PA fan control

VISHAY NTC 0,2-10k

NTC Thermistor VISHAY 2381 640 64103   10000 Ohm B25/85= 3977K  Kennlinie R25 = 4103 

   Rt=$C$6*EXP($G$4+$G$5/B9-$G$6/(B9*B9)-$G$7/(B9*B9*B9))

300_c_VISHAY-x_NTC 2381 640 3-4-6 Datenblatt 10k NTC-02 serie_2a.xls

107) Measuring temperature with NTC-The Steinhart-Hart Formula

//Measure NTC valuebyte NTCPin = A0;const int SERIESRESISTOR = 10000;void setup(){   Serial.begin(9600);}void loop(){        float ADCvalue; float Resistance;       ADCvalue = analogRead(NTCPin);  Serial.print("Analog value ");  Serial.print(ADCvalue); Serial.print(" = ");//convert value to resistance       Resistance = (1023 / ADCvalue) - 1;     Resistance = SERIESRESISTOR / Resistance;       Serial.print(Resistance);       Serial.println(" Ohm"); delay(1000);}//end program

//---------------byte NTCPin = A0;#define SERIESRESISTOR 10000#define NOMINAL_RESISTANCE 10000#define NOMINAL_TEMPERATURE 25#define BCOEFFICIENT 3950void setup(){Serial.begin(9600);}void loop(){float ADCvalue;float Resistance;ADCvalue = analogRead(NTCPin);Serial.print("Analog value ");Serial.print(ADCvalue);Serial.print(" = ");//convert value to resistanceResistance = (1023 / ADCvalue) - 1;Resistance = SERIESRESISTOR / Resistance;Serial.print(Resistance);Serial.println(" Ohm");float steinhart;steinhart = Resistance / NOMINAL_RESISTANCE; // (R/Ro)steinhart = log(steinhart); // ln(R/Ro)steinhart /= BCOEFFICIENT; // 1/B * ln(R/Ro)steinhart += 1.0 / (NOMINAL_TEMPERATURE + 273.15); // + (1/To)steinhart = 1.0 / steinhart; // Invertsteinhart -= 273.15; // convert to CSerial.print("Temperature ");Serial.print(steinhart);Serial.println(" oC");delay(1000);}//-------------

float sample(byte z)/* This function will read the Pin 'z' 5 times and take an average. */{   byte i; float sval = 0; for (i = 0; i < 5; i++)      {       sval = sval + analogRead(z);// sensor on analog pin 'z' }       sval = sval / 5.0;    // average        return sval;}

1) Steinhart–Hart model, using A, B, C parameters

// TPin = Analog Pin // THERMISTOR = NTC nominal value that is measured at 25*C// R1 = R Serries// A, B , C = the Steinhart–Hart coefficients, which vary depending on the type and model of thermistor and the temperature range of interest.float f_ReadTemp_ThABC(byte TPin, long THERMISTOR, float R1, float A, float B, float C) {   int Vo = analogRead(TPin);  float Resistance = (1023 / (float)Vo) - 1;                 // for pull-up configuration  float R2 = R1 / Resistance;    float logR2 = log(R2);                             // Pre-Calcul for Log(R2)  float T = (1.0 / (A + B*logR2 + C*logR2*logR2*logR2));   T =  T - 273.15;                                    // convert Kelvin to *C  return T;}

// TPin = Analog Pin // THERMISTOR = NTC nominal value that is measured at 25*C// R1 = R Serries// BETA = the coefficient of the thermistor (3950 is a common value).// TEMPNOMINAL = usual is 25 (*C)float f_ReadTemp_Th(byte TPin, long THERMISTOR, float R1, float BETA, int TEMPNOMINAL) {    int Vo = analogRead(TPin);  float Resistance = (1023 / (float)Vo) - 1;   // for pull-up configuration  float R2 = R1 / Resistance;    float steinhart;  steinhart = R2 / THERMISTOR;                     // (R/Ro)  steinhart = log(steinhart);                          // ln(R/Ro)  steinhart /= BETA;                                 // 1/B * ln(R/Ro)  steinhart += 1.0 / (TEMPNOMINAL + 273.15);   // + (1/To)  steinhart = 1.0 / steinhart;                       // Invert  steinhart -= 273.15;                         // convert Kelvin to *C  return steinhart;}

