What has always puzzled me.
According to the specifications of the sensor the uncertainty in the
initial zero offset is +/- about 25 % of our full scale of 0.5 psi (35
cm of water). Which in the general case would require a generous bias
(using an opamp) to the output of the instrumentation amplifier.
Ofcourse, maybe Honeywell is way too pessimistic in its specification.
Tony K must have decided so?
Jan de Jong
On 11/27/2013 7:30 PM, Paul McAllister wrote:
> Hello everyone,
>
> I have been using this in my aircraft since 2004. Tony K did the
> original design work and it is based on a PIC micro processor. It is
> calibrated in 1/10th increments from empty to full and displays on a
> 10 segment LED or an analogue display.
>
> There isn't any PCB design and most people who have built them seemed
> to have trouble in getting them up an running. It's not complex to
> build but they do require a bit of tinkering to get them working,
> installed and calibrated. In my case I set up a water manometer on my
> bench to get it debugged and working.
>
> The only issue I have had is that despite having a static vent on the
> differential side, the gauge does read high when climbing and low when
> descending and it takes a few minutes to stabilize in these scenarios.
> It hasn't been enough of a problem for me to bother with trying to fix
> it. Other than this it has functioned reliably for the last 9 years.
>
> I use this in conjunction with my fuel totalizer and I do not have a
> sight gauge.
>
> I do have the source code so I could burn some PIC's for people, but
> before doing this I will need Tony K's permission. I guess if there
> was enough interest I could create a PCB design and build a batch of
> them. I will need to think on this some more before I sign up for
> this. :)
>
> Regards, Paul
>
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