Étape 4: Logique de contrôle de température
Le code est constitué de 3 parties :
-lecture de la température du capteur et il écrit sur l’écran, on vérifie la température chaque 800ms
-boutons de lecture et d’écriture température désirée sur l’écran
-décider entre le chauffage, le refroidissement et l’état off. Nous avons inclus l’hystérésis de la température pour éviter la commutation entre les deux États souvent lorsque nous sommes près de la température désirée.
PROGRAMME :
#include <OneWire.h> #include <DallasTemperature.h> #include <LiquidCrystal.h> unsigned long lasttime; int comand; float oldTc; float Td = 21; //desired T, controlled with buttonI and buttonD float Th = 1.0; //allowed deviation float Tc; //chamber temperature int buttonD = 9; //button which decrease desired T int buttonI = 8; //button which increase desired T int relay1 = 5; int relay2 = 4; //FUNCTION WHICH READS CHAMBER TEMPERATURE #define ONE_WIRE_BUS 6 // Temperature sensors data wire is plugged into pin 6 on the Arduino. OneWire oneWire(ONE_WIRE_BUS); //Pass our oneWire reference to Dallas Temperature. DallasTemperature sensors(&oneWire); LiquidCrystal lcd(A3,A2,A1,A0,13,12); void setup(void){ lcd.begin(16, 2); delay(200); // Start up the library sensors.begin(); sensors.setWaitForConversion(false); pinMode(relay1, OUTPUT); pinMode(relay2, OUTPUT); lasttime = millis(); } void loop(void) { int button_state; if((millis()-lasttime)>800){ Tc = sensors.getTempCByIndex(0); sensors.requestTemperatures(); //Send the command to get temperatures. lasttime = millis(); } lcd.setCursor(0, 0); lcd.print("T="); lcd.print(Tc,1); lcd.print("C "); lcd.setCursor(0, 1); lcd.print("Desired T="); lcd.print(Td,1); lcd.print("C "); int down = 0; button_state=digitalRead(buttonD); if(button_state==0) { Td = Td - 0.1; down = 1; } button_state=digitalRead(buttonI); if(button_state==0) { Td = Td + 0.1; down = 1; } if (down) { //for faster/better button response delay(200); } //SELECTING BETWEEN HEATING, COOLING AND OFF if(Tc<=(Td-Th/2)){ comand = 1; } if(Tc>=(Td+Th/2)){ comand = -1; } if(Tc>Td && oldTc<=Td) { //hysteresis comand = 0; } if(Tc=Td) { //hysteresis comand = 0; } oldTc = Tc; //commands for heating, cooling and off lcd.setCursor(9, 0); if(comand==-1) { //cooling digitalWrite(4, HIGH); digitalWrite(5, LOW); lcd.print("COOLING"); } if(comand==1){ //heating digitalWrite(5, HIGH); digitalWrite(4, LOW); lcd.print("HEATING"); } if(comand==0) { //off digitalWrite(4, HIGH); digitalWrite(5, HIGH); lcd.print("OFF "); } }
