No, we’re not [talking about different things]. Measured on a multimeter, I’d expect to see only the d.c. component, i.e. approx. 0.5 V; or if you have a really smart one, you can probably measure the a.c. and d.c. components separately.
If I see ~ ¼ V and no a.c. is reported, the a.c. adapter still works on another emonTx4, then the input is being dragged down and the signal clipped into oblivion, by what I don’t know, hence I’m asking for the supply voltages.
What’s a bit puzzling is the processor still runs.
And if your 0.297 V a.c. is at 240 V (I can’t remember the number, though I did calculate it a while ago), then if Alexandre’s 0.255 V is the a.c. component, it represents a mains voltage of 206 V, which is 220 V - 6.5%, or 230 V - 10.5% which is outside the EEC tolerance band and seems too low to be credible as the a.c. component.
If you’re happy to keep digging into this and upload some custom firmware, this little sketch is useful for looking at the waveform on the analog input pins directly:
#define Serial Serial3
int voltage[2000];
int current[2000];
void setup()
{
Serial.begin(115200);
Serial.println("Waveform Sampler");
analogReference(INTERNAL1V024);
analogReadResolution(12);
delay(1000);
for (int i=0; i<2000; i++) {
voltage[i] = analogRead(PIN_PD0);
current[i] = analogRead(PIN_PD5);
}
for (int i=0; i<2000; i++) {
Serial.print(voltage[i]);
Serial.print(' ');
Serial.println(current[i]);
}
}
void loop() { }
If you then plot this output, this is what you should see on the voltage input, PIN_PD0.
