[simpits-tech] phidgits + Building Guages

[Stig Joergensen]

Well Gene,

I don't understand why you need "true position" anywhere - a zero point
is good enough even for more than 360 deg.

take the artificial horizon (HSI?) where you have a ball that can turn
in both x and y space, to reset this you don't need to know that
position of either axes, just start by first turning the y and stop when
"zero" and then turn the x to zero- and it should now be proper aligned
again....

the big problem is however, the program needs to know how many steps to
reach either a full revolution or the stop, and the zero point should
only occur over 1 position not two or three.....

/Stig


-----Original Message-----
From: Gene Buckle [mailto:geneb@deltasoft.com]
Sent: 24. oktober 2002 21:57
To: simpits-tech@simpits.org
Subject: Re: [simpits-tech] phidgits + Building Guages


> > The problem is that everyone and their brother has a neat method of
> > driving a stepper motor, but nobody says anything about *feedback*
from
> > that motor.
> >
> > This is a required feature for something like an ADI or HSI and
useful for
> > something like an altimeter.  THIS is something I'd throw money at.
>
>
> Of course you need feedback to know where the darned thing is at, but
for
> instruments in general, I'm sure you only need a 'zero' setting?
>
A zero set point is good for doing instruments that have a total travel
of
less than 359 degrees.  Anything else, you're going to need true
position
feedback.

g.


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