SLAA494B May 2011 – September 2023 MSP430AFE221 , MSP430AFE222 , MSP430AFE223 , MSP430AFE231 , MSP430AFE232 , MSP430AFE233 , MSP430AFE251 , MSP430AFE252 , MSP430AFE253
As mentioned previously, the MSP430AFE25x has up to three independent sigma-delta data converters. For a single-phase system, at least two sigma-delta converters are necessary to independently measure one voltage and one current. The code accompanying this application report addresses the metrology for a single-phase system with some anti-tampering techniques. The clock to the SD24 (fM) is derived from an 8-MHz external crystal (ACLK). The sampling frequency is defined as fS = fM/OSR. OSR is chosen as 256, and the modulation frequency fM, is chosen as 1 MHz, resulting in a sampling frequency of 3.906 ksps. The SD24 modules are configured to generate regular interrupts every sampling instant.
The following are the SD24 channel associations:
A0.0+ and A0.0- | → | Current I1 | |
A1.0+ and A1.0- | → | Current I2 (Neutral) | |
A2.0+ and A2.0- | → | Voltage V1 |