[LASS Soaring] Re: AW: Why does our Picolarios refuse to read Zero Feet?

[GordySoar at aol.com]

Hi Gordy,

The reason is turn on drift of the  pressure transducer.
We get with all the calibration effort a precision of  about +- 30 feet 
maximum turn on drift.

You can easily have this  effect better, when you switch the Picolario on and 
wait 1-2 minutes.
Then  switch if off and on again and the second time the Picolario drift is 
nearly  0.
But we cannot wait after each turn on 1-2 minutes until the unit is fully  
warmed up.

By the by, here some infos about the dimensions we are  talking about.
The pressure at mean sea level is about 15 psi. A pressure  transducer has 
about 1 % temperature and other errors.
This would give us a  0.15 psi, which is around 300 ft. error.
We do a calibration in a temperature  / pressure chamber, where we first get 
the absolute accuracy (Your friend s  Picolario will show nearly the same 
values than yours) and then we do the  temperature calibration. This brings down 
temperature errors to typical around  15 ft and maximum 30 ft (which is our 
limit)

Another point: Some  people blow into the pressure silicon tube and leave 
some water there. This will  cause errors. Or any mounting of the Picolario, 
which generates mechanical  forces directly at the sensor will also generate error.

I hope this  information helps.

Let me know your  results.

Cheers
Uwe Renschler
Why does our  Picolarios refuse to read Zero Feet?
Hi,
I was at  my German friend 's house in Dallas and he asked me why his new 
Picolario  doesn't want to recalibrate to zero feet, it always reads plus or 
minus feet  when you turn it on.
I noticed mine new one does the same  thing.
Is there a setting we can change to make it more  accurate?

Thanks
Gordy Stahl
 
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://localhost.localdomain/pipermail/soaring/attachments/20061020/41130d04/attachment.htm