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Bruce Richardson
08-17-2006, 10:50 PM
Hello all,

Need a little help understanding how to read ADCs. I'm using BS2 and the ADC1298 adc. I referred to APPKIT: "Using the LTC1298 12-bit Analog-to-Digital Converter". If I'm reading DC voltages the values read are steady. My project will require that I read 60hz AC signals (actually a half wave will make it to the ADC input). I can also read these voltages, but·these readings are all over the board (which I think I understand because·it's·mesuring·where the wave happens to be at the time I ask for the conversion). The final project will have a window of about 10 ac cycles to get the votage reading.

Should I take several readings and average (in this case will I need to control the clock or sample rate, I'm just continously looping now at what ever speed the BS2 is running)?
I have even considered filtering the halfwave input to look more pure DC.

Any of your tips will be appreciated,

Bruce

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Bean
08-17-2006, 11:00 PM
Bruce,
If you are trying to find the amplitude of the AC signal, you would be better off just applying the half-wave to an RC filter and reading the steady DC voltage that results.

Is that the intent of reading the AC signal ? If not, what IS the intent ?

Bean.

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Bruce Richardson
08-17-2006, 11:22 PM
Bean (Hitt Consulting) said...
Bruce,
If you are trying to find the amplitude of the AC signal, you would be better off just applying the half-wave to an RC filter and reading the steady DC voltage that results.

Is that the intent of reading the AC signal ? If not, what IS the intent ?

Bean.



Yes, reading the amplitude of the AC is exactly what I want.·I will be reading the voltage from a current shunt in an AC welding application. Guess I need to get working on a filter design (new challenge).

Thanks Bean,

Bruce