PID-Library (C Version)

PID Controller library for ARM Cortex M (STM32)

Download Arduino Library : Arduino-PID-Library

Release

• Version : 1.0.0

• Type : Embedded Software.

• Support :

           - ARM STM32 series  
  

• Program Language : C/C++

• Properties :

• Changes :

• Required Library/Driver :

Overview

Initialization and de-initialization functions:

void PID(PID_TypeDef *uPID, double *Input, double *Output, double *Setpoint, double Kp, double Ki, double Kd, PIDPON_TypeDef POn, PIDCD_TypeDef ControllerDirection);
void PID2(PID_TypeDef *uPID, double *Input, double *Output, double *Setpoint, double Kp, double Ki, double Kd, PIDCD_TypeDef ControllerDirection);

Operation functions:

/* ::::::::::: Computing ::::::::::: */
uint8_t PID_Compute(PID_TypeDef *uPID);

/* ::::::::::: PID Mode :::::::::::: */
void            PID_SetMode(PID_TypeDef *uPID, PIDMode_TypeDef Mode);
PIDMode_TypeDef PID_GetMode(PID_TypeDef *uPID);

/* :::::::::: PID Limits ::::::::::: */
void PID_SetOutputLimits(PID_TypeDef *uPID, double Min, double Max);

/* :::::::::: PID Tunings :::::::::: */
void PID_SetTunings(PID_TypeDef *uPID, double Kp, double Ki, double Kd);
void PID_SetTunings2(PID_TypeDef *uPID, double Kp, double Ki, double Kd, PIDPON_TypeDef POn);

/* ::::::::: PID Direction ::::::::: */
void          PID_SetControllerDirection(PID_TypeDef *uPID, PIDCD_TypeDef Direction);
PIDCD_TypeDef PID_GetDirection(PID_TypeDef *uPID);

/* ::::::::: PID Sampling :::::::::: */
void PID_SetSampleTime(PID_TypeDef *uPID, int32_t NewSampleTime);

/* ::::::: Get Tunings Param ::::::: */
double PID_GetKp(PID_TypeDef *uPID);
double PID_GetKi(PID_TypeDef *uPID);
double PID_GetKd(PID_TypeDef *uPID);

Macros:

non   

Guide

This library can be used as follows:

1. Add pid.h header

2. Create PID struct and initialize it, for example:

• Initializer:

  PID(PID_TypeDef *uPID, double *Input, double *Output, double *Setpoint, double Kp, double Ki, double Kd, PIDPON_TypeDef POn, PIDCD_TypeDef ControllerDirection);

• Parameters:

  • uPID : Pointer to pid struct
  • Input : The variable we're trying to control (double)
  • Output : The variable that will be adjusted by the pid (double)
  • Setpoint : The value we want to Input to maintain (double)
  • Kp,Ki,Kd : Tuning Parameters. these affect how the pid will change the output (double>=0)
  • POn : Either P_ON_E (Default) or P_ON_M. Allows Proportional on Measurement to be specified.
  • ControllerDirection : Either DIRECT or REVERSE. determines which direction the output will move when faced with a given error. DIRECT is most common

• Example:

  PID_TypeDef TPID;
  
  double Temp, PIDOut, TempSetpoint;
  
  PID(&TPID, &Temp, &PIDOut, &TempSetpoint, 2, 5, 1, _PID_P_ON_E, _PID_CD_DIRECT);

3. Set 'mode', 'sample time' and 'output limit', for example:

• Functions:

  void PID_SetMode(PID_TypeDef *uPID, PIDMode_TypeDef Mode);
  void PID_SetOutputLimits(PID_TypeDef *uPID, double Min, double Max);
  void PID_SetSampleTime(PID_TypeDef *uPID, int32_t NewSampleTime);

• Parameters:

  • uPID : Pointer to pid struct
  • Mode : _PID_MODE_AUTOMATIC or _PID_MODE_MANUAL
  • Min : Low end of the range. must be < max (double)
  • Max : High end of the range. must be > min (double)
  • NewSampleTime : How often, in milliseconds, the PID will be evaluated. (int>0)

• Example:

  PID_SetMode(&TPID, _PID_MODE_AUTOMATIC);
  PID_SetSampleTime(&TPID, 500);
  PID_SetOutputLimits(&TPID, 1, 100);

4. Using Compute function, for example:

PID_Compute(&TPID);

Examples

Example 1: PID Compute for temperature

#include "main.h"
#include "pid.h"

PID_TypeDef TPID;

char OutBuf[50];
double Temp, PIDOut, TempSetpoint;

int main(void)
{
	
  HW_Init();
  
  PID(&TPID, &Temp, &PIDOut, &TempSetpoint, 2, 5, 1, _PID_P_ON_E, _PID_CD_DIRECT);
	
  PID_SetMode(&TPID, _PID_MODE_AUTOMATIC);
  PID_SetSampleTime(&TPID, 500);
  PID_SetOutputLimits(&TPID, 1, 100);
  
    while (1) 
    {
  
      Temp = GetTemp();
      PID_Compute(&TPID);
      
      sprintf(OutBuf, "Temp%3.2f : %u\n", Temp, (uint16_t)PIDOut);
      UART_Transmit((uint8_t *)OutBuf, strlen(OutBuf));
      
      Delay_ms(500);
    
    }
}
   

Tests performed:

• Run on STM32 Fx cores

Developers:

• Majid Derhambakhsh