my problem is, if I attach the sensor to a powerline (of course only one of the three wires) which has a momentary load of 35W I got as an result 80W.
If I disconnect the wire to the sensor, it drops to 0. So the wirering itself should be ok.
If I raise the load the 80W increases too.
So, what could be wrong?
#include <SPI.h>
#include <EmonLib.h>
#define ANALOG_INPUT_SENSOR A0 // The digital input you attached your SCT sensor. (Only 2 and 3 generates interrupt!)
//#define INTERRUPT DIGITAL_INPUT_SENSOR-2 // Usually the interrupt = pin -2 (on uno/nano anyway)
EnergyMonitor emon1;
long wattsum = 0;
double kwh = 0;
double wh = 0;
long lastmillis = 0;
int minutes = 0;
void setup()
{
Serial.begin(115200);
emon1.current(ANALOG_INPUT_SENSOR, 25); // Current: input pin, calibration.
}
void loop()
{
if (millis()-lastmillis > 5000) {
double Irms = emon1.calcIrms(1480); // Calculate Irms only
if (Irms < 0.3) Irms = 0;
long watt = Irms*240.0;
wattsum = wattsum+watt;
minutes = minutes + 1;
lastmillis = millis();
Serial.print(watt); // Apparent power
Serial.print(" ");
Serial.println(Irms); // Irms
}
if (minutes == 10) {
wh = wh + wattsum/10;
kwh = wh/1000;
wattsum = 0;
minutes = 0;
}
}
What voltage does the Emon library expect at A0 with no AC current?
Measure the voltage at A0 and compare.
The code measures the AC current by measuring the DC biased AC at A0.
If the bias, the voltage when no AC is not as the library expects, that could be where your problem is.
Microcontroller: Tensilica 32-bit RISC CPU Xtensa LX106
Operating Voltage: 3.3V
Input Voltage: 7-12V<<<<---------
Digital I/O Pins (DIO): 16
Analog Input Pins (ADC): 1
UARTs: 1
SPIs: 1
I2Cs: 1
Flash Memory: 4 MB
SRAM: 64 KB
Clock Speed: 80 MHz
USB-TTL based on CP2102 is included onboard, Enabling Plug n Play
PCB Antenna
Small Sized module to fit smartly inside your IoT projects
Vin == 7V to 12V
Some loads when turned on have a surge current that can be twice or more higher than running current.
How are you measuring the AC current to calibrate your project?
I am sorry, the project is dead
the SCT 013 is not suitable for small loads. I got it working and I can do measurements with loads >500W. For example an electric heater with 1000-2000W can be monitored correctly. but even if I switch off the power, there is still be noise up to 100W which does not disappear.
So, all in all, it was a nice try but I can't use it like I want to.
I'm going to do it like my last project with a pulse counter.
And also it must be done by using an ESP32 because the library is designed for ESP32.
So my attend to do this was not correct
Hi,
Okay good to see you have what you wanted.
What power resolution does you smart power meter have, you will have to do some maths to get power as the pulse I believe represents Wh or kWh.
yeah, it's 1600 pulses for 1 kWh.
So every pulse represents 0,625 Wh.
That's ok and these cheep puls counters are relativly precise. I compared it to an other power consumption meter and the results were the same.
