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PSoC 4 MCU

Anonymous
Not applicable

Hi all!

   

I am having trouble configuring my adc to my current sense circuit. I don't know what my sample rate should be and how the Acquisition time affects the sampling rate. I want to measure current from 0 to 2.7 Amps with a 24 Vac 60 hertz power supply. I know nyquist states the sampling rate must be twice the sampled signal (120 Hz)??? I have attached my circuit and adc configurations to this post if anyone has any suggestions.

   

Thanks,

   

Rick

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3 Replies
Anonymous
Not applicable

This attachment should help.

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HeLi_263931
Honored Contributor II

So you want to measure average current, or really get a detailed current trace? In the latter case, the sampling rate should be at least 10 times the signal frequency - then you get 10 measurements per wave. You should look at the data sheet whether the PSoC4 SAR ADC as a minimum sampling rate. You want to get the aqusition time to be as short as possible.

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Vasanth
Moderator
Moderator

Hi,

You have to have more than 10 times the signal frequency to reproduce the signal. Similarly acquisition time depends on source resistance and SAR input impedance. To calculate the acquisition time please refer page no 17 of the document provided below :< http://www.cypress.com/mwg-internal/de5fs23hu73ds/progress?id=gqruwXPjmXaFqwqhRzHYVDbo_OSUpLuZod2fVh... >. To measure the current high side current sensing method can be used. 

Best Regards,
VSRS

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