1.本系统采用STC89C52作为单片机
2.采用液晶LCD1602液晶实时显示相关数据
3.采用矩阵键盘可设置PID相关参数
4.采用L298驱动功率电阻模拟加热过程
5.当温度超过设定值的一定范围启动声光报警系统
6.DC002直接5V电源输入
7.支持按键和旋钮两种温度设定模式，设定范围30~80℃；通过滑动变阻器旋钮可无极设置温度值
8.采用NTC电阻实时测量温度变化
原理图：
PCB：
主程序：
#include "reg51.h"#include "math.h"#define uchar unsigned char#define uint unsigned int#define ulong unsigned long#define T25 (273.15+25) //T25#define Bx (4050.0) //B值#define Ka (273.15) //绝对零度#define Rp (10000.0) //ntc串联电阻#define ntcR25 (10000.0) //25度时电阻//#define RA (0.00335)//#define RB (0.000259)//#define RC (0.00000305)//#define RD (-0.000000272)//#define RE (-0.0000000648)/*****************引脚定义*********************************/// l298nsbit RELAY_HEAT = P1^4;sbit RELAY_COOL = P1^5;sbit ENA = P1^6;/********************************/// AD芯片sbit CLOCK = P1^0;sbit D_IN = P1^1;sbit D_OUT = P1^2;sbit _CS = P1^3;/********************************/// lcd液晶sbit LCD_RS = P3^5;sbit LCD_EN = P3^6;/********************************///蜂鸣器sbit SPEAKER = P3^7;/*****************变量定义（声明）*********************************/int freq = 500, pwm = 0;uchar setflag = 0, pageflag = 0, ok = 0;float set_temp = 0;float KP = 10, KI = 1, KD = 0;uint pul_count = 0;float ek = 0, ek1 = 0, ek2 = 0;float keytemp = 0;uchar code str[16] = " welcome! ";uchar code str1[16] = " temperature PID";uchar code str2[16] = "set-Tnow-T ";uchar code str3[16] = "P:I:D:";uchar code str4[16] = "set-P: ";uchar code str5[16] = "set-I: ";uchar code str6[16] = "set-D: ";void Init(void);uint adcread(uchar port);float ReadTemp(void);void delay(uint n);void writecom(uchar com);void writedata(uchar date);void initlcd();float keyscan(void);//uchar keyscans(void);void lcdnumdisplay(uchar pos, double f);void lcdnumdisplays(uchar pos, double f);//uint read_pul();void mypid(float Kp, float Ki, float Kd, uint count, uint point);void main(){uchar i;float scantemp;float adnum0 = 0;float adnum1 = 0;bit init0, init1, init2, init3, init4;Init();initlcd();writecom(0x80);for (i = 0; i < 16; i++)writedata(str[i]); // huanyinwritecom(0x80 + 0x40);for (i = 0; i < 16; i++)writedata(str1[i]); // shumingdelay(2000);ENA = 1;//RELAY_HEAT=1;RELAY_COOL=0;//while(1);while (1){set_temp = 460 * (float)(adnum0) / 4095;// pwm=set_temp;mypid(KP, KI, KD, adnum1, set_temp);scantemp = keyscan();if (adnum1 >= set_temp - 1.5 && adnum1 <= set_temp + 1.5){SPEAKER = 1;}else{SPEAKER = 0;}if (setflag == 0){adnum0 = adcread(1);adnum1 = ReadTemp();if (init0 == 0){initlcd();writecom(0x80);for (i = 0; i < 16; i++)writedata(str2[i]); // shuminginit0 = 1;init1 = 0;init2 = 0;init3 = 0;init4 = 0;}lcdnumdisplays(0x80 + 0x40, (float)set_temp); // set_templcdnumdisplays(0x80 + 0x4a, (float)adnum1);}if (setflag != 0 && pageflag == 0){if (init1 == 0){initlcd();writecom(0x80);for (i = 0; i < 16; i++)writedata(str3[i]);init0 = 0;init1 = 1;init2 = 0;init3 = 0;init4 = 0;}lcdnumdisplays(0x80 + 0x40, KP);lcdnumdisplays(0x80 + 0x46, KI);lcdnumdisplays(0x80 + 0x4D, KD);}if (setflag != 0 && pageflag == 1){if (init2 == 0){initlcd();writecom(0x80);for (i = 0; i < 16; i++)writedata(str4[i]);init0 = 0;init1 = 0;init2 = 1;init3 = 0;init4 = 0;}lcdnumdisplays(0x80 + 0x40, scantemp);if (ok == 1){KP = scantemp;ok = 0;}}if (setflag != 0 && pageflag == 2){if (init3 == 0){initlcd();writecom(0x80);for (i = 0; i < 16; i++)writedata(str5[i]);init0 = 0;init1 = 0;init2 = 0;init3 = 1;init4 = 0;}lcdnumdisplays(0x80 + 0x40, scantemp);if (ok == 1){KI = scantemp;ok = 0;}}if (setflag != 0 && pageflag == 3){if (init4 == 0){initlcd();writecom(0x80);for (i = 0; i < 16; i++)writedata(str6[i]);init0 = 0;init1 = 0;init2 = 0;init3 = 0;init4 = 1;}lcdnumdisplays(0x80 + 0x40, scantemp);if (ok == 1){KD = scantemp;ok = 0;}}}}float ReadTemp(void){float current = 0;float Rt = 0;float f_tempVolt = 0; //温度对应电压float f_temp = 0;f_tempVolt = 5 * (float)adcread(0) / 4096; //读取电压current = (5 - f_tempVolt) / Rp; //计算电流值Rt = f_tempVolt / current; //计算电阻值f_temp = ((Bx * T25) / (T25 * (log(Rt) - log(ntcR25)) + Bx)) - Ka;delay(5);return f_temp;}void mypid(float Kp, float Ki, float Kd, uint count, uint point){static float Uk;ek = point - count;// if(ek>=5&&ek<=-5) //积分分离{Uk = Kp * (ek - ek1) + Ki * ek + Kd * (ek - 2 * ek1 + ek2);}// else// Uk=Kp*ek;pwm = Uk;// lcdnumdisplays(0x80+0x4a,(float)pwm);if (pwm > freq)pwm = freq;if (pwm <= 0){pwm = 0;RELAY_HEAT = 0;RELAY_COOL = 1;}if (pwm > 0){RELAY_HEAT = 1;RELAY_COOL = 0;}ek2 = ek1;ek1 = ek;}//uint read_pul()//{//uint t1, th1, th2;//uint val;//while (1)//{//th1 = TH1;//t1 = TL1;//th2 = TH1;//if (th1 == th2)//break;//}//val = th1 * 256 + t1;//return val;//}void delay(uint n){uint i, j;for (i = n; i > 0; i--)for (j = 1; j > 0; j--);}void Init(void) //初始化函数{TMOD = 0x51;TH0 = (65536 - 10) / 256;TL0 = (65536 - 10) % 256;EA = 1;ET0 = 1;TR0 = 1;TH1 = 0;TL1 = 0;TR1 = 1;}
仿真演示视频：
/video/BV1me4y187np/
实物演示视频：
/video/BV1rG4y1z7yc/
