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Pressure drop

Posted: Wed 27 Jul 2011 10:01 pm
by Ned
I switch my PC off every night. On looking at the pressure graph this morning I see a sudden drop of 13 hPa between the two readings when Cumulus was on and the next (5 mins later) when Cumulus had been shut down.

The console is still delivering good pressure values, comparing to the nearby airport but Cumulus is showing a difference of -15.3 hPa and not -2.5 which is the calibration I have applied in Cumulus (I prefer this method over correcting the console).

I've been running 1005 for a few days, no probs and loving the 'synchronised' upload times :D

cheers

Re: Pressure drop

Posted: Wed 27 Jul 2011 10:26 pm
by mcrossley
Ned, have you set a "EWpressureoffset=" in Cumulus.ini, that should stop the values varaying between restarts.

http://wiki.sandaysoft.com/a/FAQ#Cumulu ... et_console

Re: Pressure drop

Posted: Wed 27 Jul 2011 10:46 pm
by Ned
Mark, is that the same as calibrating the pressure within Cumulus? I had a look in cumulus.ini and there's no entry for that. But the change in pressure (13hPA) was much greater than the 2.5 correction I apply.

Anyway, I have just restarted Cumulus again and the pressure has jumped back to where it should be! It's a mystery, at least until Steve gets on the case :D

Re: Pressure drop

Posted: Thu 28 Jul 2011 7:22 am
by steve
Ned wrote:I had a look in cumulus.ini and there's no entry for that.
That's why the FAQ says you have to add it.
Ned wrote:It's a mystery
It's the problem in the FAQ that Mark referenced. Cumulus was unable to read the sea-level correction from the station (i.e. the difference between your absolute and relative pressures).

Re: Pressure drop

Posted: Thu 28 Jul 2011 9:01 am
by Ned
Thanks. I arrived at a value which gives a valid pressure reading, then forced a reread of the station readings back to last night and all seems well ... so far ;)