bao_cao_KejP8_20130617105513_19

TRNG I HC K THUT CNG NGHIP THI NGUYN

TRNG I HC K THUT CNG NGHIP

KHOA IN T

B MN: K THUT MY TNH N MN HC

MN HC

H THNG NHNG

Nhm sinh vin : Li Vn Hi

Dng Th L

inh Vn on

Lp : K43K

Gio vin hng dn : Ths.Nguyn Vn Huy

Thi Nguyn 2011

Nhn xt ca gio hng dn

Thi Nguyn, Ngy Thng Nm 2011

Gio Vin hng dn

(K ghi r h tn)

Nhn xt ca gio vin chm

Thi Nguyn, Ngy Thng Nm 2011

Gio Vin chm

(K ghi r h tn)

MC LC3Li ni u

CHNG 1 . PHN TCH BI TON.41.1.Kho st v phn tch bi ton..41.1.1. t vn ...41.1.2. Gii thiu bi ton.41.1.3. Mc ch.....51.1.4. Cc cng ngh sn phm hinc mt trn th trng...61.2. La chn gii php 81.2.1.Gii php cng ngh..81.2.2 .Gii php thit k..91.2.3.Cc yu cu101.2.4.Gii hn cho h thng..10CHNG 2: THIT K H THNG.122.1. S tng qut 122.2. S c t h thng..132.3. S Call graph...142.4. S nguyn l mch..152.5.Cc module trong h thng...182.5.1.Module iu khin trung tm.182.5.2.Module hin th.192.5.3.Module o p sut.202.5.4.Module khi ngun..212.5.5.Module khi giao tip bn phm.222.6. S thut ton h thng232.7. Nguyn l hot ng242.8.La chn cc linh kin..252.8.1. Khi vi iu khin252.8.2. Khi hin th.422.8.3. Khi o p sut....482.8.4. Khi bn phm.522.8.5. Khi ngun..532.8.6. Cc loi linh kin khc54CHNG 3. XY DNG H THNG...563.1.Xy dng phn cng563.2.Xy dng phn mm60

Li ni u Ngy nay, cc h thng nhng tr nn ph bin v ng vai tr quan trng trong i sng con ngi. V d quanh ta c rt nhiu sn phm nhng nh l vi sng, ni cm in, iu ha, in thoi di ng, t, my bay, tu thy, cc u o, c cu chp hnh thng minh, robot v.v... ta c th thy hin nay h thng nhng c mt mi lc mi ni trong cuc sng ca chng ta.

Qua mn hc h thng nhng , chng em hiu thm v cc h thng nhng trong thc t, v c im, tnh u vit cng nh tnh ng dng ca chng i vi con ngi. Vi mong mun lm r cc kin thc hc v gii thiu cc ng dng c bn ca h thng nhng, nhm chng em a ra m hnh thit k h thng o v cnh bo p sut. Mt sn phm rt quen thuc v cn thit trong i sng.

Do thi gian thc hin v kin thc cn hn ch nn cn nhiu sai st trong qu trnh thc hin ti, rt mong c s b sung ng gp ca cc thy c v cc bn.

Chng em xin chn thnh cm n cc thy c trong khoa in t b mn k thut my tnh, cm n thy Ths. Nguyn Vn Huy tn tnh hng dn v gip chng em thc hin hon thnh ti ny.Trn trng v chn thnh cm n!

Nhm thc hin ti:

Li Vn Hi

Dng Th L

inh Vn onCHNG 1.PHN TCH BI TON

1.1. Kho St V Phn Tch H Thng.1.1.1. t vn .

Ngy nay cng vi s pht trin ca cc ngnh khoa hc k thut, k thut in t m trong l k thut s ng vai tr quan trng trong mi lnh vc khoa hc k thut, qun l, cng nghip t ng ha, cung cp thng tin. do chng ta phi nm bt v vn dng n mt cch c hiu qu nhm gp phn vo s pht trin nn khoa hc k thut th gii ni chung v trong s pht trin k thut in t ni ring.

Xut pht t mn hc h thng nhng ca b mn k thut my tnh, chng em c nghin cu v cu to v nguyn l hot ng ca cc vi iu khin nh: b vi iu khin 8051, hay cc loi Pic...nh chng em nghin cu lm m hnh mch v cnh bo p sut vi cc chc nng nh o p sut v a ra cnh bo khi p sut mc cao hoc thp hn mc cho php ng dng vo cc h thng iu khin t ng.

T nhng iu c thy v kh nng ca chng em, chng em mun lm mt iu g nh gp phn vo vic gip cho s an ton ca ngi lao ng cng nh gim bt c phn no v s thit hi v kinh t cho cc nh my x nghip. Nn chng em quyt nh thit k ra m hnh ny. N rt c ngha i vi chng em v lm c mt phn nh cho h thng bo ng trong cc nh my x nghip1.1.2. Gii thiu bi ton. H thng cnh bo p sut l h thng m khi p sut tng qu cao hay vt qu mt ngng cho php no th h thng s pht ra mt tn hiu cnh bo (c th bng ci,n,m thanh) c tc dng bo ng khi xy ra s c.

