Wrong barometer value displayed - weewx-interceptor with smarthub

[Sylvain Martel]

Weewx is not storing/displaying the correct barometer value.  I have an Acurite Smarthub and my guess is that the "offset" is being ignored.

Since I am using the weewx-interceptor driver, the Acurite section is not used in weewx.conf, so "use_constant" doesn't fix this.  Does anyone knows how to get the correct barometer value using that driver?  I browsed the doc on github withotu finding anything.

Thanks

[Andrew Milner]

you could always just adjust the barometer value using the corrections in the StdCalibrate section of weewx.conf

http://weewx.com/docs/usersguide.htm#StdCalibrate

[Sylvain Martel]

After some more digging, I can confirm that the value displayed in weewx is the value without the sea-level adustement.  If I was to try to include the fix in StdCalibrate, what is the formulae I should use? 

[Andrew Milner]

So you should map the pressure reading to pressure rather than to barometer.

[Sylvain Martel]

That seem to have worked. I added this in the StdCalibrate section

barometer = pressure

and now the reported value is the right one.

thanks!

[Andrew Milner]

are the values for altimeter, barometer and pressure all correct in the database??

which value(s) are actually provided by the station??

You should have three different values in the database for pressure, altimeter and barometer.

[Sylvain Martel]

Dunno(I'm pretty new to all this)

Before the "fix" here are the value in the database:

    Barometer                       Pressure            Altimeter

31.0840997823434            30.16                31.061976388455

And after

    Barometer                       Pressure            Altimeter

30.18

30.18

31.0824641818824

Before the fix, the Barometer value didn't fit with what my.acurite was reporting, always a good 30 hPa higher. 

Then I found this website https://barani.biz/apps/sea-level-pressure/ and foudn out the reported value by weewx was not taking into account sea-level.  If I used their tool and entered my elevation, the final result was the same as my.acurite.

[Andrew Milner]

As you can see you now only have two discrete values rather then the 3 you should have.

Your 'fix' is not the correct fix.

You need to determine which of the three values is being picked up by the interceptor and in the interceptor section of weewx.conf map that value to the appropriate weewx column.  I suspect you are receiving 'pressure' so you should set that in the field map and let weewx calculate barometer and altimeter.  Weewx knows your altitude (it is in weewx.conf).

[Sylvain Martel]

Indeed, I finally figured it all.  I removed the fix, which indeed wasn't one, and finally figured out why the value aren't the same.  It's because... they aren't the same.  Acurite report Pressure, Weewx reports Barometer.  All that was required was to change the template to display the Pressure($current.pressure and $trend.pressure)

I felt stupid :P  But hey, I learned alot about weewx in the process!

Thanks!