RTA-Temperature-Controller.ino

/*
  QDEV UBC, 2021
  Ray: raysu@student.ubc.ca; github @ sillyPhotons
  Anton: antoncecic3@gmail.com

  Timer Interrupt Code From: https://www.techtonions.com/6-simple-ways-to-blink-arduino-led/
*/

#include <SPI.h>
#include <Wire.h>


// libraries that likely need to be downloaded in library manager
#include <PID_v1.h>
#include <SparkFunMAX31855k.h>
#include <Adafruit_SSD1306.h>

// additional libraries included with the file
#include "StackArray/StackArray.h"
#include "src/HeatingStep.h"

#define SSR_PIN 5         // PWM pin that activates the relay
#define START_PIN 23      // Pin that is hooked up to the START button

uint8_t START = LOW;

SparkFunMAX31855k probe(8);
Adafruit_SSD1306 display(128, 64, &Wire, -1);

// Ruiheng: I ripped this from our FastDAC code!
typedef struct PIDparam
{
  bool forward_dir = true;
  double Input = 0.0;
  double Output = 0.0;
  double Setpoint = 0.0;
  double kp = 0.1;
  double ki = 1.0;
  double kd = 0.0;
} PIDparam;

PIDparam g_pidparam[1];

PID myPID(&(g_pidparam[0].Input),
          &(g_pidparam[0].Output),
          &(g_pidparam[0].Setpoint),
          g_pidparam[0].kp,
          g_pidparam[0].ki,
          g_pidparam[0].kd,
          P_ON_M,
          DIRECT);

double _T;  // This gets read directly
double T;  // This only updates if _T is not a NaN

unsigned long START_TIME;
unsigned long LastSerialSend = 0;

// --------------------------------------------------------------------------------
// Temperature [C], kP, kI, kD, Seconds to Hold Temperature At, delta_t
// delta_t == Use MAX power until within delta_t of target temperature

//String sequence_name = "Diana's seq.";
//HeatingStep step0(355, 20, 20, 3, 2*60*60, 10.0);
//HeatingStep step1(50, 0.0, 0.0, 0.0, 1, 0);

// Johann's Sequence
// Set knob to 70% full power
//// 5mBar Forming Gas
//String sequence_name = "Johann's seq..";
//HeatingStep step0(435, 20, 20, 5.0, 60, 5.0); 
//HeatingStep step1(50, 0.0, 0.0, 0.0, 1, 0);
//HeatingStep step0(120/\, 20, 20, 5.0, 60*5, 5.0);
//HeatingStep step1(50,0.0, 0.0, 1, 0);
//HeatingStep step4(435, 2, 0, 0.0,  0.0, 60, 15.0);
//HeatingStep step5(300, 0.0, 0.0, 0.0, 1, 0);

//HeatingStep step0(450, 5, 5, 0.0, 60, 15.0);
//HeatingStep step1(300, 0.0, 0.0, 0.0, 1, 0);
//HeatingStep step2(450, 5, 3, 0.0, 60, 15.0);
//HeatingStep step3(300, 0.0, 0.0, 0.0, 1, 0);
//HeatingStep step4(450, 5, 1, 0.0, 60, 15.0);
//HeatingStep step5(300, 0.0, 0.0, 0.0, 1, 0);

// Lily's Sequence
// it is actually from pierre
// 70% power, 5mbar
//String sequence_name = "Lily's seq.";
//HeatingStep step0(120, 17, 17, 8, 60, 10.0); //overshooting to 150 is ok 
//HeatingStep step1(370, 20, 20, 5.0, 5, 5.0);
//HeatingStep step2(440, 20, 20, 5.0, 70, 5.0); //uncommented steps so now it should get there
//HeatingStep step3(50, 0.0, 0.0, 0.0, 1, 0);

// Vahid's Sequence
// it's from what Lily did with the Wafer 4-5-21.1 Chip number 12(X), found on her notebook (04-26-2023 RT Testing X)
//70% power, 5mbar
String sequence_name = "Vahid's seq.";
HeatingStep step0(120, 17, 17, 8, 60, 10.0); //overshooting to 150 is ok 
HeatingStep step1(370, 20, 20, 5.0, 5, 5.0);
HeatingStep step2(435, 20, 20, 5.0, 80, 5.0); //uncommented steps so now it should get there
HeatingStep step3(50, 0.0, 0.0, 0.0, 1, 0);

// Ebrahim's Sequence
// Set knob to 60% full power
//String sequence_name = "Ebramhim's seq.";
//HeatingStep step0(300, 4.00, 1.2, 0.0, 3600, 6.0);
//HeatingStep step1(50, 0.0, 0.0, 0.0, 1, 0);

// Ray's Sequence
//String sequence_name = "Rays's seq.";
//HeatingStep step0(330, 4.00, 1.2, 0.0, 120, 6.0); // changed delta_t
//HeatingStep step1(445, 3.8, 0.9, 0.0, 120, 5.0);  // changed delta_t from 3 to 5
//HeatingStep step2(50, 0.0, 0.0, 0.0, 1, 0);

