Problem While reading AC current using Shunt Type with SADC

[avinashbhavsar]

I am working on Energy Meter Micrcontroller IC  #MKM34Z256VLQ7 

Now I am stuck while reading  current  parameter from  SADC 24 bit   and  getting SADC count with more variation and not seen any repetition while testing with 0 to 500mv

I have tested  rang of  0 to 500mV voltage by applying  DC volt and its working well with this with no variation  .

But variation occur with the AC voltage given to circuit .

Please help if some have any idea about this .

Hardware reference DRM122.

[avinashbhavsar]

Hi kerry Zhou ,

Happy to tell you that Problem is sloved , Hardware is completely ok ,There is problem is AFE driver side .

Thank you .

Avinash .

[kerryzhou]

Hi Avinash,

   Congratulations to you! :smileyhappy:

   If have the new question in the future, welcome to create the new question post!

Have a great day,
Kerry

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[kerryzhou]

Hi Avinash Bhavsar,

     You said the DC volt works OK, but the AC volt can't work.

    Do you use the oscilloscope to test the AC wave? Test the wave between GNDA to LINE_OUT, and GNDA to LINE_IN, and LINE_IN to LINE_OUT.

    You need to make sure the input AC wave is clean, don't have too many noise.

    You can test the wave, and also share me your AC wave.

    Besides, how do you connect your AC gnd to this KM32 board? From my own experience, the ground signal is also very important.

Have a great day,
Kerry

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[avinashbhavsar]

Hey Kerry thank you for your reply ,

I am getting some problem when I used to connect  the  AC signal to my oscilloscope, Instate of that I used the hardware which is given in  reference document DRM122, I also attach  same copy with above question .

AC gnd to this KM32 board I have attach as like the phase .

Do you have any other way to get this SADC data ?

Thank you .

Avinash Bhavsar

[kerryzhou]

Hi Avinash Bhavsar,

   What's the problem when you connect the AC signal to your oscilloscope?

   If the AC voltage is very high to ground, it's better don't connect your oscilloscope power GND, then you can test the AC signal.

Have a great day,
Kerry

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