PID.h

00001 #ifndef PID_H
00002 #define PID_H
00003  
00004 #include "mbed.h"
00005 
00006 class PID 
00007 { 
00008 public: 
00009       #define AUTOMATIC 1
00010       #define MANUAL    0
00011       #define DIRECT  0
00012       #define REVERSE  1
00013       #define P_ON_M 0
00014       #define P_ON_E 1
00015     Timer PIDtimer;
00016     PID(volatile double* Input, volatile double* Output, volatile double* Setpoint,
00017         double Kp, double Ki, double Kd, int POn, int ControllerDirection); 
00018     void SetMode(int Mode);               // * sets PID to either Manual (0) or Auto (non-0)
00019 
00020     bool Compute();                       // * performs the PID calculation.  it should be
00021                                           //   called every time loop() cycles. ON/OFF and
00022                                           //   calculation frequency can be set using SetMode
00023                                           //   SetSampleTime respectively
00024 
00025     void SetOutputLimits(double, double); // * clamps the output to a specific range. 0-255 by default, but
00026                                                               //   it's likely the user will want to change this depending on
00027                                                               //   the application
00028     
00029 
00030 
00031   //available but not commonly used functions ********************************************************
00032     void SetTunings(double, double,       // * While most users will set the tunings once in the 
00033                     double);                //   constructor, this function gives the user the option
00034                                           //   of changing tunings during runtime for Adaptive control
00035     void SetTunings(double, double,       // * overload for specifying proportional mode
00036                     double, int);             
00037 
00038     void SetControllerDirection(int);     // * Sets the Direction, or "Action" of the controller. DIRECT
00039                                           //   means the output will increase when error is positive. REVERSE
00040                                           //   means the opposite.  it's very unlikely that this will be needed
00041                                           //   once it is set in the constructor.*/
00042     void SetSampleTime(int);              // * sets the frequency, in Milliseconds, with which 
00043                                           //   the PID calculation is performed.  default is 100
00044                                           
00045                                           
00046 
00047                                           
00048   //Display functions ****************************************************************
00049     double GetKp();                       // These functions query the pid for interal values.
00050     double GetKi();                       //  they were created mainly for the pid front-end,
00051     double GetKd();                       // where it's important to know what is actually 
00052     int GetMode();                        //  inside the PID.
00053     int GetDirection();                   //
00054 
00055   private:
00056     void Initialize();
00057     
00058     double dispKp;              // * we'll hold on to the tuning parameters in user-entered 
00059     double dispKi;              //   format for display purposes
00060     double dispKd;              //
00061     
00062     double kp;                  // * (P)roportional Tuning Parameter
00063     double ki;                  // * (I)ntegral Tuning Parameter
00064     double kd;                  // * (D)erivative Tuning Parameter
00065 
00066     int controllerDirection;
00067     int pOn;
00068 
00069     volatile double *myInput;              // * Pointers to the Input, Output, and Setpoint variables
00070     volatile double *myOutput;             //   This creates a hard link between the variables and the 
00071     volatile double *mySetpoint;           //   PID, freeing the user from having to constantly tell us
00072                                   //   what these values are.  with pointers we'll just know.
00073               
00074     double lastTime;
00075     double outputSum, lastInput;
00076 
00077     double SampleTime;
00078     double outMin, outMax;
00079     bool inAuto, pOnE;
00080     
00081 };
00082 
00083 #endif
00084