REFLECTOR: FW: AeroElectric-List: "Flicker Filter" for low fuel warning float switches?

[Chuck Jensen]

Some of you monitor the AeroConnection but for those that don't, Nuckols
is putting together a neat little switch that would fix the 'low sump'
warning light flicker that some have been plagued with.  This little
sensor would not allow your alarm light to illuminate until the sump
indication is on more than (pick a number) 50% of the time for a set
period of time, hence temporary or intermittent alarms would be ignored.

Thanks,
Chuck Jensen


-----Original Message-----
From: owner-aeroelectric-list-server at matronics.com
[mailto:owner-aeroelectric-list-server at matronics.com] On Behalf Of
Robert L. Nuckolls, III
Sent: Monday, January 23, 2006 4:17 PM
To: aeroelectric-list at matronics.com
Subject: Re: AeroElectric-List: "Flicker Filter" for low fuel warning
float switches?

--> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
<nuckollsr at cox.net>   float switches?

At 03:45 PM 1/23/2006 -0500, you wrote:

>--> AeroElectric-List message posted by: "Dr. Peter Laurence" 
><Dr.Laurence at mbdi.org>
>
>
>
> > Some months ago, someone was asking about a circuit to
> > make the float-switches in their airplane be a bit more
> > definitive as to when the low fuel warning light was
> > illuminated.
> >
> > I have hardware in hand that can be programmed to accomplish
> > this task. We can watch for switch behavior to exhibit
> > some characteristic like "switch closed more than 50% of the time
> > over a 1 minute period" before the warning light is latched
> > on. Given the flexibility of software, we can probably address
> > any other low-fuel trip protocol.  Does anyone have a need for
> > this capability?>
> >
> >        Bob . . .

   Do I understand correctly that a LOW FUEL condition is detected
   by a CLOSING switch? Is there any problem with having the flicker
   filter pulling lamps to ground to illuminate them?

   The way the hardware is currently configured, float switches will
   pull an input to ground as the fuel level goes down. The present
   control algorithm I'm considering is to ignore the "flickering
   switch" until it has been closed for more than 50% of the last
   minute. When this condition is reached, the output pin for that
   channel latches low (pulls annunicator light to ground).

   The light will go out when the fuel level switch has been open
   continuously for some period of time . . . say one minute.

   If this sounds like something you could use, I'll put it in the
   hopper that holds my software manager's tasks . . .

   Another question, what kind of switches are you using?  Hall
   effect sensors would be ideal, totally enclosed reed switches
   would be second best.


        Bob . . .


      < What is so wonderful about scientific truth...is that >
      < the authority which determines whether there can be   >
      < debate or not does not reside in some fraternity of   >
      < scientists; nor is it divine. The authority rests     >
      < with experiment.                                      >
      <                            --Lawrence M. Krauss       >
                   http://www.aeroelectric.com




_-============================================================
_-=          - The AeroElectric-List Email Forum -
_-= Use the Matronics List Features Navigator to browse
_-= the many List utilities such as the Subscriptions page,
_-= Archive Search & Download, 7-Day Browse, Chat, FAQ,
_-= Photoshare, and much much more:
_-=                                              
_-= --> http://www.matronics.com/Navigator?AeroElectric-List
_-============================================================
_-=             - List Contribution Web Site -
_-=   Thank you for your generous support!
_-=                              -Matt Dralle, List Admin.
_-= --> http://www.matronics.com/contribution
_-============================================================