/*  Thermistor based temperature sensor.  10k NTC Thermistor:    SparkFun SEN-00250    Mouser P/N 474-SEN-00250    Vishay part #: NTCLE100E3103JB0   Circuit:    10.09 k resistor  (10,090 ohms)  *///////////////////////////////////////////////////////////////////////////////// TimerA// 10000000 us = 10000 ms = 10 sec = 0.1 Hz // 1000000 us = 1000 ms = 1 sec = 1 Hz// 100000 us = 100 ms = 0.1 sec = 10 Hz// 10000 us = 10 ms = 0.01 sec = 100 Hz// 1000 us = 1 ms = 0.001 sec = 1 kHz// 100 us = 0.1 ms = 0.0001 sec = 10 kHzconst unsigned long timerA = 2000;  unsigned long timerAlap = millis();  // timer/////////////////////////////////////////////////////////////////////////const byte pinBuiltInLED = 13;/////////////////////////////////////////////////////////////////////////// Global variables for blinkLEDnoDelay()unsigned long LEDblinkPeriod = 8;unsigned long LEDblinkLast = 0;byte LEDblinkPWM = 0;bool LEDblinkState = false;byte LEDlastMode = 0;void blinkLEDnoDelay(byte pin, byte mode);/////////////////////////////////////////////////////////////////////////// 10k NTC Thermistor  NTCLE100E3103JB0byte pinThermister = A0;float R1 = 10090.0;   // 10,090 ohm resister in Thermister voltage divider circuit.void setup () {  pinMode(pinBuiltInLED, OUTPUT);  delay(1);  pinMode(pinThermister, INPUT);  delay(1);  //  DEFAULT: analog reference of 5 volts on 5V Arduino boards   analogReference(DEFAULT);  delay(1);  Serial.begin(9600);  while (!Serial) {    digitalWrite(pinBuiltInLED, HIGH);    delay(1);    digitalWrite(pinBuiltInLED, LOW);  }  Serial.println("\nSerial ready");  timerAlap = millis(); // reset the timer} // setup()void loop() {  //  Timer A  if (timerAlap > millis())  timerAlap = millis();  if (millis() - timerAlap > timerA) {     digitalWrite(pinBuiltInLED, HIGH);    // Take a reading    float dTempF = GetThermisterTempF(pinThermister);    Serial.print("Temperature: ");     Serial.print(dTempF);    Serial.println(" F");     digitalWrite(pinBuiltInLED, LOW);    timerAlap = millis(); // reset the timer  }  } // loop()////////////////////////////////////////////////////////////////float GetThermisterTempF(byte pinADC) {  // Read the 10k NTC Thermistor and return the temperature in F.     //  10k NTC Thermistor:  //    SparkFun SEN-00250  //    Mouser P/N 474-SEN-00250  //    Vishay part #: NTCLE100E3103JB0     int iADC = analogRead(pinADC);  // ADC constants below used for ADC conversion to mV  // 10 bit, 0 to 1023, or 1024 steps  (Arduino)  // 12 bit, 0 to 4095, or 4096 steps  const float FSadc = 1024.0;    // FSmV is the full scale value in mV for the analog input at pinADC.  // (it is NOT the voltage input to the voltage divider).  // Use 5000.0 mV for 5 V (Arduino), use 3300 mV for 3.3 V microcontrollers.  const float FSmV = 5000.0;  // Calculate the voltage measured at pin ADC.  float mV = iADC*(FSmV/FSadc);  // Calculate the circuit resistance from the measured mV (at pinADC)  // using the voltage divider circuit formula:  //   Vout = Vin * (R2 / (R1 + R2))  //   R2 = R1 * (Vin/Vout - 1)  // Assign to Vin the voltage going into the thermistor voltage divider  // circuit. Typically this would be the same as FSmV.   float Vin = 5000.0;     float R2 = R1 * (Vin / mV - 1.0);    // Convert resistance to temperature using Steinhart–Hart equation  // a1,b1,c1,d1 and equation from Vishay datasheet   float a1=3.354016E-3, b1=2.569850E-4, c1=2.620131E-6, d1=6.383091E-8;  float Rref = 10000.0;   // This is a 10 k thermister  float T = 1/(a1+b1*log(R2/Rref)+c1*log(R2/Rref)+d1*log(R2/Rref));  // T is in degrees Kelvin  T = T - 273.15; // degrees C  T = (T * 9.0)/ 5.0 + 32.0;    // degrees F  return T;} // GetThermisterTempF()

Steinhart-Thermistor (community library)

Steinhart-Thermistor v2

4 coefficients Steinhart version of Thermistor library.

1/T = A + Blog(R/Rt) + Clog(R/Rt)^2 + D**log(R/Rt)^3

In the standard Steinhart-Hart equation the C parameter is set to zero.However, some manufacturers use all 4 coefficients.

Typical usage

Connect a Thermistor to an Analog pin and use the library to get the temperature.

#include "Steinhart-Thermistor.h"Thermistor Thermistor(A0);void setup() {Serial.begin(9600);}void loop() {//Always call calcResistance() first.//It's the only function that read the ADC value.//Otherwise you could get a different value for each temperature unit.//You can specify a number of samples. Default = 1.Thermistor.calcResistance();Serial.print("Thermistor resistance: ");Serial.println(Thermistor.getResistance());Serial.print("Volts: ");Serial.println(Thermistor.getVolts());Serial.print("Analog value at pin: ");Serial.println(Thermistor.getAval());Serial.print("Kelvin: ");Serial.println(Thermistor.getTempK());Serial.print("Celsius: ");Serial.println(Thermistor.getTempC());Serial.print("Fahrenheit: ");Serial.println(Thermistor.getTempF());delay(1000);}

109) Completely Integrated, 0.1°C Thermistor Measurement System Using a Low Power, Precision, 24-Bit Sigma-Delta ADC

110) elektor Differenz-Temperaturindikator

Temperatursensoren und Thermistoren (PTC, NTC, STS, PT1000, u.a.)

Schnelle Erstellung einer exakten Temperaturmessschaltung auf Thermistorbasis

SchaltungsdesignTemperaturmesssystem mit Thermistoren oder RTD?

Temperaturmesssystem mit Thermistoren designen