AC Current And Voltage Measurment using the BS2
McCordPD
Posts: 4
I posted a while back about this topic, and was pointed in the right direction I think, but not exactly what I was looking for...
For voltage (120v/240v) I am going to use the voltage from my 120v/240v-9v step-down transformer (that will power the rectifier/regulator for the stamp circuit), two diodes to rectify the 9vac and a voltage divider to reduce that to less then 5v, I was then thinking of using a ADC0831 A/D to convert that to serial data for the stamp... after some playing with the values of the resistors in the divider, and some scaling of the data in software I think this will work... Any comments?
For AC current, I am going to use a 25A current to voltage transducer that will have either a 0-4v or 0-2.5v output (the 0-2.5v is nice as it only needs a 5v supply voltage, the 0-4v needs 15v) the output of this will also be fed into an ADC0831 A/D (or possibly another channel of a multiple channel version). This will also need some messing with software to calibrate... Any Comments?
Thanks...
For voltage (120v/240v) I am going to use the voltage from my 120v/240v-9v step-down transformer (that will power the rectifier/regulator for the stamp circuit), two diodes to rectify the 9vac and a voltage divider to reduce that to less then 5v, I was then thinking of using a ADC0831 A/D to convert that to serial data for the stamp... after some playing with the values of the resistors in the divider, and some scaling of the data in software I think this will work... Any comments?
For AC current, I am going to use a 25A current to voltage transducer that will have either a 0-4v or 0-2.5v output (the 0-2.5v is nice as it only needs a 5v supply voltage, the 0-4v needs 15v) the output of this will also be fed into an ADC0831 A/D (or possibly another channel of a multiple channel version). This will also need some messing with software to calibrate... Any Comments?
Thanks...
Comments
As for the voltage measurement, the point you use to pick off the the signal representing the AC input will have to be DC, of course, but you can't have too much filtering or you won't see the faster variations in the AC. Have you got the circuit you're going to use?
AC current choice is good. If the 0-2.5 volt system gives you enough resolution, it will simplify things.
The LTC1298 ADC works well with stamps, gives 12-bit resolution and has two channels. There may be an app note on the parallax site.
Cheers
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Tom Sisk
http://www.siskconsult.com
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