Re: Help please, problems reading analog samples

Hello,
El Lunes, 20 de Octubre de 2003 09:09, escribió:
> On Saturday 18 October 2003 18:39, Luis Martinez wrote:
> > Hello,
> >
> > I am trying to get analog to digital conversion from a 0V to 10V output
> > from a sensor.
> >
> > Although with a voltage tester the output of the signal is stable (the
> > sensor is allways measuring the same for testing), when I read it with
> > comedi I have an unstable read.
>
> Please give us numbers about how unstable it is. It may be normal noise.

My system has a resolution of +- 0.25mV while the unstable read I get goes 
+-150mV and it does not seem to follow a pattern (it does not seem a wave).
Also when I read the input with a volt meter I get a variation of only 1mV or 
total stable read (the resolution of the volt meter is +-1mV.

I have used an analog signal conditioner to avoid noises and I have got the 
same results.

Please help.

Luis

>
> > Also if I read another channel that is not
> > used (no signal on it) I have a value similar to the one I get on the
> > channel of the sensor.
>
> This is ok. If the other channel is loose, it will get inducted currents
> from the used channel. I get similar values in all the other channels of
> the board, when they are loose.
> Greetings,
> Ivan Martinez

Luis			

Received on 2003-10-20Z07:57:16