Drive by wire and the wish to survice the experience.

[Ronald T. Webb]

Very inventive - but bogus (IMHO).

The most common thing that goes wrong with a POT is the wiper connection. That'd
kill both sides, and you're right back to no redundancy.

Keep thinking though...one time in ten "almost a good idea" turns into a GOOD
idea!

>
> One comment:
>
> If the TPS is *just* a normal pot, and you're building all the
> circutry yourself, you can easily get one level of failsafe by
> doing things a little differently. Normally you put +5 (or
> whatever) to the top of the pot, ground the bottom, and read Vs
> from the wiper. Instead, put +5 to the wiper, and use both the
> other terminals of the pot as the "top halves" of 2 separate
> voltage dividers. (i.e. put a resistor from the top of the pot
> to ground, and measure the voltage at that connection. Do
> likewise with the bottom of the pot.) Now you have 2 separate
> signals coming from one TPS, and thus a way to check A against
> B. The drawback is the signals have the funky curve of that
> type of voltage divider (you may need more bits in your A/D)
> and the relationship between A and B is a little weird. But
> almost any common pot failure mode (open, dead spot, short)
> will give A/B signals that are obviously inconsistent, and
> there's your extra safety margin.
>
> > Any recommendations of A/D sampling freq. for the TPS?
>
> And one question: Bruce (I think) mentioned an OE app using 180Hz
> sample rate on the TPS. Does anyone have an idea of the sample
> rates used for other sensors, in any other application? Mainly
> I'm thinking about MAP, but any trivia would be interesting.
>
>    Chris C.