PaulS:
#define PPO inputReading1*aref_voltage/1024
Input = analogRead(PPO);
Input = analogRead(PPO); // PID analog input for PPO
What pin are you reading from?
I'm reading from the "const int" of sensors1, sensor2, and sensor3 from pins A0, A1, A2
/****************************************************************
*initiate pins for sensor inputs 1, 2, 3
*****************************************************************/
const int sensor1 = A0; // the analog pin the 02 Sensor Vout pin is connected to
int inputReading1; //declare a variable
const int sensor2 = A1; // the analog pin the 02 Sensor Vout pin is connected to
int inputReading2; // declare a variable
const int sensor3 = A2; // the analog pin the 02 sensor Vout pin is connected to
int inputReading3; // declare a variable
/*****************************************************************/