implement 2 point calibration and resistance calculation

This commit is contained in:
interfisch 2023-04-20 21:52:22 +02:00
parent fc000c95ff
commit 78cc0e5c5a
1 changed files with 279 additions and 20 deletions

View File

@ -7,9 +7,6 @@
#define EC_PIN_RELAY_CALIBRATION 26 #define EC_PIN_RELAY_CALIBRATION 26
#define EC_PIN_RELAY_RANGE 25 #define EC_PIN_RELAY_RANGE 25
#define EC_CALIBRATION_RESISTOR_NC 100000
#define EC_CALIBRATION_RESISTOR_NO 1000
#define EC_PIN_ADC 4 #define EC_PIN_ADC 4
#define EC_PIN_FREQ 5 #define EC_PIN_FREQ 5
@ -17,37 +14,299 @@
#define EC_RESOLUTION 8 #define EC_RESOLUTION 8
#define EC_FREQUENCY 5000 #define EC_FREQUENCY 5000
#define EC_ARRAY_SIZE 1024 #define EC_ARRAY_SIZE 128
uint16_t ec_array[EC_ARRAY_SIZE]; uint16_t ec_array_rangeLow[EC_ARRAY_SIZE];
uint16_t ec_array_pos=0; uint16_t ec_array_rangeHigh[EC_ARRAY_SIZE];
unsigned long last_read_ec=0; uint16_t ec_array_pos=EC_ARRAY_SIZE*2;
#define EC_READ_INTERVAL 1 #define EC_MEASUREMENT_INTERVAL 10000 //complete filtered measurement every x ms
//One filtered measurement takes EC_READ_INTERVAL*EC_ARRAY_SIZE*2
#define EC_READ_INTERVAL 5 //interval of reading adc value inside a measurement
float ec_calib_rangeLow_Rlow=0; //adc value for low value resistor on low resistor value range
float ec_calib_rangeLow_Rhigh=0; //adc value for high value resistor on low resistor value range
float ec_calib_rangeHigh_Rlow=0; //adc value for low value resistor on high resistor value range
float ec_calib_rangeHigh_Rhigh=0; //adc value for high value resistor on high resistor value range
const float ec_calibresistor_low=990; //value of low value calibration resistor. Low is Relay NO
const float ec_calibresistor_high=9943; //value of high value calibration resistor. HIGH is Relay NC
unsigned long ec_last_calibration=0; //millis of last calibration
#define EC_CALIBRATION_VALID_TIME 120000 //time in ms a calibration is valid for
#define EC_RELAY_SWITCH_SETTLETIME 500 //time until voltage of ec circuit has settled
unsigned long ec_last_change_relay=0; //millis of last relay change
enum ECState{IDLE,CALIBRATELOW,CALIBRATEHIGH,MEASURE};
ECState ecstate=CALIBRATELOW;
bool ec_measurementReady();
void ec_startMeasurement();
void ec_setRange(bool);
void ec_connectProbe(bool);
void ec_setCalibration(bool calib);
void ec_releaseRelay();
void ec_startCalibration();
void ec_checkIfSettleTimeOK();
float ec_getResistance(float adc,float caliblow,float resistorlow,float calibhigh,float resistorhigh);
void ec_setup() { void ec_setup() {
pinMode(EC_PIN_ADC,INPUT); pinMode(EC_PIN_ADC,INPUT);
ledcSetup(EC_PWM_CH, EC_FREQUENCY, EC_RESOLUTION); ledcSetup(EC_PWM_CH, EC_FREQUENCY, EC_RESOLUTION);
ledcAttachPin(EC_PIN_FREQ, EC_PWM_CH); ledcAttachPin(EC_PIN_FREQ, EC_PWM_CH);
ledcWrite(EC_PWM_CH, 127); ledcWrite(EC_PWM_CH, 127); //50% duty cycle
pinMode(EC_PIN_RELAY_PROBE,OUTPUT); //LOW=Calibration/idle, HIGH=Probe connected pinMode(EC_PIN_RELAY_PROBE,OUTPUT); //LOW=Calibration/idle, HIGH=Probe connected
pinMode(EC_PIN_RELAY_CALIBRATION,OUTPUT); //LOW=NC Calibration Resistor, HIGH=NO Calib. Res. pinMode(EC_PIN_RELAY_CALIBRATION,OUTPUT); //LOW=NC Calibration Resistor, HIGH=NO Calib. Res.
