C51 COMPILER V6.10  PID_F1                                                                 05/19/2007 01:38:18 PAGE 1   


C51 COMPILER V6.10, COMPILATION OF MODULE PID_F1
OBJECT MODULE PLACED IN .\PID_f1.OBJ
COMPILER INVOKED BY: C:\Keil\C51\BIN\C51.EXE .\PID_f1.c BROWSE DEBUG OBJECTEXTEND

stmt level    source

   1          /*------------------------------------------------------------------*-
   2          
   3             PID_f1.C (v1.00)
   4          
   5            ------------------------------------------------------------------
   6          
   7             Simple PID control implementation. 
   8             
   9             See Chapter 35 for details.
  10          
  11               
  12             COPYRIGHT
  13             ---------
  14          
  15             This code is from the book:
  16          
  17             PATTERNS FOR TIME-TRIGGERED EMBEDDED SYSTEMS by Michael J. Pont 
  18             [Pearson Education, 2001; ISBN: 0-201-33138-1].
  19          
  20             This code is copyright (c) 2001 by Michael J. Pont.
  21           
  22             See book for copyright details and other information.
  23          
  24          -*------------------------------------------------------------------*/
  25          
  26          #include "PID_f1.h"
  27          
  28          // ------ Private constants ----------------------------------------
  29          
  30          #define PID_KP (0.2f)             // Proportional gain  
  31          #define PID_KI (0.01f)            // Integral gain          
  32          #define PID_KD (0.01f)            // Differential gain  
  33          
  34          #define PID_MAX (1.0f)            // Maximum PID controller output
  35          #define PID_MIN (0.0f)            // Minimum PID controller output
  36          
  37          // ------ Private variable definitions------------------------------
  38          
  39          static float Sum_G;       // Integrator component
  40          static float Old_error_G; // Previous error value
  41          
  42          /*------------------------------------------------------------------*-
  43          
  44            PID_Control()
  45          
  46            Simple floating-point version.
  47            
  48            See text for details.
  49            
  50          -*------------------------------------------------------------------*/
  51          float PID_Control(float Error, float Control_old)
  52             {
  53   1         // Proportional term   
  54   1         float Control_new = Control_old + (PID_KP * Error);
  55   1      
C51 COMPILER V6.10  PID_F1                                                                 05/19/2007 01:38:18 PAGE 2   

  56   1         // Integral term
  57   1         Sum_G += Error;
  58   1         Control_new += PID_KI * Sum_G;
  59   1      
  60   1         // Differential term
  61   1         Control_new += (PID_KD * SAMPLE_RATE * (Error - Old_error_G));
  62   1         
  63   1         // Control_new cannot exceed PID_MAX or fall below PID_MIN    
  64   1         if (Control_new > PID_MAX) 
  65   1            {
  66   2            Control_new = PID_MAX; 
  67   2            }
  68   1         else
  69   1            {
  70   2            if (Control_new < PID_MIN) 
  71   2               {
  72   3               Control_new = PID_MIN; 
  73   3               }
  74   2            }    
  75   1       
  76   1          // Store error value
  77   1          Old_error_G = Error;
  78   1      
  79   1          return Control_new;
  80   1          }
  81          
  82          /*------------------------------------------------------------------*-
  83            ---- END OF FILE -------------------------------------------------
  84          -*------------------------------------------------------------------*/


MODULE INFORMATION:   STATIC OVERLAYABLE
   CODE SIZE        =    275    ----
   CONSTANT SIZE    =   ----    ----
   XDATA SIZE       =   ----    ----
   PDATA SIZE       =   ----    ----
   DATA SIZE        =      8      12
   IDATA SIZE       =   ----    ----
   BIT SIZE         =   ----    ----
END OF MODULE INFORMATION.


C51 COMPILATION COMPLETE.  0 WARNING(S),  0 ERROR(S)