Question

PID算法温控C语言

我在做一个89S51单片机的温控试验，要求是1升水的保温。温度任意设定，要求用C语言编写PID算法来实现温度控制（使用1个18B20传感器）要求温度精确小于0.5度。急求高手写一段程序，让小弟学习学习

Answer 1

#include<reg51.h>
#include<intrins.h>
#include<math.h>
#include<string.h>
struct
PID
{
unsigned
int
SetPoint;
//
设定目标
Desired
Value
unsigned
int
Proportion;
//
比例常数
Proportional
Const
unsigned
int
Integral;
//
积分常数
Integral
Const
unsigned
int
Derivative;
//
微分常数
Derivative
Const
unsigned
int
LastError;
//
Error[-1]
unsigned
int
PrevError;
//
Error[-2]
unsigned
int
SumError;
//
Sums
of
Errors
};
struct
PID
spid;
//
PID
Control
Structure
unsigned
int
rout;
//
PID
Response
(Output)
unsigned
int
rin;
//
PID
Feedback
(Input)
sbit
data1=P1^0;
sbit
clk=P1^1;
sbit
plus=P2^0;
sbit
subs=P2^1;
sbit
stop=P2^2;
sbit
output=P3^4;
sbit
DQ=P3^3;
unsigned
char
flag,flag_1=0;
unsigned
char
high_time,low_time,count=0;//占空比调节参数
unsigned
char
set_temper=35;
unsigned
char
temper;
unsigned
char
i;
unsigned
char
j=0;
unsigned
int
s;
/***********************************************************
延时子程序,延时时间以12M晶振为准,延时时间为30us×time
***********************************************************/
void
delay(unsigned
char
time)
{
unsigned
char
m,n;
for(n=0;n<time;n++)
for(m=0;m<2;m++){}
}
/***********************************************************
写一位数据子程序
***********************************************************/
void
write_bit(unsigned
char
bitval)
{
EA=0;
DQ=0;
/*拉低DQ以开始一个写时序*/
if(bitval==1)
{
_nop_();
DQ=1;
/*如要写1，则将总线置高*/
}
delay(5);
/*延时90us供DA18B20采样*/
DQ=1;
/*释放DQ总线*/
_nop_();
_nop_();
EA=1;
}
/***********************************************************
写一字节数据子程序
***********************************************************/
void
write_byte(unsigned
char
val)
{
unsigned
char
i;
unsigned
char
temp;
EA=0;
TR0=0;
for(i=0;i<8;i++)
/*写一字节数据，一次写一位*/
{
temp=val>>i;
/*移位操作，将本次要写的位移到最低位*/
temp=temp&1;
write_bit(temp);
/*向总线写该位*/
}
delay(7);
/*延时120us后*/
//
TR0=1;
EA=1;
}
/***********************************************************
读一位数据子程序
***********************************************************/
unsigned
char
read_bit()
{
unsigned
char
i,value_bit;
EA=0;
DQ=0;
/*拉低DQ，开始读时序*/
_nop_();
_nop_();
DQ=1;
/*释放总线*/
for(i=0;i<2;i++){}
value_bit=DQ;
EA=1;
return(value_bit);
}
/***********************************************************
读一字节数据子程序
***********************************************************/
unsigned
char
read_byte()
{
unsigned
char
i,value=0;
EA=0;
for(i=0;i<8;i++)
{
if(read_bit())
/*读一字节数据，一个时序中读一次，并作移位处理*/
value|=0x01<<i;
delay(4);
/*延时80us以完成此次都时序，之后再读下一数据*/
}
EA=1;
return(value);
}
/***********************************************************
复位子程序
***********************************************************/
unsigned
char
reset()
{
unsigned
char
presence;
EA=0;
DQ=0;
/*拉低DQ总线开始复位*/
delay(30);
/*保持低电平480us*/
DQ=1;
/*释放总线*/
delay(3);
presence=DQ;
/*获取应答信号*/
delay(28);
/*延时以完成整个时序*/
EA=1;
return(presence);
/*返回应答信号，有芯片应答返回0,无芯片则返回1*/
}
/***********************************************************
获取温度子程序
***********************************************************/
void
get_temper()
{
unsigned
char
i,j;
do
{
i=reset();
/*复位*/
}while(i!=0);
/*1为无反馈信号*/
i=0xcc;
/*发送设备定位命令*/
write_byte(i);
i=0x44;
/*发送开始转换命令*/
write_byte(i);
delay(180);
/*延时*/
do
{
i=reset();
/*复位*/
}while(i!=0);
i=0xcc;
/*设备定位*/
write_byte(i);
i=0xbe;
/*读出缓冲区内容*/
write_byte(i);
j=read_byte();
i=read_byte();
i=(i<<4)&0x7f;
s=(unsigned
int)(j&0x0f);
s=(s*100)/16;
j=j>>4;
temper=i|j;
/*获取的温度放在temper中*/
}
/*====================================================================================================
Initialize
PID
Structure
=====================================================================================================*/
void
PIDInit
(struct
PID
*pp)
{
memset
(
pp,0,sizeof(struct
PID));
}
/*====================================================================================================
PID计算部分
