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BI TP LNO LNG QU TRNH TI:HIN TH NHIT TRN LED 7 ON S DNG CM BIN LM335

GVHD: Ths Nguyn Th Phng ThoSVTH:1. Phm Minh Khi-411041812. H Vn Tin-411042653. Nguyn Vn Pht 411042214. Phng Tr Hiu-411041495. Vi Vn Dng-41104127

LI NI U

o lng qu trnh l mn hc l thuyt mang tnh thc t tuy nhin th hiu v bit c tp th nhm chng em c c dn dt v thc hin mt bi tp ln mang tnh thc t v gip chng em d hiu bi. Trong vic hc l thuyt ngoi ngun kin thc m c b tr trn lp th bi tp ln ni cch khc l mt phng php gip chng em tin gn hn v hiu su hn v bi hc. hon thnh ti ny mt cch thnh cng v tt p chng em xin chn thnh gi li cm n su sc n c to dng mi trng tt em c iu kin tip xc thc t.

Mc LcLI NI U2Phn 1: S LC V CM BIN S DNG LM3354I.c im cu to:4II.Nguyn L Hot ng:4III.Phn loi :5Phn 2: Cc Linh Kin S Dng Trong Mch Thit K8I.Pic16F877A:8II.Thch anh:8III.in Tr:8IV.Transistor 2N3702:8V.LM3359VI.Led 7 on:9Phn 3: Thi Cng Thit K10I.Mch m phng Protues:10II.Code khi to:11Phn 4: Mch Sau Khi Thit K V Chy Thc T16I.Mch in:16Phn 6: nh Gi Kt Qu17Phn 7: nh Gi Ca Ging Vin18

Phn 1: S LC V CM BIN S DNG LM335

I. c im cu to:N c 3 chn chnh : 2 chn cp ngun v 1 chn out tn hiu Analog. Khi ta cp in p 5V cho LM335 th nhit o c t cm bin s chuyn thnh in p tng ng ti chn s 2 (Vout). in p ny c t l vi gii nhit m n o c. Vi gii ca nhit u ra l 10mV/K. Hot ng trong gii in p t 0 cho n 5V v gii nhit o c t 00C n 1000C . V cn ch n nhng thng s chnh sau : + Hot ng chnh xc dng in u vo t 0.4mA n 5mA. Dng in u vo ngoi khong ny kt qu o s sai .+ in p cp vo n nh l 5V .+ Tr khng u ra thp 1 m .+ Gii nhit mi trng l t 0 n 100 C Nh vy LM335 n cho chng ta tn hiu tng t (Analog) v chng phi x l tn hiu ny thnh nhit .

II. Nguyn L Hot ng:Nhit t mi trng s c cm bin hp thu, ti y ty theo c cu ca cm bin s bin i lng nhit ny thnh mt i lng in no (in p, dng in). Nh th mt yu t rt quan trng l Nhit mi trng cn o v Nhit cm nhn ca cm bin. C th iu ny l: Cc loi cm bin m ta trng thy n u l ci v bo v, phn t cm bin nm bn trong ci v ny (bn dn, lng kim). Do vic o c chnh xc hay khng ty thuc vo vic truyn nhit t mi trng vo n phn t cm bin tn tht bao nhiu.(1 trong nhng yu t quyt nh nh gi cm bin nhit)

III. Phn loi :

Cp nhit in (Thermocouple)

Nhit in tr (RTD-resitance temperature detector)

Thermistor

Bn dn (Diode,IC,)IC cm bin nhit Microchip TC74A0-5.0 VATDS18B20 Cm bin nhit

Tnh ton cc gi tr ca mch o:Do tn hiu tr v t cm bin LM335 l tn hiu tng t. Nh vy x l tn hiu ny v cho ra kt qu tng ng th ta cn dng b bin i tng t sang s gi tt l ADC. u bi l o nhit mi trng nn ta chn gi tr cao nht v thp nht l 0 n 1000C.Nh ta bit phn gii nhit ca LM335 l 10mV/K nn ta c: Ti 00C th in p u ra ti LM335 l 2.73V Ti 1000C th in p u ta ti LM335 l 3.73VNh vy gii in p n ADC bin i l t 2.73V n 3.73V tc l 1VGi S l gii in p o ca tn hiu: S= 3.73 - 2.73 =1VA l gii in p ca ADC : A = 5VTa c trong con Dspic tch hp sn b khi ADC 10bit tc cao v trong con Psoc n cng tch hp sn b ADC 11bit nn s dng b ADC ny cho mc ch bin i. Ta c bc thay i ca ADC 10 bit:N = 5/1024 = 4.9mV (Dspic)N1=5/2047 = 2.44mV (Psoc) Tnh gi tr nhit u raLM335 l cm bin nhit , vi nhit u ra l 10mV/KS dng b bin i ADC_10 bit: C gi tr ln nht l 1024 Vi V = 5V Bc thay i l 4.9mV (Dspic) v 2.44mV (Psoc) 00C hay 2730K thi in p u ra LM335 c gi tr l 2.73V 1000C hay 3730K th in p u ra ca LM335 c gi tr l 3.73VNh vy gii in p u vo s l 2.73 n 3.73V

