..>直流電子負(fù)載一、根本要求〔1〕負(fù)載工作模式：恒壓(CV)、恒流(CC)兩種模式可選擇?！?〕電壓設(shè)置及讀出范圍：1.00V～20.0V?！?〕電流設(shè)置及讀出范圍：100mA～3.00A?！?〕顯示分辨力及誤差：至少具有三位數(shù)，相對誤差小于5%。二、總體方案論證與設(shè)計顯顯示按鍵輸入單片機(jī)AD轉(zhuǎn)換ＤＡ轉(zhuǎn)換電流檢測電壓檢測恒壓恒流利用A/D轉(zhuǎn)換把模擬信號轉(zhuǎn)換為數(shù)字信號，在利用單片機(jī)程控來修改電壓電流參數(shù)，此方案準(zhǔn)確度高，操作技術(shù)要求很高，節(jié)省時間。并且用ＤＡ采集顯示測量值，比較得出結(jié)論。1．定電流模式〔CCmode〕在定電流工作模式時，電子負(fù)載所流入的負(fù)載電流依據(jù)所設(shè)定的電流值而保持恒定，與輸入電壓大小無關(guān)，即負(fù)載電流保持?jǐn)z定值不變。２．定電壓模式〔CVmode〕在定電壓工作模式時，電子負(fù)載所流入的負(fù)載電流依據(jù)所設(shè)定的負(fù)載電壓而定，此時負(fù)載電流將會增加直到負(fù)載電壓等于設(shè)定值為止，即負(fù)載電壓保持設(shè)定值不變。電源模塊根本電路圖單片機(jī)模塊根本電路三、測試及分析測試原始數(shù)據(jù)１.恒流模式數(shù)據(jù)測量模式設(shè)定值〔A〕測量值1(A)測量值2(A)測量值3(A)工作電壓(V)工作電壓(V)工作電壓(V)恒流恒流恒流恒流恒流２.恒壓模式數(shù)據(jù)測量模式設(shè)定值(V)測量值1(V)測量值2(V)測量值3(V)工作電壓(V)工作電壓(V)工作電壓(V)恒壓恒壓3.163.083.14恒壓8.969.04恒壓15.24恒壓19.8421.12四、附錄根本程序恒流模塊#include<reg52.h>#include<intrins.h>#defineuintunsignedint#defineucharunsignedcharsbitrs=P2^7;sbitE=P2^6;sbitadwr=P2^5;sbitadrd=P2^4;floatadval;longinttemp;voiddelay(uintz)//延時子程序{uint*,y;for(*=z;*>0;*--)for(y=110;y>0;y--);}write_(uchar)//寫命令{rs=0;P0=;delay(5);E=1;delay(5);E=0;}write_data(uchardat)//寫數(shù)據(jù){rs=1;P0=dat;delay(5);E=1;delay(5);E=0;}init()//液晶初始化{E=0;write_(0*38);write_(0*0c);write_(0*06);write_(0*01);write_(0*80+3);}voidDisplay_Resulti(uchardac)//恒流設(shè)定值子程序{floatdb=0.0; ucharshi=0,ge=0,*s=0,**s=0;P3=dac; db=dac*3.00/158.00; shi=(int)db/10; ge=(int)db%10; db*=10.0;*s=(int)db%10; db*=10.0;**s=(int)db%10;write_(0*80+1);delay(2);write_data('c');delay(2);write_data('u');delay(2);write_data('r');delay(2);write_data('r');delay(2);write_data('e');delay(2);write_data('n');delay(2);write_data('t');delay(2);write_data(0*3a);delay(2);if(shi==0){write_data(0*20);delay(2);}elsewrite_data(0*30+shi);delay(2);write_data(0*30+ge);delay(2);write_data(0*2e);delay(2);write_data(0*30+*s);delay(2);write_data(0*30+**s);delay(2);}voidDisplay_Resulti1(floatadval)//測量電流值子程序{ucharge,*s,shi,**s;temp=(longint)(adval*105/51);shi=temp/1000;ge=temp/100%10;*s=temp/10%10;**s=temp%10;write_(0*80+0*40+1);delay(2);write_data('C');delay(2);write_data('U');delay(2);write_data('R');delay(2);write_data('R');delay(2);write_data('E');delay(2);write_data('N');delay(2);write_data('T');delay(2);write_data(0*3a);delay(2);if(shi==0){write_data(0*20);delay(2);}elsewrite_data(0*30+shi);delay(2);write_data(0*30+ge);delay(2);write_data(0*2e);delay(2);write_data(0*30+*s);delay(2);write_data(0*30+**s);delay(2);}voidADC()//啟動AD轉(zhuǎn)換{adwr=1;_nop_();adwr=0;_nop_();adwr=1;P1=0*ff;adrd=1;_nop_();adrd=0;_nop_();adval=P1;adrd=1;}voidmain()//主程序{init();TMOD=0*02;//定時器初始化 