=====================================================================================================*/
unsigned
int
PIDCalc(
struct
PID
*pp,
unsigned
int
NextPoint
)
{
unsigned
int
dError,Error;
Error
=
pp->SetPoint
-
NextPoint;
//
偏差
pp->SumError
+=
Error;
//
积分
dError
=
pp->LastError
-
pp->PrevError;
//
当前微分
pp->PrevError
=
pp->LastError;
pp->LastError
=
Error;
return
(pp->Proportion
*
Error
//
比例项
+
pp->Integral
*
pp->SumEror
//
积分项
+
pp->Derivative
*
dError);
//
微分项
}
/***********************************************************
温度比较处理子程序
***********************************************************/
compare_temper()
{
unsigned
char
i;
if(set_temper>temper)
{
if(set_temper-temper>1)
{
high_time=100;
low_time=0;
}
else
{
for(i=0;i<10;i++)
{
get_temper();
rin
=
s;
//
Read
Input
rout
=
PIDCalc
(
&spid,rin
);
//
Perform
PID
Interation
}
if
(high_time<=100)
high_time=(unsigned
char)(rout/800);
else
high_time=100;
low_time=
(100-high_time);
}
}
else
if(set_temper<=temper)
{
if(temper-set_temper>0)
{
high_time=0;
low_time=100;
}
else
{
for(i=0;i<10;i++)
{
get_temper();
rin
=
s;
//
Read
Input
rout
=
PIDCalc
(
&spid,rin
);
//
Perform
PID
Interation
}
if
(high_time<100)
high_time=(unsigned
char)(rout/10000);
else
high_time=0;
low_time=
(100-high_time);
}
}
//
else
//
{}
}
/*****************************************************
T0中断服务子程序，用于控制电平的翻转
,40us*100=4ms周期
******************************************************/
void
serve_T0()
interrupt
1
using
1
{
if(++count<=(high_time))
output=1;
else
if(count<=100)
{
output=0;
}
else
count=0;
TH0=0x2f;
TL0=0xe0;
}
/*****************************************************
串行口中断服务程序，用于上位机通讯
******************************************************/
void
serve_sio()
interrupt
4
using
2
{
/*
EA=0;
RI=0;
i=SBUF;
if(i==2)
{
while(RI==0){}
RI=0;
set_temper=SBUF;
SBUF=0x02;
while(TI==0){}
TI=0;
}
else
if(i==3)
{
TI=0;
SBUF=temper;
while(TI==0){}
TI=0;
}
EA=1;
*/
}
void
disp_1(unsigned
char
disp_num1[6])
{
unsigned
char
n,a,m;
for(n=0;n<6;n++)
{
//
k=disp_num1[n];
for(a=0;a<8;a++)
{
clk=0;
m=(disp_num1[n]&1);
disp_num1[n]=disp_num1[n]>>1;
if(m==1)
data1=1;
else
data1=0;
_nop_();
clk=1;
_nop_();
}
}
}
/*****************************************************
显示子程序
功能：将占空比温度转化为单个字符，显示占空比和测得到的温度
******************************************************/
void
display()
{
unsigned
char
code
number[]={0xfc,0x60,0xda,0xf2,0x66,0xb6,0xbe,0xe0,0xfe,0xf6};
unsigned
char
disp_num[6];
unsigned
int
k,k1;
k=high_time;
k=k%1000;
k1=k/100;
if(k1==0)
disp_num[0]=0;
else
disp_num[0]=0x60;
k=k%100;
disp_num[1]=number[k/10];
disp_num[2]=number[k%10];
k=temper;
k=k%100;
disp_num[3]=number[k/10];
disp_num[4]=number[k%10]+1;
disp_num[5]=number[s/10];
disp_1(disp_num);
}
/***********************************************************
主程序
***********************************************************/
main()
{
unsigned
char
z;
unsigned
char
a,b,flag_2=1,count1=0;
unsigned
char
phil[]={2,0xce,0x6e,0x60,0x1c,2};;
TMOD=0x21;
TH0=0x2f;
TL0=0x40;
SCON=0x50;
PCON=0x00;
TH1=0xfd;
TL1=0xfd;
PS=1;
EA=1;
EX1=0;
ET0=1;
ES=1;
TR0=1;
TR1=1;
high_time=50;
low_time=50;
PIDInit
(
&spid
);
//
Initialize
Structure
spid.Proportion
=
10;
//
Set
PID
Coefficients
spid.Integral
=
8;
spid.Derivative
=6;
spid.SetPoint
=
100;
//
Set
PID
Setpoint
while(1)
{
if(plus==0)
{
EA=0;
for(a=0;a<5;a++)
for(b=0;b<102;b++){}
if(plus==0)
{
set_temper++;
flag=0;
}
}
else
if(subs==0)
{
for(a=0;a<5;a++)
for(b=0;a<102;b++){}
if(subs==0)
{
set_temper--;
flag=0;
}
}
else
if(stop==0)
{
for(a=0;a<5;a++)
for(b=0;b<102;b++){}
if(stop==0)
{
flag=0;
break;
}
EA=1;
}
get_temper();
b=temper;
if(flag_2==1)
a=b;
if((abs(a-b))>5)
temper=a;
else
temper=b;
a=temper;
flag_2=0;
if(++count1>30)
{
display();
count1=0;
}
compare_temper();
}
TR0=0;
z=1;
while(1)
{
EA=0;
if(stop==0)
{
for(a=0;a<5;a++)
for(b=0;b<102;b++){}
if(stop==0)
disp_1(phil);
//
break;
}
EA=1;
}
}