How Does Rain (archive db) Work?

[tomdotorg]

Hi,

New to this stuff, but working on getting a functional replacement for a WeatherLink-like setup using WifiLogger2. Here are the rain fields sent on every loop:

What would be the proper mapping in weewx.conf to capture (eventually) the actual correct rain for generated archive records? Does this question even make sense?

This is what I am doing (I copied the config with the intention of tweaking it) and this is clearly not right - it's raining today and my weewx shows like 20" because of my wrong mappings..

        [[[[rain15]]]]
            ignore = false # opt back in for this field
            name = rain
        [[[[rainr]]]]
            ignore = false # opt back in for this field
            name = rainRate

edit: correct data (WeatherLink) : http://vtwx.tom.org/
and incorrect MQTT as (incorrectly) configured above : https://vtwx-dev.tom.org/

[bellrichm]

We may want to bounce this by the experts in the WeeWX Google Group. Here is some background information.

The field rain in WeeWX is a delta field. Prior to a 4.x release, WeeWX did not have the concept of a cumulative rain observation and it was the responsibility of the driver or service to convert from cumulative to delta. MQTTSubscribe provides this via a conntains_total option. Also see,
issue 149

I couldn't find much documentation on it, but it appears that WeeWX now has a rainTotal field. Here is some additional info.
weewx/weewx#491 (comment)
https://github.com/weewx/weewx/blob/a55892e1d5cd41167d7eff9635f5a1750ad2a850/bin/weewx/wxxtypes.py#L557

Net, I think this is what you want

        [[[[rain15]]]] # assuming this is cumulative for 15 minutes??
            ignore = false # opt back in for this field
            name = rainTotal

Not sure which cumulative field makes the most sense...

[tomdotorg]

Thanks, Rich. I will construct a question for the weewx group.

[tomdotorg]

Quick non-update. I am still reading up on this, but it is slow going as I am not a Python expert. Stay tuned..

[tomdotorg]

@bellrichm quick question: is it possibly as easy as choosing one of the cumulative rain fields (rain15, 1h, etc.) and mark it as contains_total? So something like this:

        [[[[rain15]]]]
            ignore = false # opt back in for this field
            contains_total = true
            name = rain

[bellrichm]

Yes, that should work. I was only pointing out that WeeWX now natively supports it. When, I get some time, I'll see if I can figure out how to use the native WeeWX support

[bellrichm]

Quick non-update. I am still reading up on this, but it is slow going as I am not a Python expert. Stay tuned..

If you get stuck, don't hesitate to ask. Questions also help to point out where the documentation needs more work.