Arduino Subcooling code

[buffalobillpatrick]

Subcooling only code:

/********************************************************
 *
 * ARDUINO R290 Calculate Subcooling
 *
 * Note: REQUIRED SENSOR
 *       High Pressure Sensor:     0-300PSI with output of .5 -> 4.5vdc
 *
 * If in DEBUG mode, values are forced to test code function
 *
 * In Void Loop:
 *
 *     , read Hi Side Pressure Transducer
 *
 *     , if RAW_ADC is in bounds:
 *     , convert Raw_ADC to PSI
 *     , calc_R290_Saturated_Temp
 *     , read Subcooling_Temp_sensor (analog NTC thermistor)
 *     , calc Subcooling
 *
 *     , if RAW_ADC is out of bounds, Hang Forever
 *
 * Repeat Void loop
 *
 *
 * Change History: 
 * 02/18/15 Coded, BBP
 *
 *
 *
 ********************************************************/

#if defined(ARDUINO) && ARDUINO >= 100
  #include "Arduino.h"
  #else
  #include "WProgram.h"
  #endif

#include <Wire.h>
#include <LCD.h>
#include <LiquidCrystal_I2C.h>


#define DEBUG 1
//#define DEBUG 0


#define I2C_ADDR    0x3F // <<----- Add your address here.  Find it from I2C Scanner
                       //D3
#define BACKLIGHT_PIN     3  //define LCD digital pins
#define En_pin  2
#define Rw_pin  1             //can't use D0 & D1 Tx, Rx
#define Rs_pin  0
#define D4_pin  4
#define D5_pin  5              //can use D2 -> D12 below in code
#define D6_pin  6
#define D7_pin  7

LiquidCrystal_I2C lcd(I2C_ADDR,En_pin,Rw_pin,Rs_pin,D4_pin,D5_pin,D6_pin,D7_pin);

#define SDA                           A4  //RESERVE I2C for LCD           
#define SCL                           A5  

//  pinMode(A0, OUTPUT);     //This works acording 
                             //  http://arduino.cc/en/Tutorial/AnalogInputPins
//  digitalWrite(A0, HIGH);  //


#define Subcooling_Temp_sensor_pin        A0 
#define Hi_Side_Pressure_Transducer_pin   A1


#define ADC_Low_Limit        102.0    //ADC of .5v
#define ADC_Hi_Limit         921.0    //ADC of 4.5v
#define PSI_min                0.0
#define PSI_max              300.0

 
float Raw_ADC, Hi_Side_PSI, Subcooling_T, Subcooling, Saturated_Temp;

int Y;


void setup(void)       //Start Setup
  {
        
  pinMode (Subcooling_Temp_sensor_pin,      INPUT);
  pinMode (Hi_Side_Pressure_Transducer_pin, INPUT);

 
 // Serial.begin(9600); // start serial communication
 // delay(10000);      //time to enable monitor window
 // Serial.println(F("........Hello world!......."));
 // delay(100); 
 
  
  lcd.begin (16,2); //  <<----- My LCD is 16x2
  lcd.clear();
 
  //Switch on the backlight
  lcd.setBacklightPin(BACKLIGHT_PIN,POSITIVE);
  lcd.setBacklight(HIGH);


  lcd.clear();
  lcd.home (); // go home
  lcd.print(F("R290_SUBCOOL_3"));
  delay(10000);


  if(DEBUG)
  {       
  lcd.clear();
  lcd.home (); // go home
  lcd.print(F("DEBUG = ON"));
  delay(10000);
  }
  else 
  {       
  lcd.clear();
  lcd.home (); // go home
  lcd.print(F("DEBUG = OFF"));
  delay(10000);
  }

  }    //end setup




  void loop ()
{ 
 
  Raw_ADC = analogRead(Hi_Side_Pressure_Transducer_pin);  //read Hi Side pressure
 
if(DEBUG){  Raw_ADC = 921;}


  //Raw_ADC Bounds check
  if ((Raw_ADC >= ADC_Low_Limit) && (Raw_ADC <= ADC_Hi_Limit))
  {
  // in bounds, convert Raw_ADC to PSI
  
