Pressure

[erla]

Hello all,

I just bought WH1080 weather station and now i have problem with cumulus software.
Cumulus software displaying different pressure than WH1080.
Now WH1080 pressure is 1011,9 hPa and cumulus showing 1004,1 hPa.
Do you have any idea what causing this problem.

[steve]

Have you set your station correctly to show sea-level pressure at your location? What offset did you use? Are you comparing the absolute or relative pressure on the station with the pressure in Cumulus? Cumulus always shows sea-level (relative) pressure, but this requires you to have set your station up correctly.

If you believe you have set your station up correctly, it could be this problem, in the FAQ: http://wiki.sandaysoft.com/a/FAQ#Cumulu ... et_console

[erla]

Thanks Steve,

WH1080 showing absolute pressure on the screen, that was the problem.

[steve]

Are you sure you have your relative pressure set correctly? Normally absolute pressure is less than relative pressure - they're equal at sea-level, and then absolute pressure decreases with altitude. You may be below sea-level, of course, or your station's absolute pressure is reading too high and you're compensating?

[EvilV]

Thanks Steve,

WH1080 showing absolute pressure on the screen, that was the problem.

That caught me out for five minutes too. I was pretty disappointed when my station came up with about 8 millibars less than the neighbouring ones. Then I twigged what it was, although at first I thought the relative adjustment was just a way of calibrating tacky instruments. Then I did some reading and realised what it was all about.