//HeatingStep step0(330, 2.00, 1.2, 0.0, 120, 6.0); // changed delta_t
//HeatingStep step1(445, 3.8, 0.9, 0.0, 120, 5.0);  // changed delta_t from 3 to 5
//HeatingStep step2(50, 0.0, 0.0, 0.0, 1, 0);

// Anton's Sequence
//String sequence_name = "Anton's seq.";
//HeatingStep step0(400, 7.00, 1.2, 1.0, 60*60*5, 5.0); // changed delta_t
//HeatingStep step1(50, 0.0, 0.0, 0.0, 1, 0);
//
//String sequence_name = "Anton 2";          // power = 50%, 5mbar gas
//HeatingStep step0(300, 20, 1.5, 1, 60*60*4, 1.0); 
//HeatingStep step1(50, 0.0, 0.0, 0.0, 1, 0);

//String sequence_name = "Mukhlasur 350";          // power = 30%, vaccuum, no gas
//HeatingStep step0(350, 20, 2, 1, 60*90, 1.0); 
//HeatingStep step1(50, 0.0, 0.0, 0.0, 1, 0);

//String sequence_name = "Mukhlasur 400";          // power = 30%, vaccuum, no gas
//HeatingStep step0(400, 20, 1, 1, 60*90, 1.0); 
//HeatingStep step1(50, 0.0, 0.0, 0.0, 1, 0);

//String sequence_name = "Mukhlasur 450";          // power = 34%, vaccuum, no gas
//HeatingStep step0(450, 20, 1.5, 1, 60*90, 1.0); 
//HeatingStep step1(50, 0.0, 0.0, 0.0, 1, 0);

// 300 C 5 mbar anneal for 10 minutes
// Set knob to 35% full power
// HeatingStep step0(300, 4.00, 1.0, 0.0, 600, 1.0);
// HeatingStep step1(50, 0.0, 0.0, 0.0, 1, 0);
// --------------------------------------------------------------------------------

StackArray<HeatingStep> heating_schedule;

void PID_fn(void);
void reset_display(void);
void set_pid_tune(double, double, double);

void setup()
{
  Serial.begin(19200);

  // --------------------------------------------------------------------------------
//  heating_schedule.push(step5);
//  heating_schedule.push(step4);
  heating_schedule.push(step3);
 heating_schedule.push(step2);
  heating_schedule.push(step1);
  heating_schedule.push(step0);
  // --------------------------------------------------------------------------------

  TCCR1A = 0; //Reset Timer1 control Registor A

  bitClear(TCCR1B, WGM13); //Set CTC mode
  bitSet(TCCR1B, WGM12);

  bitSet(TCCR1B, CS12); //Set prescaler to 1024
  bitClear(TCCR1B, CS11);
  bitSet(TCCR1B, CS10);

  //Reset Timer1
  TCNT1 = 0;

  //set compare value
  //max value  (16bit Timer) = 65535
  /*******************************************
    To calculate compare value
    OCR1A = (time(s) * clock Freq.)/prescaler
    OCR1A = (1*16*10^6)/1024
  ********************************************/
  OCR1A = 1625; //for 0.104 second
  //OCR1A = 3906;     //for 0.25sec
  //OCR1A = 7812;    //for 0.5sec
  //OCR1A = 15625;   //for 1sec
  //OCR1A = 31250;   //for 2sec

  bitSet(TIMSK1, OCIE1A); // Enable Timer1 compare interrupt
  sei();                  // Enable global interrupts

  delay(2000); // do not remove this delay!
  pinMode(SSR_PIN, OUTPUT);
  pinMode(START_PIN, INPUT);
  digitalWrite(SSR_PIN, LOW);

  g_pidparam[0].Input = T;
  myPID.SetSampleTime(50);
  myPID.SetMode(AUTOMATIC);
  myPID.SetOutputLimits(0, 255); // although the function defaults to 0 to 255, we call this anyway to be safe

  display.begin(SSD1306_SWITCHCAPVCC, 0);

  display.setTextColor(SSD1306_WHITE);

  reset_display();
  delay(100);

  display.drawRect(4, 2, 120, 60, WHITE);

  display.setTextSize(3);
  display.setCursor(8, 8);
  display.print("RTA");

  display.setTextSize(1);
  display.setCursor(8, 35);
  display.print("Folklab Instruments");
  display.display();
  delay(2000);
  reset_display();
  delay(100);
}


ISR(TIMER1_COMPA_vect)
{
  T = probe.readTempC();

