Current-only measurement for emonPi

glyn.hudson · 15 August 2016 13:57

Appologies, I missed this. Yes, emonPi does not report current by default only power. You will need to modify the firmware:

https://github.com/openenergymonitor/emonpi/blob/master/firmware/src/src.ino#L263

Follow the emonlib example:

github.com

openenergymonitor/EmonLib/blob/master/examples/voltage_and_current/voltage_and_current.ino#L23


      
          
          void loop()
          {
            emon1.calcVI(20,2000);         // Calculate all. No.of half wavelengths (crossings), time-out
            emon1.serialprint();           // Print out all variables (realpower, apparent power, Vrms, Irms, power factor)
            
            float realPower       = emon1.realPower;        //extract Real Power into variable
            float apparentPower   = emon1.apparentPower;    //extract Apparent Power into variable
            float powerFActor     = emon1.powerFactor;      //extract Power Factor into Variable
            float supplyVoltage   = emon1.Vrms;             //extract Vrms into Variable
            float Irms            = emon1.Irms;             //extract Irms into Variable
          }

In the emonPi firmware change

ct1.calcVI(no_of_half_wavelengths,timeout); emonPi.power1=ct1.realPower;

to

ct1.calcVI(no_of_half_wavelengths,timeout); emonPi.power1=ct1.Irms;

This will return current instead of power

Maybe using the emonTx Shield will be easier to do what you require since uploading to an Arduino is easier.