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Merge pull request #13703 from ascillato/patch-1 

Fix NTC Temp calc for ESP32
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Theo Arends 2021-11-17 09:16:59 +01:00 committed by GitHub
parent 2b7b314488 7f8ca14770
commit b6b14887ae
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1 changed files with 9 additions and 2 deletions
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11
tasmota/xsns_02_analog.ino
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@ -43,7 +43,7 @@
// Parameters for equation
#define ANALOG_V33 3.3 // ESP8266 / ESP32 Analog voltage
#define ANALOG_T0 TO_KELVIN(25.0) // 25 degrees Celcius in Kelvin (= 298.15)
#define ANALOG_T0 TO_KELVIN(25.0) // 25 degrees Celsius in Kelvin (= 298.15)
// Shelly 2.5 NTC Thermistor
// 3V3 --- ANALOG_NTC_BRIDGE_RESISTANCE ---v--- NTC --- Gnd
@ -409,8 +409,15 @@ void AdcEverySecond(void) {
for (uint32_t idx = 0; idx < Adcs.present; idx++) {
if (ADC_TEMP == Adc[idx].type) {
int adc = AdcRead(Adc[idx].pin, 2);
// Steinhart-Hart equation for thermistor as temperature sensor
// Steinhart-Hart equation for thermistor as temperature sensor:
// double Rt = (adc * Adc[idx].param1 * MAX_ADC_V) / (ANALOG_RANGE * ANALOG_V33 - (double)adc * MAX_ADC_V);
// MAX_ADC_V in ESP8266 is 1
// MAX_ADC_V in ESP32 is 3.3
#ifdef ESP8266
double Rt = (adc * Adc[idx].param1) / (ANALOG_RANGE * ANALOG_V33 - (double)adc); // Shelly param1 = 32000 (ANALOG_NTC_BRIDGE_RESISTANCE)
#else
double Rt = (adc * Adc[idx].param1) / (ANALOG_RANGE - (double)adc);
#endif
double BC = (double)Adc[idx].param3 / 10000; // Shelly param3 = 3350 (ANALOG_NTC_B_COEFFICIENT)
double T = BC / (BC / ANALOG_T0 + TaylorLog(Rt / (double)Adc[idx].param2)); // Shelly param2 = 10000 (ANALOG_NTC_RESISTANCE)
Adc[idx].temperature = ConvertTemp(TO_CELSIUS(T));