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122 lines
3.9 KiB
122 lines
3.9 KiB
// -----------------------------------------------------------------------------
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// Eergy monitor sensor
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// -----------------------------------------------------------------------------
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#pragma once
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#include "Arduino.h"
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#include "BaseSensor.h"
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#define EMON_DEBUG 0
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class EmonSensor : public BaseSensor {
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public:
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EmonSensor(double voltage, unsigned char bits, double ref, double ratio): BaseSensor() {
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// Cache
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_voltage = voltage;
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_adc_counts = 1 << bits;
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_pivot = _adc_counts >> 1;
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// Calculate factor
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_current_factor = ratio * ref / _adc_counts;
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// Calculate multiplier
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calculateMultiplier();
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#if EMON_DEBUG
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Serial.print("[EMON] Current ratio: "); Serial.println(ratio);
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Serial.print("[EMON] Ref. Voltage: "); Serial.println(ref);
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Serial.print("[EMON] ADC Counts: "); Serial.println(_adc_counts);
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Serial.print("[EMON] Current factor: "); Serial.println(_current_factor);
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Serial.print("[EMON] Multiplier: "); Serial.println(_multiplier);
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#endif
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}
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protected:
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virtual unsigned int readADC(unsigned char channel) {}
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void calculateMultiplier() {
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unsigned int s = 1;
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unsigned int i = 1;
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unsigned int m = s * i;
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while (m * _current_factor < 1) {
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_multiplier = m;
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i = (i == 1) ? 2 : (i == 2) ? 5 : 1;
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if (i == 1) s *= 10;
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m = s * i;
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}
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}
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double read(unsigned char channel) {
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int sample;
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int max = 0;
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int min = _adc_counts;
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double filtered;
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double sum = 0;
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unsigned long time_span = millis();
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for (unsigned long i=0; i<_samples; i++) {
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// Read analog value
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sample = readADC(channel);
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if (sample > max) max = sample;
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if (sample < min) min = sample;
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// Digital low pass filter extracts the VDC offset
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_pivot = (_pivot + (sample - _pivot) / EMON_FILTER_SPEED);
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filtered = sample - _pivot;
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// Root-mean-square method
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sum += (filtered * filtered);
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}
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time_span = millis() - time_span;
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// Quick fix
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if (_pivot < min || max < _pivot) {
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_pivot = (max + min) / 2.0;
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}
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// Calculate current
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double rms = _samples > 0 ? sqrt(sum / _samples) : 0;
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double current = _current_factor * rms;
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current = (double) (int(current * _multiplier) - 1) / _multiplier;
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if (current < 0) current = 0;
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#if EMON_DEBUG
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Serial.print("[EMON] Total samples: "); Serial.println(_samples);
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Serial.print("[EMON] Total time (ms): "); Serial.println(time_span);
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Serial.print("[EMON] Sample frequency (Hz): "); Serial.println(1000 * _samples / time_span);
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Serial.print("[EMON] Max value: "); Serial.println(max);
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Serial.print("[EMON] Min value: "); Serial.println(min);
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Serial.print("[EMON] Midpoint value: "); Serial.println(_pivot);
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Serial.print("[EMON] RMS value: "); Serial.println(rms);
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Serial.print("[EMON] Current: "); Serial.println(current);
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#endif
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// Check timing
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if ((time_span > EMON_MAX_TIME)
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|| ((time_span < EMON_MAX_TIME) && (_samples < EMON_MAX_SAMPLES))) {
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_samples = (_samples * EMON_MAX_TIME) / time_span;
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}
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return current;
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}
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double _voltage;
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unsigned long _adc_counts;
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unsigned int _multiplier = 1;
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double _current_factor;
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double _pivot;
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unsigned long _samples = EMON_MAX_SAMPLES;
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};
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