SLAA494B May 2011 – September 2023 MSP430AFE221 , MSP430AFE222 , MSP430AFE223 , MSP430AFE231 , MSP430AFE232 , MSP430AFE233 , MSP430AFE251 , MSP430AFE252 , MSP430AFE253
The SD24 converter has a fully differential input and, therefore, no added dc offset is needed to precondition a signal, which is the case with most single-ended converters.
The output of the SD24 is a signed integer. Any stray dc offset value is removed independently for V and I by subtracting a long-term dc tracking filter's output from each SD24 sample. This long-term dc tracking filter is synchronized to the mains cycle to yield a stable output.
The resulting instantaneous voltage and current samples are used to generate the following information:
These accumulated values are processed by the foreground process.