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Refactor ADC handling and data storage for improved clarity and perfo…
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…rmance
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@FredM67
FredM67 committed Jan 6, 2025
1 parent 7913cfb commit 817ce38
Showing 1 changed file with 68 additions and 127 deletions.
195 changes: 68 additions & 127 deletions dev/RST_3phase_free_dev/RST_3phase_free_dev.ino
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Original file line number Diff line number Diff line change
Expand Up @@ -38,25 +38,21 @@ enum polarities
NEGATIVE,
POSITIVE
};
enum loadStates
{
LOAD_ON,
LOAD_OFF
}; // the external trigger device is active low

constexpr uint8_t ADC_TIMER_PERIOD{ 104 }; // uS (determines the sampling rate / amount of idle time)
constexpr uint8_t MAINS_CYCLES_PER_SECOND{ 50 };

constexpr uint8_t NO_OF_PHASES{ 3 }; /**< number of phases of the main supply. */

const byte outputForTrigger = 4; // active low
const byte outputForTrigger = 4; // active high

// analogue input pins
byte sensorV[NO_OF_PHASES]{ 0, 2, 4 };
byte sensorI[NO_OF_PHASES]{ 1, 3, 5 };

uint32_t cycleCount{ 0 };
uint16_t samplesRecorded{ 0 };
constexpr uint16_t DCoffsetI1_nominal{ 511 }; // nominal mid-point value of ADC @ x1 scale
constexpr uint16_t DCoffsetI_nominal{ 511 }; // nominal mid-point value of ADC @ x1 scale

int32_t DCoffset_V_long; // <--- for LPF
int32_t DCoffset_V_min; // <--- for LPF
Expand All @@ -76,8 +72,8 @@ constexpr float alpha{ 0.002 }; //
// for interaction between the main processor and the ISRs
volatile bool newCycle{ false };
volatile bool dataReady{ false };
volatile int16_t sample_I1;
volatile int16_t sample_V1;
volatile uint16_t sample_I1;
volatile uint16_t sample_V1;

enum polarities polarityOfMostRecentVsample;
enum polarities polarityOfLastVsample;
Expand All @@ -90,20 +86,21 @@ byte polarityOfLastSample_V; // for zero-crossing detection
volatile bool recordingNow{ false };
volatile bool recordingComplete{ false };
volatile byte cycleNumberBeingRecorded{ 0 };
constexpr byte noOfCyclesToBeRecorded{ 3 }; // more array space may be needed if this value is >1 !!!
constexpr byte noOfCyclesToBeRecorded{ 2 }; // more array space may be needed if this value is >1 !!!
constexpr byte noOfADCConversion{ 6 };

unsigned long recordingMayStartAt{ 0 };
bool firstLoop = true;
int settlingDelay{ 5 }; // <<--- settling time (seconds) for HPF
bool firstLoop{ true };
constexpr uint16_t settlingDelay{ 5 }; // <<--- settling time (seconds) for HPF

char blankLine[122];
char newLine[122];

constexpr uint16_t noOfSamples{ 1000000 / MAINS_CYCLES_PER_SECOND * noOfCyclesToBeRecorded / (ADC_TIMER_PERIOD * noOfADCConversion) };

int storedSample_V[210];
int storedSample_I1[210];
int storedSample_V1[noOfSamples + 10];
int storedSample_I1[noOfSamples + 10];
int storedSample_I1_from_ADC[noOfSamples + 10];

/**
* @brief Called once during startup.
Expand Down Expand Up @@ -182,104 +179,11 @@ void stopADC(void)
bit_clear(ADCSRA, ADSC);
}

void ISRProcessing()
{
static long cumVdeltasThisCycle_long{ 0 }; // for the LPF which determines DC offset (voltage)
static uint16_t sampleSetsDuringThisHalfMainsCycle{ 0 };
//

// remove DC offset from the raw voltage sample by subtracting the accurate value
// as determined by a LP filter.
const long sample_VminusDC_long = ((long)sample_V1 << 8) - DCoffset_V_long;

// determine the polarity of the latest voltage sample
if (sample_VminusDC_long > 0)
{
polarityOfMostRecentVsample = POSITIVE;
}
else
{
polarityOfMostRecentVsample = NEGATIVE;
}

if (polarityOfMostRecentVsample == POSITIVE)
{
if (polarityOfLastVsample != POSITIVE)
{
// This is the start of a new mains cycle
newCycle = true;

++cycleCount;
sampleSetsDuringThisHalfMainsCycle = 0;

