   pinMode(EXT_PIN, OUTPUT); // Extrusion Motor  
   pinMode(SPL_PIN, OUTPUT); // Spooling Motor
   pinMode(HTR_PIN, OUTPUT); // Heater
+  pinMode(ENBL_PIN, OUTPUT); // Power Supply Enable
   pinMode(clockPin, INPUT);  
   pinMode(dataPin, INPUT); 
   

  digitalWrite(EXT_PIN, LOW);
  digitalWrite(SPL_PIN, LOW);
  digitalWrite(HTR_PIN, LOW);

  Serial.begin(9600);
  start_millis = millis();

// Set up global variables
const byte EXT_PIN = 11;
const byte SPL_PIN = 10;
const byte HTR_PIN = 9;
const byte ENBL_PIN = 4;
const byte HTR_LED = 7;
const byte HOT_LED = 6;

// Serial input parameter editing for PID
boolean input_complete = false;
