Pid.h

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/* Copyright 2013-2019 Homegear GmbH
 *
 * libhomegear-base is free software: you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * libhomegear-base is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with libhomegear-base.  If not, see
 * <http://www.gnu.org/licenses/>.
 *
 * In addition, as a special exception, the copyright holders give
 * permission to link the code of portions of this program with the
 * OpenSSL library under certain conditions as described in each
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 * including the two.
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*/

#ifndef _PID_H_
#define _PID_H_

namespace BaseLib
{

class Pid
{
private:
    double _dt;
    double _pMax;
    double _pMin;
    double _oMax;
    double _oMin;
    double _Kp;
    double _Ki;
    double _Kd;
    double _previousError;
    double _integral;

    double clamp(double value, double min, double max);
    double scale(double value, double valueMin, double valueMax, double scaleMin, double scaleMax);
public:
    // Kp -  proportional gain
    // Ki -  Integral gain
    // Kd -  derivative gain
    // dt -  loop interval time
    // pMax - maximum value of process variable
    // pMin - minimum value of process variable
    // oMax - maximum value of output variable
    // oMin - minimum value of output variable
    Pid(double dt, double pMax, double pMin, double oMax, double oMin, double Kp, double Ki, double Kd);

    // Returns the manipulated variable given a setpoint and current process value
    double calculate(double setpoint, double processVariable);
    virtual ~Pid();
};

}

#endif