Problem in reading Total Kwh(ApenergyT) in ATM90E32

[RamyaDidde]

Each phase Kwh is matching with my Reference energy meter. Total Kwh is not matching. I am reading ApenergyT for Kwh.

@CircuitSetup Please respond. With Out responding please don't close the issues as completed

ATM90E32_SPI.zip

[AbrahamAV97]

Hey there!

I've been banging my head against this issue for months—tons of manual measurements, endless testing with different codes and devices, and I finally nailed down the problem.

It comes down to two key factors:

1. Bug in the ATM90E32.cpp library
   There's a mistake in the GetImportEnergy() function that's messing up the imported energy readings:

double ATM90E32::GetImportEnergy() {
  unsigned short ienergyT = CommEnergyIC(READ, APenergyT, 0xFFFF);
  return (double)ienergyT / 100 / 3200; //returns kWh
}

That 100? Yeah, it’s actually supposed to be 10.

2. Import Energy register overflow
   The import energy register overflows at 0.2 kWh, so if you’re reading it less frequently than you should, you're straight-up losing data due to overflow.

Hope this helps anyone else struggling with the same headache!

[CircuitSetup]

@AbrahamAV97, thanks for bringing this up. I'm sorry you've spent so much time on it.

1. I looked at this again and I'm not seeing how it could be ienergyT / 10 / 3200. The resolution is 0.01CF, which means APenergyT increments 100 times for every 1CF or Meter Constant (3200).
   This can also be written as:
   APenergyT / (100 * 3200) = kWh

2. This is correct since APenergyT is a 16 bit register, and the max is 65535 / 100 / 3200 = 0.2 kWh

[AbrahamAV97]

Hi again!

I've always trusted math, but I trust my own eyes even more.

Let me share an experiment I did: with a constant consumption of 2200 watts, my calculations showed that the imported power per 5-second reading should be 0.003 kWh. However, after much observation, I discovered that the value I was getting wasn't 0.003, but 0.0003—and it wasn't just a coincidence.

By taking more frequent readings to avoid the overflow issue I explained earlier, I noticed that the register was reading values ten times lower than it should.

So, when I changed the division factor from 100 to 10, I got the correct values that matched what my SDM630 and my current clamp were measuring. (Although you're probably right that it doesn’t make sense mathematically.)

That said, my intention is not to criticize or cast doubt on the library—please don't misunderstand me! In fact, I'm very grateful for it. It's been incredibly helpful, and I just wanted to share my solution to save anyone else from the headache if they run into the same issue in the future.