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    AC Current Measurement with PRoC and ACS712

      Hello colleagues,


      I am trying to measure AC current with your PRoC (Eval Kit) and the Allegro's ACS712 but I can just measure noise. I am using the ADC SAR Block with 4.8Vdc as reference and very fast sampling (125ksamples per second). The ADC SAR block screenshots are attached and below is the code:


          if (count == 0)


          readValue = ADC_SAR_SEQ_GetResult16(0);    // Channel 0 is connected my pin to the ACS712 output
          if (readValue > max)
              max = readValue;
          if (readValue < min)
              min = readValue;
          if (count >= 25000) // 0.2 seconds


              mamp = 2.5*(max-min); // (1000*0.353*4800)/(4095*166)=2.5   // 1000 is A to mA, 0.353 is from Vpp to Vrms, 4800mV is Vref, 4095 are the bits of resolution and 166 is the mV/A given by my ACS712 


      The root problem is that Max and min values are always almost the same (0x5D and 0x5B), no matter which load (no load, 30mA, 200mA or 350mA) is connected. I think the ADC SAR is not really sampling so fast and that's why I measuring always the same, does any of you have an idea of what can be happening?


      Thanks in advance,



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