} // end of specific processing for first +ve Vsample in each mains cycle

// still processing samples where the voltage is POSITIVE ...
// check to see whether the trigger device can now be reliably armed
if ((sampleSetsDuringThisHalfMainsCycle == 3) && (cycleNumberBeingRecorded == 1))
{
setPinOFF(outputForTrigger); // triac will fire at the next ZC point
}
} // end of specific processing of +ve cycles
else // the polarity of this sample is negative
{
if (polarityOfLastVsample != NEGATIVE)
{
sampleSetsDuringThisHalfMainsCycle = 0;

long previousOffset = DCoffset_V_long;
DCoffset_V_long = previousOffset + (cumVdeltasThisCycle_long >> 12);
cumVdeltasThisCycle_long = 0;

if (DCoffset_V_long < DCoffset_V_min)
{
DCoffset_V_long = DCoffset_V_min;
}
else if (DCoffset_V_long > DCoffset_V_max)
{
DCoffset_V_long = DCoffset_V_max;
}

} // end of processing that is specific to the first Vsample in each -ve half cycle
// still processing samples where the voltage is NEGATIVE ...
// check to see whether the trigger device can now be reliably armed
if ((sampleSetsDuringThisHalfMainsCycle == 3) && (cycleNumberBeingRecorded == 1))
{
setPinON(outputForTrigger); // triac will release at the next ZC point
}
} // end of processing that is specific to samples where the voltage is negative
//
// processing for EVERY set of samples
//
// extra filtering to offset the HPF effect of CT1
//
// subtract the nominal DC offset so the data stream is based around zero, as is required
// for the LPF, and left-shift for integer maths use.
long sampleI1minusDC_long = ((long)(sample_I1 - DCoffsetI1_nominal)) << 8;

long last_lpf_long = lpf_long;
lpf_long = last_lpf_long + alpha * (sampleI1minusDC_long - last_lpf_long);
sampleI1minusDC_long += (lpf_gain * lpf_long);

sample_I1 = (sampleI1minusDC_long >> 8) + DCoffsetI1_nominal;
//
if (recordingNow)
{
storedSample_V[samplesRecorded] = sample_V1;
storedSample_I1[samplesRecorded] = sample_I1;
++samplesRecorded;
}

++sampleSetsDuringThisHalfMainsCycle;
cumVdeltasThisCycle_long += sample_VminusDC_long; // for use with LP filter
polarityOfLastVsample = polarityOfMostRecentVsample; // for identification of half cycle boundaries
} // end of allGeneralProcessing()

ISR(ADC_vect)
{
static unsigned char sample_index = 0;
static int raw_sample;
static int sample_I1_raw;
static uint16_t raw_sample;
static uint16_t sample_I1_raw;

switch (sample_index)
{
Expand All @@ -291,7 +195,6 @@ ISR(ADC_vect)
sample_I1 = sample_I1_raw;

dataReady = true;
// ISRProcessing();
break;
case 1:
sample_I1_raw = ADC; // store the ADC value (this one is for current at CT1)
Expand Down Expand Up @@ -385,14 +288,22 @@ void allGeneralProcessing() // each iteration is for one set of data samples
long sample_VminusDC_long = ((long)sample_V1 << 8) - DCoffset_V_long;

// determine the polarity of the latest voltage sample
polarityOfMostRecentVsample = (sample_VminusDC_long > 0) ? POSITIVE : NEGATIVE;

if (sample_VminusDC_long > 0)
{
polarityOfMostRecentVsample = POSITIVE;
}
else
{
polarityOfMostRecentVsample = NEGATIVE;
}

if (polarityOfMostRecentVsample == POSITIVE)
{
if (polarityOfLastVsample != POSITIVE)
{
// This is the start of a new mains cycle
//togglePin(2);

++cycleCount;
sampleSetsDuringThisHalfMainsCycle = 0;

Expand All @@ -416,7 +327,7 @@ void allGeneralProcessing() // each iteration is for one set of data samples
if (timeNow > recordingMayStartAt)
{
recordingNow = true;
++cycleNumberBeingRecorded;
cycleNumberBeingRecorded++;
}
else
{
Expand All @@ -429,7 +340,7 @@ void allGeneralProcessing() // each iteration is for one set of data samples
// check to see whether the trigger device can now be reliably armed
if ((sampleSetsDuringThisHalfMainsCycle == 3) && (cycleNumberBeingRecorded == 1))
{
setPinON(outputForTrigger); // triac will fire at the next ZC point
setPinOFF(outputForTrigger); // triac will fire at the next ZC point
}
} // end of specific processing of +ve cycles
else // the polarity of this sample is negative
Expand All @@ -456,7 +367,7 @@ void allGeneralProcessing() // each iteration is for one set of data samples
// check to see whether the trigger device can now be reliably armed
if ((sampleSetsDuringThisHalfMainsCycle == 3) && (cycleNumberBeingRecorded == 1))
{
setPinOFF(outputForTrigger); // triac will release at the next ZC point
setPinON(outputForTrigger); // triac will release at the next ZC point
}
} // end of processing that is specific to samples where the voltage is negative
//
Expand All @@ -466,18 +377,25 @@ void allGeneralProcessing() // each iteration is for one set of data samples
//
// subtract the nominal DC offset so the data stream is based around zero, as is required
// for the LPF, and left-shift for integer maths use.
long sampleI1minusDC_long = ((long)(sample_I1 - DCoffsetI1_nominal)) << 8;

