MQTT missing information?

[Philippe]

I am quite new to the world of weather station. I own a MISOL HP2550 station and initally connected to Wunderground.

I am now using Weewx to collect all the data locally and I am using the MQTT extension to sent it to my HomeAssistant instance.

It all works well except that I have noticed that some info are missing. For example it doesn't look like the Wind Direction is sent

Could someone point me in the right direction to activate it? Also how can I find out what all parameters means. I suspect if you know about weather it makes sense but I don't

For example what is ET_cm ?

Here is the result of the interceptor.py program where I can see that windDir is present.

identifiers: {}
raw data: PASSKEY=89C4AC8B9F2FBFBE07315A85FBA7EC52&stationtype=EasyWeatherV1.4.4&dateutc=2019-11-24+21:24:38&tempinf=70.0&humidityin=58&baromrelin=29.371&baromabsin=29.371&tempf=52.9&humidity=78&winddir=221&winddir_avg10m=221&windspeedmph=0.0&windspdmph_avg10m=0.0&windgustmph=0.0&maxdailygust=0.0&rainratein=0.000&eventrainin=0.000&hourlyrainin=0.000&dailyrainin=0.000&weeklyrainin=0.000&monthlyrainin=0.280&yearlyrainin=0.280&solarradiation=0.00&uv=0&wh65batt=0&wh25batt=1&freq=433M&model=HP2550_V1.5.4
raw packet: {'wind_speed': 0.0, 'humidity_in': 58.0, 'temperature_in': 70.0, 'wind_gust': 0.0, 'humidity_out': 78.0, 'uv': 0.0, 'radiation': 0.0, 'rain': None, 'dateTime': 1574630678, 'pressure': 29.371, 'temperature_out': 52.9, 'wind_dir': 221.0, 'rain_total': 0.28, 'usUnits': 1}
mapped packet: {'pressure': 29.371, 'outHumidity': 78.0, 'UV': 0.0, 'radiation': 0.0, 'rain': None, 'dateTime': 1574630678, 'windDir': 221.0, 'outTemp': 52.9, 'windSpeed': 0.0, 'inHumidity': 58.0, 'inTemp': 70.0, 'windGust': 0.0, 'usUnits': 1}

and here is what I receive with MQTT. As you can see no windDir.

weather/loop {"cloudbase_meter": "549.114846164", "outHumidity": "78.0", "pressure_mbar": "994.666861948", "rain_cm": "0.0", "interval_minute": "5.0", "barometer_mbar": "1005.10604387", "dewpoint_C": "7.9050189981", "windG
ust_kph": "0.0", "heatindex_C": "11.6111111111", "dayRain_cm": "0.66808", "inDewpoint_C": "12.5178362316", "windrun_km": "0.0", "altimeter_mbar": "1004.7078293", "windchill_C": "11.6111111111", "appTemp_C": "11.12349861",
"outTemp_C": "11.6111111111", "humidex_C": "11.9811045482", "rain24_cm": "0.66808", "maxSolarRad": "0.0", "hourRain_cm": "0.0", "inTemp_C": "21.1111111111", "windSpeed_kph": "0.0", "usUnits": "16.0", "UV": "0.0", "rainRate
_cm_per_hour": "0.0", "dateTime": "1574631000.0", "ET_cm": "0.0", "inHumidity": "58.0", "radiation_Wpm2": "0.0"}

[Xant]

First, lets clarify that MQTT is not the data interface between software and hardware, but the driver. Driver is the "translator" and must correlate among the many different brand names and models to a data that the software "can read and understand". That said, some extra parameters might be listed at times (as the driver may have to address diverse range of models) which might not be in direct reference to your specific PWS.

For example, the only PWS I'm aware capable of broadcasting ET (EvapoTranspiration) data is Davis Instruments. So, just disregard ET.

I'm not familiar with MISOL, but your model seems another clone of Fine Offset HP2550 (Chinese OEM), which it is sold under many different brands (including Ambient Weather WS2000, WH2900, WS2902A or Ecowitt HP2550, WH2910c). That said, and checking WeeWX compatibility hardware, it seems that your PWS indeed supported by the Interceptor driver.

'windDir" obviously an important parameter and it should have a direct correlation to your system, assuming that you are working with the correct driver. As I see 'windSpeed = 0', wouldn't be that direction is then disregarded by the driver as there is "no wind"? That is, please re-check data upon having actually wind.

Xant

[Philippe]

Hello Xant,

Thank you  for your answer. YOur point about having no wind is a fair point. The station is at the moment in my conservatory while I decide where to install it outside. So at the moment there is indeed no wind. I will try to put it outside tomorrow and see what happens.

What I can see is that Ecowitt.net and Wunderground are able to report a direction (SW) but as you say it is possible that the MQTT driver works differently.