  Hi_Side_PSI = mapfloat(Raw_ADC, ADC_Low_Limit, ADC_Hi_Limit, PSI_min, PSI_max); 
  
  lcd.clear();
  lcd.home (); // go home
  lcd.print(F("SUBCOL_PSI="));
  lcd.print(Hi_Side_PSI);  
  delay(10000);  
    
  Saturated_Temp = calc_R290_Saturated_Temp(Hi_Side_PSI); 

  lcd.clear();
  lcd.home (); // go home
  lcd.print(F("SAT_T="));
  lcd.print(Saturated_Temp);  
  lcd.print(F("*F"));
  delay(10000);
 
    
//read Subcooling Temp sensor
  Subcooling_T = (Read_10K_NTC (Subcooling_Temp_sensor_pin)); 
  
if(DEBUG){ Subcooling_T = 150;}
      
  lcd.clear();
  lcd.home (); // go home
  lcd.print(F("SUBCOL_T="));
  lcd.print(Subcooling_T);  
  lcd.print(F("*F"));
  delay(10000); 
    
  Subcooling = Subcooling_T - Saturated_Temp;  //calc Subcooling
  
  lcd.clear();
  lcd.home (); // go home
  lcd.print(F("SUBCOOL="));
  lcd.print(Subcooling);  
  lcd.print(F("*F"));
  delay(10000);    
   
  }  //end if in bounds
 
  
  else         //ADC out of bounds
  {           
  lcd.clear();
  lcd.home (); // go home
  lcd.print(F("RAW_PSI_NG"));   
  lcd.setCursor(0,1);
  lcd.print(F("HANG_FOREVER_1"));   
  do{Y = Y;} while (Y == Y);  //hang forever
  }     
 
  
}  //end forever loop





  
float mapfloat(float x, float in_min, float in_max, float out_min, float out_max)
{
  return (x - in_min) * (out_max - out_min) / (in_max - in_min) + out_min;
}




float calc_R290_Saturated_Temp(float psi)
{ 
//MMF Model: y=(a*b+c*x^d)/(b+x^d)
//Coefficient Data:
float a = -6.63511955666E+001;
float b =  6.30623048298E+001;
float c = 7.72874234743E+002;
float d = 5.32503085812E-001;
float p;

  p = pow(psi,d);

  return (((a * b) + (c * p)) / (b + p ));
}




int Read_10K_NTC (int which_sensor)
{   
  #define sample_cnt 30
  
  float alpha =   0.9;     // factor to tune
  float average = 0.0;
  float steinhart;
  
  int I;
 
// resistance at 25 degrees C
#define THERMISTORNOMINAL 10000

// TEMP. for nominal resistance (almost always 25 C)
#define TEMPERATURENOMINAL 25

// The beta coefficient of the thermistor (usually 3000-4000)
#define BCOEFFICIENT 3892

// the value of the series resistor
#define SERIESRESISTOR 10000

  
  for (I=0; I< sample_cnt; I++) 
  {  
  average =  alpha * analogRead(which_sensor) + (1-alpha) * average;
  delay(10);
  }
 
  // convert the value to resistance
  average = 1023 / average - 1;
  average = SERIESRESISTOR / average;
  steinhart = average / THERMISTORNOMINAL;     // (R/Ro)
  steinhart = log(steinhart);                  // ln(R/Ro)
  steinhart /= BCOEFFICIENT;                   // 1/B * ln(R/Ro)
  steinhart += 1.0 / (TEMPERATURENOMINAL + 273.15); // + (1/To)
  steinhart = 1.0 / steinhart;                 // Invert
  steinhart -= 273.15;                         // convert to C
  
  return (round(steinhart * 1.8) + 32);       // round to whole number 
                                              // & convert to F            
}  // end of Read_10K_NTC