pinMode(EC_PIN_RELAY_RANGE,OUTPUT); //LOW=NC Range Resistor, HIGH=NO Range Resistor pinMode(EC_PIN_RELAY_RANGE,OUTPUT); //LOW=NC Range Resistor, HIGH=NO Range Resistor
ec_releaseRelay();
ec_startCalibration();
}
void ec_loop(unsigned long loopmillis) {
static unsigned long last_measurement_ec=0;
static unsigned long last_read_ec=0;
switch (ecstate) {
case IDLE:
if (loopmillis>ec_last_calibration+EC_CALIBRATION_VALID_TIME) { //calibration needed
ec_last_calibration=loopmillis;
ecstate=CALIBRATELOW;
ec_startCalibration();
}
if (loopmillis>last_measurement_ec+EC_MEASUREMENT_INTERVAL && ecstate==IDLE) { //start measurement if idle
last_measurement_ec=loopmillis;
ec_startMeasurement();
ec_connectProbe(true);
ecstate=MEASURE;
Serial.println("EC Take Measurement");
}
break;
case CALIBRATELOW:
if (ec_measurementReady()) {
//Serial.println("EC CALIBRATELOW measurement ready");
//save measurement
ec_calib_rangeLow_Rlow=getMean(ec_array_rangeLow,EC_ARRAY_SIZE);
ec_calib_rangeHigh_Rlow=getMean(ec_array_rangeHigh,EC_ARRAY_SIZE);
//ec_checkIfSettleTimeOK();
//Switch to High calibration
ecstate=CALIBRATEHIGH;
ec_setCalibration(HIGH);
ec_setRange(LOW);
ec_startMeasurement();
//Serial.println("EC Start calibration high");
}
break;
case CALIBRATEHIGH:
if (ec_measurementReady()) {
//Serial.println("EC CALIBRATEHIGH measurement ready");
//save measurement
ec_calib_rangeLow_Rhigh=getMean(ec_array_rangeLow,EC_ARRAY_SIZE);
ec_calib_rangeHigh_Rhigh=getMean(ec_array_rangeHigh,EC_ARRAY_SIZE);
//ec_checkIfSettleTimeOK();
//Serial.println("EC Release Relay");
ec_releaseRelay();
ecstate=IDLE;
/*
Serial.println("EC Calibration done");
Serial.print("ec_calib_rangeLow_Rlow="); Serial.println(ec_calib_rangeLow_Rlow);
Serial.print("ec_calib_rangeHigh_Rlow="); Serial.println(ec_calib_rangeHigh_Rlow);
Serial.print("ec_calib_rangeLow_Rhigh="); Serial.println(ec_calib_rangeLow_Rhigh);
Serial.print("ec_calib_rangeHigh_Rhigh="); Serial.println(ec_calib_rangeHigh_Rhigh);
*/
Serial.println("EC Calibration Result: ");
Serial.print(ec_calib_rangeLow_Rlow);
Serial.print(", "); Serial.print(ec_calib_rangeHigh_Rlow);
Serial.print(", "); Serial.print(ec_calib_rangeLow_Rhigh);
Serial.print(", "); Serial.println(ec_calib_rangeHigh_Rhigh);
}
break;
case MEASURE:
if (ec_measurementReady()) {
ec_releaseRelay();
float adc_rangelow=getMean(ec_array_rangeLow,EC_ARRAY_SIZE);
float adc_rangehigh=getMean(ec_array_rangeHigh,EC_ARRAY_SIZE);
Serial.println();
float resistance_rangelow=ec_getResistance(adc_rangelow,ec_calib_rangeLow_Rlow,ec_calibresistor_low,ec_calib_rangeLow_Rhigh,ec_calibresistor_high);
Serial.print("Range Low: ADC="); Serial.print(adc_rangelow); Serial.print(", resistance="); Serial.println(resistance_rangelow);
Serial.println();
float resistance_rangehigh=ec_getResistance(adc_rangehigh,ec_calib_rangeHigh_Rlow,ec_calibresistor_low,ec_calib_rangeHigh_Rhigh,ec_calibresistor_high);
Serial.print("Range High: ADC="); Serial.print(adc_rangehigh); Serial.print(", resistance="); Serial.println(resistance_rangehigh);
ecstate=IDLE;
}
break;
}
if (loopmillis>last_read_ec+EC_READ_INTERVAL && ec_array_pos/2<EC_ARRAY_SIZE) { //take reading into array if measurement running
last_read_ec=loopmillis;
//flag_print= ec_array_pos==EC_ARRAY_SIZE;
//ec_array_pos%=EC_ARRAY_SIZE;
if (ec_array_pos<EC_ARRAY_SIZE){ //low range
ec_setRange(LOW);
}else{ //high range
ec_setRange(HIGH);
}
if (loopmillis>ec_last_change_relay+EC_RELAY_SWITCH_SETTLETIME) { //values have settled
uint16_t value=analogRead(EC_PIN_ADC);
if (ec_array_pos<EC_ARRAY_SIZE){ //low range
ec_array_rangeLow[ec_array_pos%EC_ARRAY_SIZE]=value;
}else{ //high range
ec_array_rangeHigh[ec_array_pos%EC_ARRAY_SIZE]=value;
}
/*
if (ec_array_pos==0) {
Serial.println(""); Serial.print("Lowrange:");