if (recordingNow)
{
storedSample_I1_from_ADC[samplesRecorded] = sample_I1;
}

long sampleI1minusDC_long = ((long)(sample_I1 - DCoffsetI_nominal)) << 8;

long last_lpf_long = lpf_long;
lpf_long = last_lpf_long + alpha * (sampleI1minusDC_long - last_lpf_long);
sampleI1minusDC_long += (lpf_gain * lpf_long);

sample_I1 = (sampleI1minusDC_long >> 8) + DCoffsetI1_nominal;
sample_I1 = (sampleI1minusDC_long >> 8) + DCoffsetI_nominal;
//
if (recordingNow)
{
storedSample_V[samplesRecorded] = sample_V1;
storedSample_V1[samplesRecorded] = sample_V1;
storedSample_I1[samplesRecorded] = sample_I1;
// storedSample_I1_from_ADC[samplesRecorded] = sample_I2;
++samplesRecorded;
}

Expand All @@ -496,9 +414,11 @@ void dispatch_recorded_raw_data()
for (uint16_t index = 0; index < samplesRecorded; ++index)
{
Serial.print("V: ");
Serial.print(storedSample_V[index]);
Serial.print(storedSample_V1[index]);
Serial.print(" - I1: ");
Serial.println(storedSample_I1[index]);
Serial.print(storedSample_I1[index]);
Serial.print(" - I1_from_ADC: ");
Serial.println(storedSample_I1_from_ADC[index]);
}
}

Expand All @@ -509,20 +429,23 @@ void dispatch_recorded_data()

Serial.print("cycleCount ");
Serial.print(cycleCount);
Serial.print(", samplesRecorded ");
Serial.print(", samplesRecorded ");
Serial.println(samplesRecorded);

int V, I1;
int V, I1, I1_from_ADC;
int min_V{ 1023 };
int min_I1{ 1023 };
int min_I1_from_ADC{ 1023 };
int max_V{ 0 };
int max_I1{ 0 };
int max_I1_from_ADC{ 0 };

for (uint16_t index = 0; index < samplesRecorded; ++index)
{
strcpy(newLine, blankLine);
V = storedSample_V[index];
V = storedSample_V1[index];
I1 = storedSample_I1[index];
I1_from_ADC = storedSample_I1_from_ADC[index];

if (V < min_V)
{
Expand All @@ -541,14 +464,23 @@ void dispatch_recorded_data()
max_I1 = I1;
}

newLine[map(V, 0, 1023, 0, 120)] = 'v';
if (I1_from_ADC < min_I1_from_ADC)
{
min_I1_from_ADC = I1_from_ADC;
}
if (I1_from_ADC > max_I1_from_ADC)
{
max_I1_from_ADC = I1_from_ADC;
}

newLine[map(V, 0, 1023, 0, 80)] = 'v';

int halfRange = 200;
int lowerLimit = 512 - halfRange;
int upperLimit = 512 + halfRange;
if ((I1 > lowerLimit) && (I1 < upperLimit))
{
newLine[map(I1, lowerLimit, upperLimit, 0, 120)] = '1'; // <-- raw sample scale
newLine[map(I1, lowerLimit, upperLimit, 0, 80)] = '1'; // <-- raw sample scale
}

if ((index % 2) == 0) // change this to "% 1" for full resolution
Expand All @@ -565,15 +497,22 @@ void dispatch_recorded_data()
Serial.print(min_I1);
Serial.print(", max_I1 ");
Serial.println(max_I1);
Serial.print("min_I1_from_ADC ");
Serial.print(min_I1_from_ADC);
Serial.print(", max_I1_from_ADC ");
Serial.println(max_I1_from_ADC);

Serial.println();

recordingNow = false;
firstLoop = true;

pause();
}

void pause()
{
byte done = false;
bool done = false;
byte dummyByte;

while (done != true)
Expand All @@ -582,7 +521,9 @@ void pause()
{
dummyByte = Serial.read(); // to 'consume' the incoming byte
if (dummyByte == 'g')
++done;
{
done = true;
}
}
}
}
Expand Down

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