Phn 2: Cc Linh Kin S Dng Trong Mch Thit K

I. Pic16F877A:

II. Thch anh:

III. in Tr:Tr 4k7, 1k5, 470 OhmIV. Transistor 2N3702:

V. LM335

VI. Led 7 on:

Phn 3: Thi Cng Thit K

I. Mch m phng Protues:

II. Code khi to:

#include #include #device *=16 adc=10#FUSES NOWDT, HS, NOPUT, NOPROTECT, NODEBUG, NOBROWNOUT,NOLVP, NOCPD, NOWRT#use delay(clock=20000000)#define speak PIN_A1#use fast_io(d)#byte portd=0x8int8 low,high,min,max,i,j,low1,high1;int1 do_F;void convert_bcd(int8 x);const char led7seg[12]={0xC0,0xcf,0xa4,0xb0,0x99,0x92,0x83,0xf8,0x80,0x90,0x8e,0xc6};const char quet[3]={0x01,0x02,0x04};#INT_EXTvoid test() { if (do_F == 1) do_F=0; else do_F=1; }void main() { float value; min =15; //nhiet do min max =35; //nhiet do max do_F =0 ; i = 10 ; set_tris_d(0); trisa = 0xFF; trisb = 0x01; trisc=0x00; portd=0xff; output_low(speak); enable_interrupts (INT_EXT); ext_int_edge(H_TO_L); enable_interrupts (GLOBAL); setup_adc_ports(AN0); setup_adc(ADC_CLOCK_INTERNAL); delay_us(10);// Lay mau nhiet do lan dau tien value=(float)read_adc(); value = (value - 558.5)/2.048; // For 5V supply // value = (value - 754.8)/2.048; // For 3.7V Supply // value = (value - 698.2)/2.048; // For 4V supply convert_bcd((int8)value); // Tach so tram, chuc, donvi de hien thi len LED 7 delay_ms(500); while(1) { if (i==10) { value = read_adc(); value=(value-558.5)/2.048; if (do_F==1) value=1.8*value+32; convert_bcd((int8)value);

if (do_F==0) { for(j=0;jADC_value = (1024/5).2.73 = 559 (Dspic) + V_in = 3.73V => ADC_value = (1024/5).3.73 = 764 (Dspic) + V_in = 2.73V => ADC_value = (2047/5)*2.73 = 1118 (Psoc) + V_in = 3.73 => ADC_value = (2047/5)*3.73 = 1527 (Psoc) Mt khc do ADC_value = 1 cho ra in p tng ng l 4.9mV (dspic) v 2.44mV (Psoc). Trong khi LM335 cho ra in p l 10mV/K. Nn do ADC _value thay i trong 1 n v th nhit phi thay i l : (4.9mV/10mV/K) = 0.5K (dspic) v (2.44mV/10mV/K) = 0.244K (Psoc) Nh vy ta c cng thc tnh y ra C tng ng cho c Psoc v Dspic: t = (ADC_value 559)* (4.9mV/10mV) = (ADC_value 559) * 0.49 (i vi Dspic) t = (ADC_value - 1118) * (2.44mV/10mV) = (ADC_value - 1118) * 0.244 (i vi Psoc) 5) Tnh gi tr in tr m cho LM355 Mun p ra ng vi 10mV/oK th phi cp dng cho n t 400uA n 5mA, vy phi c in trNu dng ngun p 5V, di o t 0-100 C => p trn LM335 s t 2.73V n 3.73V => p ri trn in tr s l t 2.27V n 1.27V => chn in tr 1.5k ni 5V - 1,5k - LM335. Do in tr 1.5K khng c nn ta dng bin tr cho in tr m l 1.5K.iu chnh gitr123doc.vnnaTnh ton cc gi tr ca mch o Do tn hiu tr v t cm bin LM335 l tn hiu tng t . Nh vy x l tn hiu ny v cho ra kt qu nhit tng ng th ta cn dng b bin i tng t sang s gi tt l ADC. u bi l o nhit t 0 n 100 C Nh ta bit phn gii nhit ca LM335 l 10mV/ K nn ta c + Ti 0 C th in p u ra ti LM335 l 2.73V + Ti 100 C th in p u ra LM335 l 3.73V Nh vy gii in p m ADC bin i l t (2.73V n 3.73V) tc l 1V Gi S l gii in p o ca tn hiu : S = (2.73 3.73V) tc l 1V A l gii in p ca ADC : A = 5V Ta c trong con Dspic tch hp sn b khi ADC 10 bit tc cao v trong con Psoc n cng tch hp sn b ADC 11 bit nn s dng b ADC ny cho mc ch bin i. Ta c bc thay tTnh ton cc gi tr ca mch o Do tn hiu tr v t cm bin LM335 l tn hiu tng t . Nh vy x l tn hiu ny v cho ra kt qu nhit tng ng th ta cn dng b bin i tng t sang s gi tt l ADC. u bi l o nhit t 0 n 100 C Nh ta bit phn gii nhit ca LM335 l 10mV/ K nn ta c + Ti 0 C th in p u ra ti LM335 l 2.73V + Ti 100 C th in p u ra LM335 l 3.73V Nh vy gii in p m ADC bin i l t (2.73V n 3.73V) tc l 1V Gi S l gii in p o ca tn hiu : S = (2.73 3.73V) tc l 1V A l gii in p ca ADC : A = 5V Ta c trong con Dspic tch hp sn b khi ADC 10 bit tc cao v trong con Psoc n cng tch hp sn b ADC 11 bit nn s dng b ADC ny cho mc ch bin i. Ta c bc thay 10