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????????????????????????????????? ?????? Arduino ?????????
![const int relayPin = X;
const int onPeriod[] = {0,1,1,2,2,3,6,7,8,9,10};
const int offPeriod[] = {5,9,5,4,5,3,4,3,2,1,0};
void heaterOn(int duty_cycle) {
if (duty_cycle > 0) {
idx = duty_cycle/10; // lookup table step 10%
if (onPeriod[idx] > 0) {
digitalWrite(relayPin, HIGH);
delay(onPeriod[idx]*1000);
}
if (offPeriod[idx] > 0) {
digitalWrite(relayPin, LOW);
delay(offPeriod[idx]*1000);
}
} else {
delay(10000);
}
}](https://image.slidesharecdn.com/tupineproject-tempctrler-150510083113-lva1-app6891/85/-9-320.jpg)
?????????????????
- 1. Temperature controller ? ??? ????? ¨C ?????????????????????????????????????? ¨C ??????????????????????????????? AC relay DS18b20 (~150oC) Thermocouple (~750oC)
- 2. Relay module ? ????? ETT-OPTO RELAY4 ?????????? AC ????? 4 ???? http://www.ett.co.th/download2.html
- 3. ETT OPTO-RELAY4 ? ??? relay ??????????????? ????? normally open
- 4. DS18B20 sensor ? ???????????? 1-wire ????????????????? http://datasheets.maximintegrated.com/en/ds/DS18B20.pdf ? ?????? Arduino ??????????????? DS18B20 http://playground.arduino.cc/Learning/OneWire http://www.pjrc.com/teensy/td_libs_OneWire.html
- 5. Thermocouple shield ? ??????????????????????????? Seebeck ???????????????? ?????????????????????? ? (???? mV) ¨C ?????????????????????????? (offset) ????????????? (amplify) ? ??? thermocouple shield ?????????????? https://oceancontrols.com.au/KTA-259.html
- 6. Procedure ? ???????? Arduino ??????????????????????? ¨C ????????????????????????????????????? serial monitor ¨C ???????????????/????? ?????????????????? 1 ?????? ¨C ???????????????? ????????????????????????????????? (Smax) ¨C ??????????????????? (Tmax) ? ???????? Arduino ????????????????????????????????????? ¨C ???????????????????? ?T = Tmax / 100 ¨C ???????????????????? = 0.1 * ?T/Smax (??????????? 1 ?????? ?????????? 1 ??????) ¨C ???????????/??????? pulse-width modulation
- 7. #define STEP (X) const int onPeriod = Y; const int offPeriod = Z; void setup() { initTempSensor(); initRelayBoard(); Serial.begin(9600); } void loop() { float temp = readTempSensor(); Serial.print("Temp: "); Serial.println(temp); delay(X*Y); onRelay(); delay(X*Z); offRelay(); } ????????????????????????????? ???????????? ????? msec
- 8. ?????? burst firing ? ???????????? PWM ????????????? AC ????????????? triac ????????????? zero-crossing ?????????????????? ¨C ????????? burst firing ??????? AC power ????????????????????????? ¨C ??? cycle time ???????????????????? ???? ?????????????????????????????????
- 9. const int relayPin = X; const int onPeriod[] = {0,1,1,2,2,3,6,7,8,9,10}; const int offPeriod[] = {5,9,5,4,5,3,4,3,2,1,0}; void heaterOn(int duty_cycle) { if (duty_cycle > 0) { idx = duty_cycle/10; // lookup table step 10% if (onPeriod[idx] > 0) { digitalWrite(relayPin, HIGH); delay(onPeriod[idx]*1000); } if (offPeriod[idx] > 0) { digitalWrite(relayPin, LOW); delay(offPeriod[idx]*1000); } } else { delay(10000); } }
- 10. PID controller ? ????????????? = ???????????????????????????? error = setpoint - feedback ? setpoint ?????????? potentiometer ? Feedback ???????????????????
- 11. #define MAX_TEMP (X.Y) const float Kp = 1.0; const float Ki = 0.0; const float Kd = 0.0; float sumErr = 0.0; float lastTemp = 0.0; setpoint = (analogRead(0)/5.0) * 100; temp = readTempSensor()/MAX_TEMP * 100; float pidCtrl(float setpoint, float temp) { float error, ctrl, tempChange; error = setpoint ¨C temp; sumErr += error; tempChange = speed ¨C lastTemp; ctrl = Kp*error + Ki*sumErr + Kd*tempChange; lastTemp = temp; return ctrl; } ??????????????????????????? PID ???????????? ??? pot ????? A0
- 12. const int PERIOD (X); int ratioPWM(float ctrl) { int onPeriod = (PERIOD*STEP) * (ctrl/100); if (onPeriod > 0) { onRelay(); delay(onPeriod); offRelay(); delay(PERIOD*STEP - onPeriod); } else { offRelay(); delay(PERIOD*STEP); } } ??????????????????????????? PID ????????
- 13. Results ? ????????????? (?????? 3-4 ???? ?????????????) ¨C ?????????????????????????????????????????????????? ¨C ???????????????????????????????????????????? PWM ?????????? ??? ???????????????????????? ON/OFF ???????? ¨C ?????????????????????????????? PID ????????? PERIOD = 10, 15, 20, 25 ¨C ????????????????????????????????????????????? potentiometer ? ????????????????????????????????????????????? ¨C ??????????????????????? ?????????????? 220Vrms ??????????? ?????