}
if (ec_array_pos==EC_ARRAY_SIZE) {
Serial.println(""); Serial.print("Highrange:");
}
Serial.print(value); Serial.print(" ");
if (ec_array_pos==EC_ARRAY_SIZE*2-1) {
Serial.println("");
}
*/
ec_array_pos++;
}
}
}
void ec_startCalibration() {
//Switch to Low calibration
ec_setCalibration(LOW);
ec_setRange(LOW);
ec_startMeasurement();
Serial.println("EC Started Calibration");
}
void ec_startMeasurement() {
ec_array_pos=0;
}
bool ec_measurementReady(){
if (ec_array_pos>=EC_ARRAY_SIZE*2) { //reached end of both arrays
return true;
}else{
return false;
}
}
void ec_setRange(bool range) {
//range low means low resistor value -> NO -> relay High
bool val=digitalRead(EC_PIN_RELAY_RANGE);
if (val!=!range) { //write only if different
digitalWrite(EC_PIN_RELAY_RANGE,!range);
ec_last_change_relay=millis();
}
}
void ec_connectProbe(bool relay) {
bool val=digitalRead(EC_PIN_RELAY_PROBE);
if (val!=relay) { //write only if different
digitalWrite(EC_PIN_RELAY_PROBE,relay);
ec_last_change_relay=millis();
}
}
void ec_setCalibration(bool calib) {
//calib low means low resistor value -> NO -> relay high
ec_connectProbe(false);
bool val=digitalRead(EC_PIN_RELAY_CALIBRATION);
if (val!=!calib) { //write only if different
digitalWrite(EC_PIN_RELAY_CALIBRATION,!calib);
ec_last_change_relay=millis();
}
}
void ec_releaseRelay() {
digitalWrite(EC_PIN_RELAY_PROBE,LOW); digitalWrite(EC_PIN_RELAY_PROBE,LOW);
digitalWrite(EC_PIN_RELAY_CALIBRATION,LOW); digitalWrite(EC_PIN_RELAY_CALIBRATION,LOW);
digitalWrite(EC_PIN_RELAY_RANGE,LOW); digitalWrite(EC_PIN_RELAY_RANGE,LOW);
ec_last_change_relay=millis();
} }
void ec_loop(unsigned long loopmillis, unsigned long pInterval) { void ec_checkIfSettleTimeOK() {
if (loopmillis>last_read_ec+pInterval) { /*
last_read_ec=loopmillis; Serial.print("ec_array_rangeLow[0]="); Serial.println(ec_array_rangeLow[0]);
ec_array_pos++; Serial.print("rangeLow min="); Serial.println(getMin(ec_array_rangeLow,EC_ARRAY_SIZE));
flag_print= ec_array_pos==EC_ARRAY_SIZE; Serial.print("rangeLow max="); Serial.println(getMax(ec_array_rangeLow,EC_ARRAY_SIZE));
ec_array_pos%=EC_ARRAY_SIZE; */
ec_array[ec_array_pos]=analogRead(EC_PIN_ADC); if (ec_array_rangeLow[0]<=getMin(ec_array_rangeLow,EC_ARRAY_SIZE) || ec_array_rangeLow[0]>=getMax(ec_array_rangeLow,EC_ARRAY_SIZE)){
//is first value the highest or lowest?
//Serial.print(ec_array[ec_array_pos]); Serial.print(" "); Serial.println("Warning: EC_RELAY_SWITCH_SETTLETIME might be too low! (ec_calib_rangeLow_Rlow)");
} }
/*
Serial.print("ec_array_rangeHigh[0]="); Serial.println(ec_array_rangeHigh[0]);
Serial.print("rangeHigh min="); Serial.println(getMin(ec_array_rangeHigh,EC_ARRAY_SIZE));
Serial.print("rangeHigh max="); Serial.println(getMax(ec_array_rangeHigh,EC_ARRAY_SIZE));
*/
if (ec_array_rangeHigh[0]<=getMin(ec_array_rangeHigh,EC_ARRAY_SIZE) || ec_array_rangeHigh[0]>=getMax(ec_array_rangeHigh,EC_ARRAY_SIZE)){
//is first value the highest or lowest?
Serial.println("Warning: EC_RELAY_SWITCH_SETTLETIME might be too low! (ec_array_rangeHigh)");
}
}
float ec_getResistance(float adc,float caliblow,float resistorlow,float calibhigh,float resistorhigh)
{
//adc = adc reading to calculate resistance for
//caliblow = adc value from calibration. Low resistance
//resistorlow = actual resistor value. Low resistance
//calibhjgh = adc value from calibration. High resistance
//resistorhigh = actual resistor value. High resistance
//y=mx+a;
//resistorlow=m*caliblow+a;
//resistorhigh=m*calibhigh+a;
//linear interpolation interpolate
double m=(resistorhigh-resistorlow)/(calibhigh-caliblow);
float a=resistorlow-m*caliblow;
Serial.print("m="); Serial.println(m);
Serial.print("a="); Serial.println(a);
return m*adc+a;
} }
#endif #endif