I have 3 different sensors all the same as listed above. I have tried all three with the same results.
Just for the hell of it I hooked up the old Arduino to the circuit and it is reading the amperage correctly on all three sensors.
This is the Arduino code it is C# as well.
int mVperAmp = 40;
int ACSoffset = 2500;
int RawValue= 0;
double Voltage = 0;
double Amps = 0;
RawValue = analogRead(analogIn);
Voltage = (RawValue / 1023.0) * 5000; // Gets you mV
Amps = ((Voltage - ACSoffset) / mVperAmp);
The only difference is that with the Arduino I have to manually code the sample rate since there is no built in way of doing it. Without doing this the amp output would be Positive or Negative depending when it grabbed the reading since AC current is a sine wave as well as it may or may not be the actual amperage depending on where it was at in the wave.
So the only difference is the Raspberry Pi and the ADC Pi Plus. If the Pi would have an analog input this may have been easier.
Maybe it’s a Pi thing or an ADC Pi Plus thing I don’t know.
I read Here: https://www.abelectronics.co.uk/forums/thread/adc-strange-behaviour
that is could be a mode issue. Could that be?