PID Example Reading analog input control Motor from VR

/********************************************************
 * PID Basic Example
 * Reading analog input 0 to control analog PWM output 3
 ********************************************************/

#include <PID_v1.h>
#include <ModbusRtu.h>

#define PIN_INPUT 1
#define PIN_OUTPUT 3
#define E2 3
#define I3 3
#define I4 13

// data array for modbus network sharing
uint16_t au16data[16];

//Define Variables we'll be connecting to
double Setpoint, Input, Output;

//Specify the links and initial tuning parameters
//double Kp=1.0, Ki=0.5, Kd=1.0;
double Kp=1.4,Ki=0, Kd=0;
//double Kp=1, Ki=0.18, Kd=0;

PID myPID(&Input, &Output, &Setpoint, Kp, Ki, Kd, DIRECT);
Modbus slave(1,1,0); // this is slave @1 and RS-232 or USB-FTDI

void setup()
{

  //initialize the variables we're linked to
  Setpoint = analogRead(A4);
  Input = analogRead(A5);

  pinMode(E2,OUTPUT);
  pinMode(I3,OUTPUT);
  pinMode(I4,OUTPUT);

  //turn the PID on
  myPID.SetMode(AUTOMATIC);
  myPID.SetSampleTime(50); //200ms
  myPID.SetOutputLimits(0, 255);

  Serial.begin(9600);
  slave.begin( 19200 ); // baud-rate at 19200
}

void loop()
{
 Setpoint = analogRead(A4);
  Input = analogRead(A5);
  myPID.Compute();

  digitalWrite(I3,HIGH);
  digitalWrite(I4,LOW);
  analogWrite(PIN_OUTPUT, Output);

 Serial.print("\n");
 Serial.print(Setpoint);
 Serial.print("\t");
 Serial.print(Input);
 //Serial.print("\t");
 //Serial.print( Output);
 Serial.print("\t");
 Serial.print( 700);
  Serial.print("\t");
 Serial.print( 300);

 au16data[1]= Input;
 au16data[2]= Setpoint-Input;
 //Setpoint = au16data[3];
 Kp = au16data[4];
 Ki = au16data[5];
 Kd = au16data[6];
 myPID.SetMode(AUTOMATIC);

 au16data[7]= Kp;//myPID.GetKp();
 au16data[8]= Ki;//myPID.GetKi();
 au16data[9]= Kd;//myPID.GetKd();

 PID myPID(&Input, &Output, &Setpoint, Kp, Ki, Kd, DIRECT);
 slave.poll( au16data, 16 );

}