File content as of revision 2:7f6a39ec5c01:

#include "PowerMeasurement.h"


//#define DEBUG "POWR"
// ...
// INFO("Stuff to show %d", var); // new-line is automatically appended
//
#if (defined(DEBUG) && !defined(TARGET_LPC11U24))
#define INFO(x, ...) std::printf("[INF %s %4d] "x"\r\n", DEBUG, __LINE__, ##__VA_ARGS__);
#define WARN(x, ...) std::printf("[WRN %s %4d] "x"\r\n", DEBUG, __LINE__, ##__VA_ARGS__);
#define ERR(x, ...)  std::printf("[ERR %s %4d] "x"\r\n", DEBUG, __LINE__, ##__VA_ARGS__);
static void HexDump(const char * title, const uint8_t * p, int count)
{
    int i;
    char buf[100] = "0000: ";

    if (*title)
        INFO("%s", title);
    for (i=0; i<count; ) {
        sprintf(buf + strlen(buf), "%02X ", *(p+i));
        if ((++i & 0x0F) == 0x00) {
            INFO("%s", buf);
            if (i < count)
                sprintf(buf, "%04X: ", i);
            else
                buf[0] = '\0';
        }
    }
    if (strlen(buf))
        INFO("%s", buf);
}
#else
#define INFO(x, ...)
#define WARN(x, ...)
#define ERR(x, ...)
#define HexDump(a, b, c)
#endif

DigitalOut mip(LED1);
DigitalOut sam(LED2);

PowerMeasurement::PowerMeasurement(AnalogIn * _AinList, BusOut * _MuxBus, DigitalOut * _Select, 
    GetVoltage_T _GetVoltage, int _AinCount, int _MuxChannels) {
    if (_AinList)
        AinList = _AinList;
    if (_MuxBus)
        MuxBus = _MuxBus;
    if (_Select) {
        Select = _Select;
    }
    GetVoltage = &_GetVoltage;
    AinCount = _AinCount;
    NumMuxes = _AinCount;
    MuxChannels = _MuxChannels;
    
    totalChannels = (NumMuxes > 0) ? AinCount * (NumMuxes * MuxChannels) : AinCount;
    fullScaleCurrent = (float *)malloc(totalChannels * sizeof(float));
    for (int i=0; i<totalChannels; i++) {
        fullScaleCurrent[i] = 1.0f;
    }
    fullScaleVoltage = 1.0f;

    if (AinCount > 0 && AinCount <= 6) {
        //INFO("Configure for %d A/D inputs", AinCount);
    }

    rawSamples = (RawPowerData_T *)malloc(SAMPLES_PER_CYCLE * CYCLES_PER_SAMPLE * sizeof(RawPowerData_T));
    sampleNum = 0;
    
    frequency(60.0f);          // default is pathetically slow, but good for basic testing...
    
    inProcess = false;
    isComplete = false;
}


/// The destructor.
PowerMeasurement::~PowerMeasurement() {
    free(fullScaleCurrent);
}


/// Defines the overall frequency of the line voltage.
///
/// Based on this line frequency, the sample-rate for the measurement is set.
/// 
/// @param[in] Hz sets the line frequency.
///
void PowerMeasurement::frequency(float _Hz) {
    uSecInterval = 1.0e6 / _Hz / SAMPLES_PER_CYCLE;
}


/// Defines the measuremenbt interval.
///
/// Instead of defining the measurement interval by line frequency, the period
/// can be directly set.
///
/// @param uSec is the number of microseconds between samples.
/// 
void PowerMeasurement::period_us(uint32_t uSec) {
    uSecInterval = uSec;
}


/// Set the voltage to current calibration value for a channel.
///
/// Each analog input channel can be configured for the current sensor used on that channel.
/// If the channel has a 30 A current sensor, that channel should be set to 30.0f.
/// If the user calibrates the sensor more precisely, an improved calibration factor (e.g. 31.1)
/// can be defined.
///
/// @param[in] channel defines the channel to calibrate.
/// @param[in] fullScaleCurrent is the calibration factor representing the full-scale current.
/// @returns true if the value is accepted.
/// @returns false if the channel was incorrect.
///
bool PowerMeasurement::SetFullScaleCurrent(int channel, float fullScaleCurrentCalibration) {
    if (channel >= 0 && channel < totalChannels) {
        fullScaleCurrent[channel] = fullScaleCurrentCalibration;
        return true;
    } else {
        return false;
    }
}


