatures...not to be confused with applying temperature corrections to pressure using outside temperature readings by our Osprey array temperature sensor or other remote temp sensors like the WH32.

More info found here:
https://www.bosch-sensortec.com/media/boschsensortec/downloads/datasheets/bst-bmp390-ds002.pdf
Ambient Weather WS-2000
Ecowitt GW1000/GW1100
Ecowitt WS68: Anemometer, UV/solar
Ecowitt WH40: Rain gauge
Ecowitt WH57 Lightning sensor
Ecowitt WH32E: Outside T & H sensor
Stratus Rain Gauge (manual)
Raspberry Pi 3B+ (WeeWX/CumulusMX)
Raspberry Pi Zero 2W WeeWX/MQTT/Belchertown)
---
http://weather.glenns.ca (pwsdashboard - live)
http://weewx.glenns.ca
http://glenns.ca/cumulusmx2/index.htm
---
WU: ITEHKUMM2
PWSweather.com: MBAYWX1
AWEKAS:id=15920
WINDY: Michael's Bay, Manitoulin Island
WOW: Michael's Bay

Offline zoomx

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Re: Barometric pressure calibration - the role of temperature
« Reply #29 on: October 29, 2021, 04:05:45 AM »
BME280 is selled as Pressure and Humudity sensor but it gives temperature also, altough not very accurate, usually one or two C more. I believe that it is used to compensate the pressure and humidity reading variation due temperature.

 

anything