PidController.h

00001 /**
00002  * @author James Batchelar
00003  *
00004  * @section LICENSE
00005  *
00006  *
00007  * Permission is hereby granted, free of charge, to any person obtaining a copy
00008  * of this software and associated documentation files (the "Software"), to deal
00009  * in the Software without restriction, including without limitation the rights
00010  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
00011  * copies of the Software, and to permit persons to whom the Software is
00012  * furnished to do so, subject to the following conditions:
00013  *
00014  * The above copyright notice and this permission notice shall be included in
00015  * all copies or substantial portions of the Software.
00016  *
00017  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
00018  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
00019  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
00020  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
00021  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
00022  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
00023  * THE SOFTWARE.
00024  *
00025  * @section DESCRIPTION
00026  *
00027  * PID Controller with Integral Clamping
00028  * 
00029  * 
00030  *     
00031  
00032  * @code
00033 #include "mbed.h"
00034 #include "PID.h"
00035 
00036  * @endcode
00037  */
00038 
00039 #include "mbed.h"
00040 
00041 #ifndef PidController_H
00042 #define PidController_H
00043 
00044 //-- Constants used in system
00045 const int RATE = 100;       //--(ms) Time that Calculate mehtod is being called       
00046 const int AUTOMATIC = 0;    //-- In automatic then PID Controls Output
00047 const int MANUAL = 1;       //-- In Manual then User Controls Output directly
00048 
00049 //-- Constructor 
00050 
00051 class PidController{
00052     public:
00053         // Public Methods
00054     
00055         /** Constructor
00056         *
00057         */
00058         PidController();
00059         
00060         /** Performs the PID Calculation
00061         * @param SP - Setpoint (target value) units depends on what PID is controlling
00062         * @param PV - Process Variable (feedback/ measure value) units depends on what PID is controlling
00063         * @return Returns If Controller is in Automatic then returns PID controlled signal. In manual returns the user SP multipled by scalar.
00064         */
00065         int Calculate(float SP, float PV);
00066         
00067         /** Update Internal Seetings
00068         * @param Bias - Added to the PID Calculation
00069         * @param PropGain - Proportional Gain
00070         * @param IntGain - Integral Gain
00071         * @param DiffGain - Differential Gain
00072         * @param OutputMin - Minimum Limit for the Output (units are same as setpoint)
00073         * @param OutputMax - Maximum Limit for the Output (units are same as setpoint)
00074         * @param OutputScale - Multiplier at End of PID loop to convert from engineering units to signal (eg PWM duty cycle)   
00075         */    
00076         void UpdateSettings(float Bias, float PropGain, float IntGain, float DiffGain, float OutputMin, float OutputMax, float OutputScale);
00077         
00078         /** Get the controller mode
00079         * @return 1 = AUTOMATIC, 0 = MANUAL(User has direct contol on output).
00080         */
00081         int GetMode(void){return (int)mode;}
00082         
00083         /** Set the controller in Manual Mode (PID turned off SP is writted directly to output)
00084         */
00085         void SetManual(void){mode = MANUAL;}
00086         
00087         /** Set the controller in Automatic Mode (PID turned on)
00088         */
00089         void SetAutomatic(void){mode = AUTOMATIC;}
00090         
00091         /** Enable Diagnostics for HMI
00092         */
00093         void StartDiag(void);
00094         
00095         /** Disable Diagnostics for HMI
00096         */
00097         void EndDiag(void);
00098         
00099         /** Build a string to send back to HMI to Graph PID
00100         */
00101         void BuildDiagMessage(float SP, float PV, float PWM, float PropAction, float IntAction, float DifAction);
00102         
00103         /** Check to see if the controller is collecting diagnostics data
00104         * @return true then a diagnostics message is been created.
00105         */
00106         bool DiagnosticsEnabled(void){return collectDiagnostics;}
00107         
00108         int GetElapsedtime(void){return elapsedTime;}
00109         
00110         // Made Public as im lazy
00111         char diagMsg[65];
00112         
00113     private:
00114         bool mode;
00115         
00116         //-- For Diagnostics to GUI
00117         bool collectDiagnostics;
00118         int elapsedTime;
00119         
00120         //-- For PID Calculations
00121         float bias, scalar;
00122         float error;
00123         float lastError;
00124         float accumError;
00125         float minLimit, maxLimit;
00126         float K_p,K_i,K_d;
00127     };
00128     
00129 #endif
00130     
00131     
00132     
00133 
00134 
00135