• State
  • Locked Locked
  • Replies 1 reply
  • Subscribers 78 subscribers
  • Views 569 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

MSP430AFE232 analog interface

Jayaram Darvemula
Prodigy 10 points
Other Parts Discussed in Thread: MSP430AFE232

Hi,

I am using MSP430AFE232 for one of my applilcation where I will be measuring load current using CT. This controller has two 24-bit Delta Sigma ADCs. Could you please help me in converting the ADC output raw data to real data using some formula. I have been trying with standard equation that uses reference voltage and number of bits, but not getting the correct data. And also if I use both of the two channels then the controller is getting damaged. The maximum voltage that will be applied to each of the channel is 150 mV (AC).

  • 0
    Guru 227245 points

    Jayaram Darvemula said:
    he maximum voltage that will be applied to each of the channel is 150 mV (AC).

    relative to what? Do both channels are 150mv relative to the same GND?
    Depending on your setup, Ch1 might be 150mv relative to GND1 and CH2 is 150mV relative to GND2, but GND1 and GND2 are 150V apart.

    You can be sure that the device isn't damaged by 150mV :)

    Jayaram Darvemula said:
    I have been trying with standard equation that uses reference voltage and number of bits, but not getting the correct data.

    Did you properly assemble the result? SD24MEM is only 16 bit, depending on SD24LSBACC, it contains the most or least significant 16 bits. The two readings overlap, depending on OSR (see 27.2.7.1 in the users guide). For OSR=32, only 15 bits result are generated (14 in unipolar mode), and these are the upper bits, so the result must be right-shifted before calculating. For OSR=1024, even more than 24 bits are generated.

    Also, the selectable gain factor is not accurate for a gain !=1. See datasheet for the actual scaling.

    On default internal clock, SD24BUFx bits must be set to maximum (if the device has a high-impedance buffer at all)

**Attention** This is a public forum