  ///// Code below is useful in case the Arduino is recieving NaN values and the issue cannot be fixed otherwise //////////////////////////////////////////////////////////////
  ///// Note: First make sure the thermocouple leads are electrically isolated from the rest of the apparatus (i.e. only electrically connected to the copper shield around the bulb)
  ///// See discourse https://qdev-forum.phas.ubc.ca/t/rapid-thermal-annealer-rta-wiki/44/3
  //    _T = probe.readTempC();
  //    if (!isnan(_T))
  //    {
  //      T = _T;
  //    }
  /////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
}

void loop()
{

  if (START == HIGH)
  {
    if (!heating_schedule.isEmpty())
    {
      PID_fn();
      // after ramping, holding
      heating_schedule.pop(); // pop the last entry from the stack
    }
    else
    {
      cli(); // clear interrupt flag. This prevents any interrupts from occuring
      delay(1000);
      analogWrite(SSR_PIN, 0);
      delay(1000);
      START = LOW;
      sei(); // restart interrupts

    }
  }
  else
  {
    delay(110);
    START = digitalRead(START_PIN);
    reset_display();
    display.setTextSize(2);
    display.setCursor(0, 0);
    display.print("Push START");

    display.setTextSize(1);
    display.setCursor(0, 15);
    display.print("---------------------");

    display.setTextSize(1);
    display.setCursor(0, 20);
    display.print("Loaded sequence:");
    display.setCursor(0, 28);
    display.print(">> " + sequence_name);
    display.setCursor(0, 35);
    display.print("---------------------");



    display.setTextSize(2);
    display.setCursor(0, 45);
    display.println("T:" + String(T, 2) + String(char(247)) + "C");
    display.println();
    display.display();

    serial_fn();

    if (START == HIGH)
    {
      cli(); // clear interrupt flag. This prevents any interrupts from occuring
      START_TIME = millis();
      sei(); // restart interrupts
    }
  }
}

void serial_fn(void)
{
  if (millis() - LastSerialSend > 50)
  {
    LastSerialSend = millis();
    Serial.print(millis());
    Serial.print(',');
    Serial.println(T);
  }
}


void PID_fn(void)
{
  double setpoint = heating_schedule.peek().setpoint;
  double kp = heating_schedule.peek().proportional;
  double ki = heating_schedule.peek().integral;
  double kd = heating_schedule.peek().derivative;
  double ht = heating_schedule.peek().hold_time;
  // temperature difference in ramp
  double delta_t = heating_schedule.peek().delta_t;

  // set the PID parameter
  set_pid_tune(kp, ki, kd);
  g_pidparam[0].Setpoint = setpoint;

  // if the setpoint is delta_t higher, then we fully close the relay
  while ((setpoint - T) >= delta_t)
  {
    delay(110);
    // Pretend to use PID so that has history of Ts
    g_pidparam[0].Input = T;
    myPID.Compute();
    //
    analogWrite(SSR_PIN, 255);
    reset_display();
    display.println(String(T, 2) + String(char(247)) + "C");
    display.println("Ramp to:");
    display.println(String(setpoint, 0) + String(char(247)) + "C");
    display.display();

    serial_fn();
  }

  // if the overshoot is more than delta_t, then we fully open the relay
  while ((T - setpoint) >= delta_t)
  {
    delay(110);
    // Pretend to use PID so that has history of Ts
    g_pidparam[0].Input = T;
    myPID.Compute();
    //
    analogWrite(SSR_PIN, 0);
    reset_display();
    display.println(String(T, 2) + String(char(247)) + "C");
    display.println("Cool to:");
    display.println(String(setpoint, 0) + String(char(247)) + "C");
    display.display();

    serial_fn();
  }

  // the temperature is within delta_t of the setpoint, but more than 1 C away from it
  while (abs(setpoint - T) > 1.0)
  {
    delay(110);
    g_pidparam[0].Input = T;
    myPID.Compute();
    analogWrite(SSR_PIN, g_pidparam[0].Output);
    reset_display();
    display.println(String(T, 2) + String(char(247)) + "C");
    display.println("Ramp to:");
    display.println(String(setpoint, 0) + String(char(247)) + "C");
    display.display();

    serial_fn();
  }

  unsigned long start_time = millis(); // in ms

  // holding
  while ((millis() - start_time) / 1000.0 < ht)
  {
    delay(110);
    g_pidparam[0].Input = T;
    myPID.Compute();
    analogWrite(SSR_PIN, g_pidparam[0].Output);
    reset_display();
    display.println(String(T, 2) + String(char(247)) + "C");
    display.println("Holding");
    display.print((millis() - start_time) / 1000 / 60);
    display.println("mins");
    display.display();

    serial_fn();
  }
}

void set_pid_tune(double kp, double ki, double kd)
{
  g_pidparam[0].kp = kp;
  g_pidparam[0].ki = ki;
  g_pidparam[0].kd = kd;
  myPID.SetTunings(g_pidparam[0].kp, g_pidparam[0].ki, g_pidparam[0].kd);
}

void reset_display(void)
{

  display.clearDisplay();
  display.setCursor(0, 0);
}

void append_to_display(String message)
{
  display.println(message);
}