Pass analog value through cable without loss

#1 YuvaRaja

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Posted 07 February 2013 - 09:25 AM

Hi guyz..........

I want to pass the analog value through a long cable......I know In a long cable Voltage loss is occured.

So any one can suggest any IC's or any way to pass the voltage.....

Regards YuvaRaja

#2 Mario Vernari

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Posted 07 February 2013 - 12:35 PM

"long" cable...but *how* long?

Also, how is the analog value to be transfered?

Cheers

Biggest fault of Netduino? It runs by electricity.

#3 YuvaRaja

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Posted 07 February 2013 - 01:46 PM

Hi Mario Vernari...

The cable lenth approximately 10 meters.....

The analog values means an analog sensor output in voltage ( ex potentiometer)...

Regards YuvaRaja....

#4 Mario Vernari

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Posted 07 February 2013 - 02:40 PM

The simplicity or not relies on some detail. I would to know the impedance of the sensor, but probably you don't know this parameter.

Could you post a link of the sensor, so that I may understand how it's made?

If the impedance is relatively low, you could wire a simple coax cable from the Netduino to the sensor. If the impedance is med/high and/or there are sources of noise (e.g. motors, radioes, etc), you should add an amplifier to the sensor side.

Another option, in the latter case, is adding a small Arduino to convert the analog value to digital, then transfer the data via serial.

Cheers

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#5 CW2

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Posted 07 February 2013 - 04:06 PM

A standard 22 AWG (0.644 mm diameter) copper wire has resistance 52.96 m?/m, so 20 meter cable (10 m there and back) adds about 1060 m? (~ 1?) to the potentiometer resistance; if you are using common parts in k? range and typical tolerance �20%, the wire resistance is negligible.

#6 Mario Vernari

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Posted 07 February 2013 - 05:18 PM

@CW2: I mean the impedance of the sensor, not the resistance of the wiring!

Since any (long) wiring is much like as an antenna and leads to capacitive, inductive and resistive behaviors, the lower is the impedance of the generator (=sensor), the lower will be the probability to alter the signal for any parasitic influence.

Anyway, I think that the easiest way is to try, since 10mt of coax cable are inexpensive.

Cheers

Biggest fault of Netduino? It runs by electricity.

#7 Verdris

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Posted 07 February 2013 - 05:45 PM

@CW2: I mean the impedance of the sensor, not the resistance of the wiring!
Since any (long) wiring is much like as an antenna and leads to capacitive, inductive and resistive behaviors, the lower is the impedance of the generator (=sensor), the lower will be the probability to alter the signal for any parasitic influence.

Anyway, I think that the easiest way is to try, since 10mt of coax cable are inexpensive.
Cheers

Especially if the wire is to be left unshielded, it will be susceptible to 50/60Hz noise. To eliminate sensor impedance, a buffer amp could be used, I suppose. That might help clean things up.

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#8 Mario Vernari

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Posted 07 February 2013 - 06:20 PM

Especially if the wire is to be left unshielded, it will be susceptible to 50/60Hz noise. To eliminate sensor impedance, a buffer amp could be used, I suppose. That might help clean things up.

Exactly what I mean!

Thanks for pointing out.

Cheers

Biggest fault of Netduino? It runs by electricity.