Sudden pressure drop

[Orion]

Had this strange pressure reading between 17.36 and 17.41 did not notice for about an hour
Rebooting PC Cured It
checked the data from easyweather after rebooting and the station history was normal
but cumulus graph had dropped from 1018 to 1006, back to normal after reboot
also data on Weather underground is incorrect
any ideas ?

Roy

[steve]

Did the drop occur after a restart of Cumulus? If so, it's likely that when Cumulus read the pressure 'offset' it got garbage so ignored it, and you ended up with absolute pressure. Does the drop correspond to your normal offset?

http://wiki.sandaysoft.com/a/FAQ#My_pre ... dropped.21

If it wasn't just after a restart, then I'm afraid I have no idea what caused it.

[Orion]

Hi Steve
The pressure dropped about an hour before i restarted cumulus
the data on the FO station is fine
needed to reboot PC to get back to normal

This line is now missing from cumulus.ini

Code: Select all

EWpressureoffset=8.2

when I install a new build do I need to put it back in again. ?

[steve]

This line is now missing from cumulus.ini

Code: Select all

EWpressureoffset=8.2

when I install a new build do I need to put it back in again. ?

Do you mean that you had previously added that line, but now it has disappeared? The installer doesn't overwrite cumulus.ini, and I can't think of any way that a line would get removed. You should never need to reinstate a line that you'd previously added or changed.

Could you zip up the diags folder and attach it, please, and I'll see if I can see anything funny going on.

[Orion]

Hi Steve
I added the offset line about a month ago
but it has now disappeared, so I have just put it back again
here are my diags
Many thanks
Roy

[steve]

The pressure drop occurred just after you restarted Cumulus, so it was indeed the problem of the offset being corrupted when it was read at start up:

06/02/2011 17:41:54.784 : EWUSB: Read pressure values: rel=1005.9 abs=1010.5 offset =-4.6

[Orion]

Thanks Steve
Will check that the offset is still in the cumulus.ini next time I install a new build

[steve]

OK, thanks. Do you happen to have any other "ini-file only" settings, and if so, are they still there?

[Orion]

The EWpreasure offset is the only thing that i have added/changed
will keep a eye on it next time

[fractonimbus]

I saw a similar pressure drop the other day (5-6 Feb), not related (as far as I recall) to restarting Cumulus (though I can't rule that out). The drop was from ~1015 mB down to ~1001, quite similar to yours, Roy. Since I'm at ~600 metres, the absolute pressure is lower than 1001. The drop was for about the same length of time starting a bit before midnight AEST (UT+11).

fracto