>The Dynon requires a 0-5 volt varying input
Richard - OK, that's clear enough, and you can generate that 0-5
volts in a number of ways, typically by using a potentiometer
(variable resistor network).
>the probes are capacitance
>type from Pete at Airworld ie resistive type
But that's not very clear. Either they are capacitive or resistive.
Maybe their sensing mechaism is capacitive and the interface to the
display is resistive? You don't seem to say what this sensor is
intended to measure.
>Dynon have advised their
>resistance to voltage converter is not suitable
If the output of the sensors is capacitive then that would be a
sensible answer. Even if the sensor output is resistive, it might
also be correct if the range of resistance falls outside what the
Dynon converter is designed to handle. Do you have the spec of the
Dynon converter?
>I know some of you are worldly wise in the electrics side
I have done a bit of electronics, but I'd need a bit more information
before being able to offer advice.
The sensor in question, how is it specified? Assuming it's a
2-terminal device, I'm looking for the range of capacitance (or
resistance as the case may be) that it presents to the outside world
for the full range of input conditions. It does seem much more likely
that the output is resistive - a variable capacitance would require
rather more interface work - so the spec would be something like: X
ohms at minimum (pressure, temperature, level, whatever) to Y ohms at
maximum (pressure, temperature, level etc).
If it's a simple 2-terminal variable resistor, we can design a
potentiometer circuit to provide the Dynon with the 0 - 5 volts that
it wants to see, provided also that the Dynon input impedance is
known (or alternatively is so high that is can be neglected).
The approach above is from first principles, without knowing very
much about the devices involved. Maybe someone with direct experience
of the sensor and the display can offer more succint advice.
I've removed the rest of the text from this hijacked thread as it's
not relevant!
regards
Rowland
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| Rowland Carson LAA #16532 http://home.clara.net/rowil/aviation/
| 1270 hours building Europa #435 G-ROWI e-mail <rowil@clara.net>
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