/// Set the voltage value representing the full scale measurement.
///
/// The GetVoltage callback is based on a uint16_t. This API sets the full scale voltage
/// representing the value FFFF. Based on an A/C input, biased to the split supply, this
/// represents an A/D value of 7FFF. When configured for a 120V circuit, which measures
/// approximately 170v peak, the fullScaleVoltage value would be 170.0f.
/// 
/// @param[in] fullScaleVoltage is the full-scale voltage value.
/// @returns true if the value is accepted.
/// 
bool PowerMeasurement::SetFullScaleVoltage(float fullScaleVoltageCalibration) {
    fullScaleVoltage = fullScaleVoltageCalibration;
    return true;
}


/// Starts a measurement on the specified channel.
///
/// This starts the measurement on a specified channel.
///
/// @param[in] channel defines the channel to measure. This is in the range of 0 to N-1, where N is 
///         AinCount * MuxChannels.
/// @returns true if the measurement can be started.
/// @returns false if the measurement cannot be started - likely because of an incorrect channel 
///         selection.
///
bool PowerMeasurement::StartMeasurement(int channel) {
    if (channel >= 0 && channel < totalChannels) {
        int muxCh;
        
        inProcess = true;
        isComplete = false;
        sampleNum = 0;      // ready for the first sample
        if (NumMuxes > 0) {
            muxCh           = channel % MuxChannels;
            a2dChannel      = channel / MuxChannels;
            *MuxBus         = muxCh;
            Select->write(false);
        } else {
            a2dChannel = channel;
        }
        INFO("StartMeasurement(%2d) at %d usec, Mux Ch: %d, A/D ch: %d",
            channel, uSecInterval, (NumMuxes) ? muxCh : 0, a2dChannel);
        #if 1
        // Directly calling the TakeSample works, but StartMeasurement is then is a blocking call
        while (inProcess) {
            TakeSample();
            wait_us(uSecInterval);  // this now has 'slippage' in time, based on TakeSample execution
        }
        mip = false;
        #else
        // Attaching it to a timer seems not to work, for reasons not yet understood
        sampleTimer.attach_us(this, &PowerMeasurement::TakeSample, uSecInterval);
        mip = true;
        #endif
        return true;
    } else {
        ERR("Cannot StartMeasurement(%d) of %d", channel, totalChannels);
        mip = false;
        return false;
    }
}

void PowerMeasurement::TakeSample(void) {
    rawSamples[sampleNum].current = AinList[a2dChannel].read_u16();
    if (GetVoltage)
        rawSamples[sampleNum].voltage = (*GetVoltage)();
    else
        rawSamples[sampleNum].voltage = 0 + 32768;          // bias to mid-point
    sampleNum++;
    sam = !sam;
    if (sampleNum > (SAMPLES_PER_CYCLE * CYCLES_PER_SAMPLE)) {
        inProcess = false;
        isComplete = true;
        mip = false;
    }
}

/// Determines if the conversion is complete and the results are readable.
///
/// @returns true if the measurement is complete (or if no measurement is in process).
/// @returns false if the measurement is in process.
///
bool PowerMeasurement::readable() {
    return isComplete;
}


/// Get the real power measurement.
///
/// This retrieves the real power measurement for the channel which just completed measurement.
/// This is the average of the instantaneous power.
///
/// @returns the real power measurement.
///
float PowerMeasurement::GetRealPower() {
    if (isComplete) {
        float sumInstantP = 0.0f;

        for (int i=0; i<(SAMPLES_PER_CYCLE * CYCLES_PER_SAMPLE); i++) {
            float voltage = fullScaleVoltage * ((float)rawSamples[i].voltage - PM_ZERO_OFFSET) / PM_FULL_SCALE;
            float current = fullScaleCurrent[a2dChannel] * ((float)rawSamples[i].current - PM_ZERO_OFFSET) / PM_FULL_SCALE;
            
            sumInstantP += (voltage * current);
        }
        float realP = sumInstantP / (SAMPLES_PER_CYCLE * CYCLES_PER_SAMPLE);
        return realP;
    } else {
        return 0.0f;
    }
}