TH0=0*6f; TL0=0*00; IE=0*82; TR0=1;while(1)//顯示模塊{ucharkey=0; bitkeyflag=1; uintdac=0; Display_Resulti(dac);while(1)//鍵盤掃描控制顯示 {Display_Resulti1(adval);ADC(); key=P2&0*0f;switch(key) { case0*0e: if(keyflag){ dac=0; Display_Resulti(dac);keyflag=0; } break;case0*0d: if(keyflag){dac+=10; Display_Resulti(dac); keyflag=0; } break;case0*0b: if(keyflag){dac-=10; Display_Resulti(dac); keyflag=0; } break;case0*07: if(keyflag){ dac=158; Display_Resulti(dac);keyflag=0; } break;case0*0f:keyflag=1;break; } }}}恒壓模塊#include<reg52.h>#include<intrins.h>#defineuintunsignedint#defineucharunsignedcharsbitrs=P2^7;sbitE=P2^6;sbitadwr=P2^5;sbitadrd=P2^4;floatadval;longinttemp;voiddelay(uintz)//延時子程序{uint*,y;for(*=z;*>0;*--)for(y=110;y>0;y--);}write_(uchar)//寫命令{rs=0;P0=;delay(5);E=1;delay(5);E=0;}write_data(uchardat)//寫數(shù)據(jù){rs=1;P0=dat;delay(5);E=1;delay(5);E=0;}init()//液晶初始化{E=0;write_(0*38);write_(0*0c);write_(0*06);write_(0*01);write_(0*80+3);}voidDisplay_Resultu1(floatadval)//恒壓設(shè)定值子程序{ucharge,*s,shi,**s;temp=(longint)(adval*110/51);temp=temp*4;shi=temp/1000;ge=temp/100%10;*s=temp/10%10;**s=temp%10;write_(0*80+0*40+1);delay(2);write_data('V');delay(2);write_data('O');delay(2);write_data('L');delay(2);write_data('T');delay(2);write_data('A');delay(2);write_data('G');delay(2);write_data('E');delay(2);write_data(0*3a);delay(2);if(shi==0){write_data(0*20);delay(2);}elsewrite_data(0*30+shi);delay(2);write_data(0*30+ge);delay(2);write_data(0*2e);delay(2);write_data(0*30+*s);delay(2);write_data(0*30+**s);delay(2);}voidDisplay_Resultu(uchardac)//測量電壓子程序{floatdb=0.0; ucharshi=0,ge=0,*s=0,**s=0;P3=dac; db=dac*20.00/255.00; shi=(int)db/10; ge=(int)db%10; db*=10.0;*s=(int)db%10; db*=10.0;**s=(int)db%10;write_(0*80+1);delay(2);write_data('v');delay(2);write_data('o');delay(2);write_data('l');delay(2);write_data('t');delay(2);write_data('a');delay(2);write_data('g');delay(2);write_data('e');delay(2);write_data(0*3a);delay(2);if(shi==0){write_data(0*20);delay(2);}elsewrite_data(0*30+shi);delay(2);write_data(0*30+ge);delay(2);write_data(0*2e);delay(2);write_data(0*30+*s);delay(2);write_data(0*30+*s);delay(2);}voidADC()//啟動AD轉(zhuǎn)換{adwr=1;_nop_();adwr=0;_nop_();adwr=1;P1=0*ff;adrd=1;_nop_();adrd=0;_nop_();adval=P1;adrd=1;}voidmain()//主程序{init();TMOD=0*02;//定時器初始化 TH0=0*6f; TL0=0*00; IE=0*82; TR0=1;while(1)//顯示模塊{ucharkey=0; bitkeyflag=1; uintdac=0; Display_Resultu