I will report my findings tomorrow

[Philippe]

You were correct in your assumption Xant

I put the weather station outside and now the Wind Direction is reported via MQTT

{"cloudbase_meter": "203.252309503", "outHumidity": "94.0", "pressure_mbar": "981.011251698", "rain_cm": "0.0", "interval_minute": "5.0", "barometer_mbar": "991.312169844", "dewpoint_C": "10.5398960463", "windGust_kph": "3.5405568", "heatindex_C": "11.4722222222", "dayRain_cm": "0.02794", "inDewpoint_C": "10.3623894371", "windrun_km": "0.050292", "altimeter_mbar": "990.937191397", "windchill_C": "11.4722222222", "appTemp_C": "11.5492484422", "outTemp_C": "11.4722222222", "humidex_C": "13.0041999121", "rain24_cm": "0.02794", "maxSolarRad": "145.740512944", "hourRain_cm": "0.0", "inTemp_C": "18.0", "windSpeed_kph": "0.603504", "usUnits": "16.0", "UV": "0.5", "rainRate_cm_per_hour": "0.0", "dateTime": "1574774100.0", "windDir": "283.0", "ET_cm": "0.00032110245162", "inHumidity": "61.0", "radiation_Wpm2": "95.4825"}

Thank you for your advice

[Xant]

Philippe

Glad the puzzle is solved. It makes sense as if there is no wind (ie, windspeed = 0), there is no data (empty), as "zero degrees" is actually a direction and would interfere in any average calculation.

Interesting enough, ET - EvapoTranspiration (which is sort of "reverse rain") also showing data and I'm now curious if hardware or software calculated. That is, "hardware" refers to PWS, while "software" refers to WeeWX.

Please, verify into "weewx.conf" if you have ET listed under Calculations as the following:

[StdWXCalculate]

    

    [[Calculations]]

        # How to calculate derived quantities.  Possible values are:

        #  hardware        - use the value provided by hardware

        #  software        - use the value calculated by weewx

        #  prefer_hardware - use value provide by hardware if available,

        #                      otherwise use value calculated by weewx

        

        pressure = prefer_hardware

        barometer = prefer_hardware

        altimeter = prefer_hardware

        windchill = prefer_hardware

        heatindex = prefer_hardware

        dewpoint = prefer_hardware

        inDewpoint = prefer_hardware

        rainRate = prefer_hardware

        maxSolarRad = software

        appTemp = software

        ET = software

X

[Philippe]

Hello Xant,

ET is Reverse Rain? now I am intrigued and will need to learn more about it. It is basically humidity from the ground evaporating that will create cloud and rain later?

Anyway here is the sectin you asked for. No mention of ET.

StdWXCalculate]
   
    [[Calculations]]
        # How to calculate derived quantities.  Possible values are:
        #  hardware        - use the value provided by hardware
        #  software        - use the value calculated by weewx
        #  prefer_hardware - use value provide by hardware if available,
        #                      otherwise use value calculated by weewx

        pressure = prefer_hardware
        barometer = prefer_hardware
        altimeter = prefer_hardware
        windchill = prefer_hardware
        heatindex = prefer_hardware
        dewpoint = prefer_hardware
        inDewpoint = prefer_hardware
        rainRate = prefer_hardware

The only place ET is mentionned is in the [[[Labels]]] [[[[Generic]]]] where it says "ET=ET"

[Xant]

1) Hardware calculation

I'm now curious if this price range system is providing ET. As the owner of this system, I leave that to you to investigate further and let us know. Is there reference in the system manual, website, display, or other?

2) ET - EvapoTranspiration

ET is defined as the amount of evaporation that would occur if a sufficient water source were available. That is, EvapoTranspiration is considered the net result of atmospheric demand for moisture from a surface and the ability of the surface to supply moisture. Surface, air temperatures, insolation, humidity and wind all affect ET. A dryland is a place where annual potential evaporation exceeds annual precipitation (ie, ET is "an inverse" of rain). 

• Davis Instruments derived weather variables (PDF): https://www.davisinstruments.com/product_documents/weather/app_notes/AN_28-derived-weather-variables.pdf
• Step by Step Calculation of the Penman-Monteith Evapotranspiration; Lincoln Zotarelli et others, University of Florida [2018]: https://edis.ifas.ufl.edu/ae459
  
• Guidelines for computing crop water requirements - FAO Irrigation and drainage; FAO - Food and Agriculture Organization of the United Nations [1998]: http://www.fao.org/3/x0490e/x0490e00.htm
  

As a "newer" weather derived variable, for most of us ("weather enthusiasts") still a curiosity, but getting much traction as it continues to be further adopted to hardware and software. Most indeed, for those in irrigation, drainage and agriculture.

As "reverse rain", to note that the units of measurement in "mm/in".

X

[Philippe]

I really don't know where the ET comes from. I checked the manual and it doesn't mention it at all.

On the screen there is no area for it either.

I am using the interceptor.py  to connect the station to weewx so it might be that  that does it but I would not know where to look.

Ecowitt.net and Wunderground themselves don't seem to be collecting that data.

As I understand weevx uses a interceptor.py to connect to my device (weevx.conf has device_type=observer). I assume that interceptor sniff the network for some data coming from the weather station.

From there the data are either coming from the station or is calculated. Since the data from interceptor.py doesn't contain ET I have to assume it is calculated but...where?

There are actually other parametes that I am not sure where they are coming from such as:

cloudbase_meter

[Xant]

Interesting.... ET and CloudBase are WeeWX calculations (http://www.weewx.com/docs/usersguide.htm#[[Calculations]] ). Thought that required trigger command in 'weewx.conf', but apparently not and calculated by software by default.

X

[Philippe]

Well if anything the link you provided confirms that when there is no wind then no wind direction is broadcasted by default.