EnergyMeter

Arduino library to get data from energy meters in order to monitor them.

What it is for

This library is used to monitor energy meters. It uses callbacks to trigger actions each time the meter measures a certain amount of kilowatts-hour. By using this library, energy meters can be polled (less efficient approach) or can be interfaced through external interrupts (most efficient approach).

How to install

Install the library using one of the following options

Compatibility

This library is compatible with any energy meter which is based on ADE7755 (or similar) integrated circuit. This integrated circuit has a high frequency output (CF) wich is the easiest way to interface the energy meter to a microcontroller. The most important specification of energy meters in order to monitor them with this library is impulses per kilowatt-hour.

How to use

Include the library

#include <EnergyMeter.h>

Create the Energy Meter instance

Create an instance of EnergyMeter class for each energy meter that you want to monitor, and pass the pin number and impulses per kilowatt-hour as arguments.

// Energy meter instance
EnergyMeter meter(METER_PIN, PULSES_PER_KILOWATT_HOUR);

The class constructor takes the following additional arguments:

energy : Energy measured by the meter at the moment that the instance is created. By default, zero.

voltage : Line voltage of the circuit which is power is being measured by the energy meter. You should consider that this value might change.

// EnergyMeter class's constructor signature
EnergyMeter(uint8_t pulsesPin, unsigned int pulsesPerKilowattHour, float energy = 0, float voltage = 230);

Callbacks

The library provides callbacks to trigger actions each time the meter measures a certain kind of kilowatts-hour.

// Energy measured 
meter.onConsumedEnergy(1, energyConsumed);

The callback function energyConsumed must receive a float parameter which represents the energy in kWH measured by the meter until the callback is called.

void energyConsumed(float energy)
{
  Serial.println(String(energy) + " kilowatts-hour consumed");
}

// Current consumption
meter.onCurrentChanged(currentChanged);

The callback function currentChanged will be called each time a new pulse is detected. Each time this happens, the library will calculate the current consumption

void currentChanged(float current)
{
  Serial.println(String(current) + " A consumed");
}

Polling meter

In order to continuously read the status of the meter (less efficient approach), read function must be called inside loop.

void loop() {
    meter.read();
}

Interfacing meter through external interrupts

First of all, enableInterrupt function must be called. If this function returns false, other pin should be used in order to interface the meter through external interrupts.

if (!meter.enableInterrupt(pulseDetected))
  {
    Serial.println("Pin " + String(METER_PIN) + " does not support interrupt in this board");
    while (true);
  }

When using interrupts, read method shouldn't be called inside the loop function. It should only be called in the callback provided to enableInterrupt function, as shown below:

void pulseDetected()
{
  meter.read();
}

As interruption service routines (ISR) should be as short as possible, callback functions will never be called inside the ISR. This is why update method must be continuously called inside loop. This method checks if any callback function should be called.

void loop() {
  //update() function must be called only when using interrupts.
  meter.update();
}

If there is no longer need to use external interrupts, disableInterrupt function should be called.

  meter.disableInterrupt();

Changelog

v1.0.0 (2019/08/27) - library initial release

Examples

ConsumedEnergy

Interrupt_ConsumedEnergy

winsel / EnergyMeter