Author Topic: scale on basic temperature graphs  (Read 1894 times)

beachcomber

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scale on basic temperature graphs
« on: February 02, 2013, 08:21:11 PM »
I have a Davis Vantage Pro that has worked flawlessly for many years with LWC and for the last few months with Weathercat 1.0.2.

Yesterday I upgraded to WC 1.1.3 without any apparent problem but now the basic external temperature and dew point graphs start at -30F (see attachment). The internal temperature basic graph does not have the problem. The computer is a Mac Mini Intel core2duo running 10.6.8
All readings and other graphs look reasonable and for the past 24 hours the data editor shows temperatures in the 45-70F region. No comms errors.

Switching between C and F still shows this big "zero" offset (-40C and -30F origin). I know I can set the initial max range for temperature but is there any way of setting the minimum?

If I create a custom graph of external temperature, it shows a scale with a reasonable range (40 to 80F).

Any ideas what could be wrong?

Tony

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Re: scale on basic temperature graphs
« Reply #1 on: February 02, 2013, 10:05:22 PM »
Hi Tony,
The most likely cause is somewhere recently you have either a spurious low temperature (or if you have dew point and temperature linked in the prefs) a low dew point (spurious low humidity). Have a look at your daily or monthly stats - it may be there as one of the lows then edit it out with the data editor.

beachcomber

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Re: scale on basic temperature graphs
« Reply #2 on: February 03, 2013, 04:54:15 AM »
Thank you. Unlinking the external temperature and dew point fixed the immediate problem.

When I looked back through the data I did find a few series of very low dew points several days ago - presumably caused by a string of RH readings of zero from the classic Davis Vantage Pro problem of an intermittently failing sensor. I am just surprised that the external temperature graphs from WC 1.02 did not show the same -40F offset.

A question: Is there any compelling reason to link the external temperature and dew point? The primary use of the station is to provide air temperature and wind conditions to kite and windsurfers.

Tony


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Re: scale on basic temperature graphs
« Reply #3 on: February 03, 2013, 10:38:03 AM »
There's no reason to - the option links the scales of external temperature and dewpoint basic graphs - both will scale to whichever has the largest scale so when placed side by side they are easier read (custom graphs do this automatically).

beachcomber

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Re: scale on basic temperature graphs
« Reply #4 on: February 03, 2013, 06:24:43 PM »
Thanks again. That is what I guessed.
Tony