On Fri, 22 May 2009 23:30:54 +0200, Nicola Perotto wrote:

> Hi all,
> I need to sample 32 analog (4-20mA) at 1 KHz. The required resolution is 
> 12 bit.
> Have anyone experience with the 12 bit A/D converter included in some 
> PIC, like 18F4558 or dsPIC30F3014?
> Or it's better to use some external A/D?
> TIA
>       Nicola

Are you wanting to sample at 1KHz or sample a 1KHz signal ?  If sampling at
1KHz you may need to check the datasheets for the PICs; I believe some of
them say that sample rates below 10KHz introduce significant error due to the
S/H capacitor leakage.  I think this is mentioned in the dsPIC30F family
reference, but my exposure to other PICs is rather limited.

Regards,

Pete Restall
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