Null values for ET

[wxsprags]

Hello,

I am hoping to get some help getting my weewx to calculate the ET. Right now it just records NULL. I've tried uninstalling and reinstalling, and a few different settings in the Calculations section of the config file. I also tried a few different ways of installing pyephem (like pip2) but that didn't seem to work.

I am using:

Hardware: Acurite 01036, Raspberry Pi 3B+ with latest, up-to-date debian stretch 9

Database: MariaDB on separate NAS

Weewx version 3.9.1 with pyephem installed

Python/linux experience: beginner

Everything seems to work fine otherwise. My archive table in the mariadb is consistently filled with the default data. My default reports seem to work fine, although I do think I am getting the default almanac data - it has the Celestial sun and moon data only (I don't know if it's supposed to have more with pyephem). But ET is always NULL in the table, and is always None in the REC portion of weewx's loop:

----

LOOP:   2019-05-16 19:44:58 MDT (1558057498) altimeter: 29.7337613796, channel: 3, dateTime: 1558057498, inTemp: 61.16, maxSolarRad: 126.776693038, outTempBatteryStatus: 0, pressure: 26.24625289, rain: 0.0, rain_total: 5.5372, rainRate: 0, rssi: 3, rxCheckPercent: 100.0, sensor_battery: 0, sensor_id: 3620, usUnits: 1, windDir: None, windSpeed: 0.0

LOOP:   2019-05-16 19:45:16 MDT (1558057516) appTemp: 44.4650993723, channel: 3, cloudbase: 4814.9980207, dateTime: 1558057516, dewpoint: 40.4416051149, heatindex: 46.6, humidex: 46.6, maxSolarRad: 125.978094458, outHumidity: 79, outTemp: 46.6, outTempBatteryStatus: 0, rainRate: 0, rssi: 3, rxCheckPercent: 100.0, sensor_battery: 0, sensor_id: 3620, usUnits: 1, windchill: 46.6, windDir: None, windSpeed: 0.0

REC:    2019-05-16 19:45:00 MDT (1558057500) altimeter: 29.7337613796, appTemp: 44.4650993723, barometer: 29.7849529075, channel: 3.0, cloudbase: 4814.9980207, dateTime: 1558057500.0, dewpoint: 40.4416051149, ET: None, heatindex: 46.6, humidex: 46.6, inTemp: 61.16, interval: 5, maxSolarRad: 126.68790242, outHumidity: 79.0, outTemp: 46.6, outTempBatteryStatus: 0.0, pressure: 26.24625289, rain: 0.0, rain_total: 5.5372, rainRate: 0.0, rssi: 3.0, rxCheckPercent: 100.0, sensor_battery: 0.0, sensor_id: 3620.0, usUnits: 1, windchill: 46.6, windDir: None, windGust: 0.0, windGustDir: None, windrun: 0.0, windSpeed: 0.0

----

My current calculation section of the config is as follows:

--

#   This section controls the origin of derived values.

[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

ET = software

maxSolarRad = software

cloudbase = software

humidex = software

appTemp = software

windrun = software

--

Any help or advice would be appreciated.

Thanks!

[gjr80]

Hi,

For WeeWX to calculate ET your archive records must have outTemp, outHumidity, windSpeed and radiation data. Looking at the archive record you posted you have no radiation data. Does your station have a solar radiation sensor? If not then unfortunately WeeWX is not able to calculate ET.

Gary

[wxsprags]

Hi Gary,

I was wondering if it was something that simple... I wasn't sure if it might use the maxSolarRad or if it might be able to estimate the radiation. Unfortunately my station doesn't have a solar radiation sensor.... Thank you though... I can stop trying to get it to do what it can't do!

Thanks,

Adam