Thanks.

I have an impression that executing the math routines of square and root are
a little difficult for the chip that I use. But I will try to get around by
using additions and lookup table.

Thanks again.

Tony



----- Original Message -----
From: "Douglas Butler" <dbutler@IMETRIX.COM>
To: <PICLIST@MITVMA.MIT.EDU>
Sent: Wednesday, February 27, 2002 10:44 AM
Subject: Re: [pic] Math Question - Measuring AC Voltage


> There are many ways to measure AC voltages.  The most common is RMS
> which is the usual 220VAC (110VAC USA).  RSM voltage is litterally "Root
> Mean Square", so you square your readings, average them over one cycle,
> and take the square root.  It would help if you could sync your readings
> to the zero crossings of the power line.
>
> Sherpa Doug
>
> > -----Original Message-----
> > From: Tony Pan [mailto:weidong.pan@VERIZON.NET]
> > Sent: Wednesday, February 27, 2002 9:56 AM
> > To: PICLIST@MITVMA.MIT.EDU
> > Subject: [pic] Math Question - Measuring AC Voltage
> >
> >
> > Hi,
> >
> > I want to use a pic to measure AC line voltage. First, my
> > hardware scales
> > down 200V to 5V and flips the negative duty cycle to positive
> > so that the
> > pic can read the signal. Then the pic reads the voltage every
> > 0.1ms with an
> > adc port. Now I have many almost 100 reads within a duty
> > cycle. No this is a
> > math question: How do I calculate the AC voltage from these reads?
> >
> > Thanks,
> > Tony
> >
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>

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