typedef struct PIDValue
{
    uint32 Ek_Uint32[3];         //差值保存，给定和反馈的差值
    uint8 EkFlag_Uint8[3];     //符号，1则对应的Ek[i]为负数，0为对应的Ek[i]为正数
    uint8   KP_Uint8;
uint8   KI_Uint8;
uint8   KD_Uint8;
uint8   B_Uint8;     //死区电压

uint8   KP;      //显示修改的时候用
uint8   KI;      //
uint8   KD;      //
uint8   B;       //
uint16 Uk_Uint16;    //上一时刻的控制电压
}PIDValueStr;

PIDValueStr xdata PID;

void    PIDProcess(void)
{
uint32 idata Temp[3]; //
uint32 idata PostSum; //正数和
uint32 idata NegSum;   //负数和
Temp[0] = 0;
    Temp[1] = 0;
    Temp[2] = 0;
PostSum = 0;
NegSum = 0;
if( ADPool.Value_Uint16[UINADCH] > ADPool.Value_Uint16[UFADCH] ) //给定大于反馈,则EK为正数
{
     Temp[0] = ADPool.Value_Uint16[UINADCH] - ADPool.Value_Uint16[UFADCH];   //计算Ek[0]
        if( Temp[0] > PID.B_Uint8 )
        {
      //数值移位
            PID.Ek_Uint32[2] = PID.Ek_Uint32[1];
            PID.Ek_Uint32[1] = PID.Ek_Uint32[0];
            PID.Ek_Uint32[0] = Temp[0];
            //符号移位
   PID.EkFlag_Uint8[2] = PID.EkFlag_Uint8[1];
   PID.EkFlag_Uint8[1] = PID.EkFlag_Uint8[0];
   PID.EkFlag_Uint8[0] = 0;                       //当前EK为正数
            Temp[0] = (uint32)PID.KP_Uint8 * PID.Ek_Uint32[0];    // KP*EK0
            Temp[1] = (uint32)PID.KI_Uint8 * PID.Ek_Uint32[1];    // KI*EK1
            Temp[2] = (uint32)PID.KD_Uint8 * PID.Ek_Uint32[2];    // KD*EK2
        }
}
else   //反馈大于给定
{
     Temp[0] = ADPool.Value_Uint16[UFADCH] - ADPool.Value_Uint16[UINADCH];   //计算Ek[0]
        if( Temp[0] > PID.B_Uint8 )
        {
      //数值移位
            PID.Ek_Uint32[2] = PID.Ek_Uint32[1];
            PID.Ek_Uint32[1] = PID.Ek_Uint32[0];
            PID.Ek_Uint32[0] = Temp[0];
            //符号移位
   PID.EkFlag_Uint8[2] = PID.EkFlag_Uint8[1];
   PID.EkFlag_Uint8[1] = PID.EkFlag_Uint8[0];
   PID.EkFlag_Uint8[0] = 1;                       //当前EK为负数
            Temp[0] = (uint32)PID.KP_Uint8 * PID.Ek_Uint32[0];    // KP*EK0
            Temp[1] = (uint32)PID.KI_Uint8 * PID.Ek_Uint32[1];    // KI*EK1
            Temp[2] = (uint32)PID.KD_Uint8 * PID.Ek_Uint32[2];    // KD*EK2
        }
}


    if(PID.EkFlag_Uint8[0]==0)
    {
        PostSum += Temp[0];   //正数和
}
    else
{
        NegSum += Temp[0];    //负数和
}                         // KP*EK0
    if(PID.EkFlag_Uint8[1]!=0)    
    {
        PostSum += Temp[1];   //正数和
}
else
{
        NegSum += Temp[1];    //负数和
}                         // - kI * EK1
    if(PID.EkFlag_Uint8[2]==0)
    {
        PostSum += Temp[2];   //正数和
    }
else
{
        NegSum += Temp[2];    //负数和
}                         // KD * EK2
    PostSum += (uint32)PID.Uk_Uint16;        //
    if( PostSum > NegSum )             // 是否控制量为正数
    {
        Temp[0] = PostSum - NegSum;
        if( Temp[0] < (uint32)ADPool.Value_Uint16[UMAXADCH] )   //小于限幅值则为计算值输出
{
            PID.Uk_Uint16 = (uint16)Temp[0];
}
else
{
            PID.Uk_Uint16 = ADPool.Value_Uint16[UMAXADCH];    //否则为限幅值输出
     }
    }
    else               //控制量输出为负数，则输出0
    {
        PID.Uk_Uint16 = 0;
    }
} 关键字：PID  算法调节  C51程序