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#include <max6675.h>

#include <ModbusRtu.h>



// data array for modbus network sharing

uint16_t au16data[16] = {

  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1

};



/**

    Modbus object declaration

    u8id : node id = 0 for master, = 1..247 for slave

    u8serno : serial port (use 0 for Serial)

    u8txenpin : 0 for RS-232 and USB-FTDI

                 or any pin number > 1 for RS-485

*/

Modbus slave(1, 0, 0); // this is slave @1 and RS-232 or USB-FTDI



// Pins for thermocouple MAX6675

int thermoDO = 6;

int thermoCS = 5;

int thermoCLK = 4;



MAX6675 thermocouple(thermoCLK, thermoCS, thermoDO);



// declare variable for Arduino pin connected to solid state relay (SSR)

int relay = 9;



// declare variables for Arduino pins connected to fan controller (L293N)

int fan = 10; // ENA of L239N

int in1 = 11; // IN1 of L239N

int in2 = 12; // IN1 of L239N



// declare variables for Arduino pins to power MAX6675:

int vccPin = 3; // 5v power of MAX6675

int gndPin = 2; // gnd of MAX6675



void setup() {

  slave.begin( 19200); // 19200 baud, 8-bits, even, 1-bit stop

  // use Arduino pins

  pinMode(relay, OUTPUT);

  pinMode(fan, OUTPUT); 

  pinMode(in1, OUTPUT); 

  pinMode(in2, OUTPUT); 

   

  pinMode(vccPin, OUTPUT); digitalWrite(vccPin, HIGH);

  pinMode(gndPin, OUTPUT); digitalWrite(gndPin, LOW);

  delay(500);

}



void loop() {

  //write current thermocouple value

  au16data[2] = ((uint16_t) thermocouple.readCelsius() * 100);



  //write current fan value for air control

  analogWrite(fan, (au16data[5] / 100.0) * 255);

  digitalWrite(in1, HIGH);

  digitalWrite(in2, LOW);



  //poll modbus registers

  slave.poll( au16data, 16 );



  // heater control:

  digitalWrite(relay, HIGH);

  delay(au16data[4] * 10);

  digitalWrite(relay, LOW);

  delay((100 - au16data[4]) * 10 - 1);

}