/// Get the rms voltage measurement.
///
/// This retrieves the rms voltage measurement for the channel which just completed measurement.
///
/// @returns the rms voltage measurement.
///
float PowerMeasurement::GetRMSVoltage() {
    if (isComplete) {
        float sumSquaredV = 0.0f;

        for (int i=0; i<(SAMPLES_PER_CYCLE * CYCLES_PER_SAMPLE); i++) {
            float voltage = fullScaleVoltage * ((float)rawSamples[i].voltage - PM_ZERO_OFFSET) / PM_FULL_SCALE;
            
            sumSquaredV += (voltage * voltage);
        }
        float rmsV = sqrt(sumSquaredV / (SAMPLES_PER_CYCLE * CYCLES_PER_SAMPLE));
        return rmsV;
    } else {
        return 0.0f;
    }
}


/// Get the rms current measurement.
///
/// This retrieves the rms current measurement for the channel which just completed measurement.
///
/// @returns the rm current measurement.
///
float PowerMeasurement::GetRMSCurrent() {
    if (isComplete) {
        float sumSquaredCurrent = 0.0f;

        for (int i=0; i<(SAMPLES_PER_CYCLE * CYCLES_PER_SAMPLE); i++) {
            float current = fullScaleCurrent[a2dChannel] * ((float)rawSamples[i].current - PM_ZERO_OFFSET) / PM_FULL_SCALE;
            
            sumSquaredCurrent += (current * current);
        }
        float meanSqC = sumSquaredCurrent / (SAMPLES_PER_CYCLE * CYCLES_PER_SAMPLE);
        return sqrt(meanSqC);
    } else {
        return 0.0f;
    }
}


bool PowerMeasurement::GetPeakCurrent(float * negPeak, float * posPeak)
{
    if (isComplete) {
        for (int i=0; i<(SAMPLES_PER_CYCLE * CYCLES_PER_SAMPLE); i++) {
            if (i == 0) {
                if (negPeak)
                    *negPeak = fullScaleCurrent[a2dChannel] * ((float)rawSamples[i].current - PM_ZERO_OFFSET) / PM_FULL_SCALE;
                if (posPeak)
                    *posPeak = fullScaleCurrent[a2dChannel] * ((float)rawSamples[i].current - PM_ZERO_OFFSET) / PM_FULL_SCALE;
            } else {
                float testVal = fullScaleCurrent[a2dChannel] * ((float)rawSamples[i].current - PM_ZERO_OFFSET) / PM_FULL_SCALE;
                if (negPeak && testVal < *negPeak)
                    *negPeak = testVal;
                if (posPeak && testVal > *posPeak)
                    *posPeak = testVal;
            }
        }
        return true;
    } else {
        return false;
    }    
}


/// Get the apparent power measurement.
///
/// This retrieves the apparent power measurement for the channel which just completed measurement.
///
/// @returns the apparent power measurement.
///
float PowerMeasurement::GetApparentPower() {
    if (isComplete) {
        return GetRMSVoltage() * GetRMSCurrent();
    } else {
        return 0.0f;
    }
}


float PowerMeasurement::GetPowerFactor() {
    if (isComplete) {
        return GetRealPower() / GetApparentPower();
    } else {
        return 0.0f;
    }
}


bool PowerMeasurement::GetRawSample(int sample, RawPowerData_T * rawsample) {
    if ((isComplete || (inProcess && sampleNum > sample)) && sample >= 0) {
        if (rawsample)
            *rawsample = rawSamples[sample];
        return true;
    } else {
        return false;
    }
}

int PowerMeasurement::GetRawSampleCount(void) {
    return SAMPLES_PER_CYCLE * CYCLES_PER_SAMPLE;
}