H thng cnh bo p sut dng :.

o v hin th p sut ca mi trng mt thi im bt k trong khong t Pmin n Pmax no .

Bo ng khi p sut ca mi trng trong mt khong no m ta chn. Hin nay nhu cu s dng h thng ny l rt ln, h thng c ng dng rt nhiu trong thc t nh : H thng c s dng trong vic o v cnh bo p sut cho mt nh my, mt x nghip gim st o p sut ca cc l nung, trong cc ng ng ca cc nh my, lp oto1.1.3. Mc ch. o ap sut la mt trong nhng chc nng o c ban nht trong bt c nganh cng nghip nao. T mt nha may loc du n mt chic xe ui t, vic o ap sut khi nen, lu cht thuy lc, cht long trong cac quy trinh, hi nc hoc v s cac mi trng trung gian khac la chuyn xay ra hang ngay va ong vai tro then cht i vi tt ca cac cach thc iu khin. Kt qua la, u ta cung bt gp cac thit bi o ap sut, va co v s cac la chon. V vy vic chng em mun thit k ta h thng o v cnh bo p sut dng o p sut, a ra cnh bo t chng ta c th bit c p sut nhng ni m chng ta cn o v c th a ra cc bin php khc phc 1.1.4. Cc sn phm hin c bn trn th trng:

a, Thit b kim sot p sut v nhit bnh xe: Sn phm cng ngh cao RoadSnoop l ca hng sn xut lp xe Nokian (Phn Lan). B dng c gm 4 u o c gn mt ngoi cc vnh bnh xe (trong lng lp) v mt hin th thng tin t trong salon. Phn t o truyn tn hiu vo ca-bin thng qua sng radio. Khi p sut hi trong bnh xe st gim hoc nhit lp cao ti mc bo ng, u o s gi sng cnh bo n thit b hin th ng b trong salon hoc inthoi i ng trong xe (nu c ci t tip nhn song ny).

Khi p sut hi trong bnh xe st gim hoc nhit lp cao ti mc bo ng, u o s gi sng cnh bo n thit b hin th ng b trong salon hoc in thoi i ng trong xe (nu c ci t tip nhn sng ny). Trong cc ci tin tip theo, h thng c th thc hin chc nng kim sot ton b thng s ca bnh xe, mn lp v xc nh v tr chnh xc ca n trn mt ng. Nhng thng tin ny h tr li xe rt nhiu trong vic trnh hng hc v tai nn. Thit b s dng pin xc vi h thng chuyn i v tch in t ng nng ca bnh xe. Nh sn xut m bo rng thit b ny c th ng hnh cng chic xe qua 150.000 km hay 10 nm, vi iu kin xe khng nm yn trong ga-ra.

u im:

H thng cnh bo p sut lp xe cho ta bit c tnh trng v p sut cng nh mc an ton v lp xe khi s dng xe.v t ta c th a ra phng php khc phc hiu chnh ph hp vi yu cu ca ngi s dng.

Nhc im:

Do cc cm bin c lp trn c 4 bnh ca xe v cc cm bin ny phi tng thch vi nhau nn khi thay lp ta cn phi thay lp c cm bin tng thch vi cm bin ca lp. Sau khi thay lp mi chng ta cn phi khi ng li h thng th my tnh mi nhn ra c v tr ca lp mi. b, thit b o p sut ng ng trong cc nh my. Cc thit b o p sut ng ng trong cc nh my c rt nhiu loi nh: testo 511, 512, 556, 560,.

Testo 521

Theo di dy chuyn sn xut

Thit b dng vi cm bin bn trong. Dng o v gi, st p sut cc h thng thng gi, cc ng ng

u im: gn nh, tin li v d s dng

Nhc im: gi thnh cao, 1.2. La Chn Gii Php

1.2.1. Gii php cng ngh:

Vi mc ch ca nhm chng em l thit k ra h thng o v a ra cnh bo p sut ca cc ng ng trong cc nh my x nghip khi m p sut vt qu hay thp hn mc cho php. Cng vi l mc ca p sut c o v hin th trn mn hnh LCD. Gii hn o ca h thng o p sut m nhm chng em thit k l c kh nng o c p sut nm trong khong t 15Kpa n 115Kpa. V p sut sau khi o s c hin th trn mn hnh LCD, a ra cnh bo trn chung v LED.1.2.2. Gii php thit k.

Vic la chn gii php thng c xem xt trn nhiu phng din nhng quan trng l gii php c kh thi khng? C ph hp vi vi thc t v tha mn yu cu v kinh t? Qua tm hiu, tham kho mt s ti liu trn internet, nhm chng em quyt nh la chn b vi iu khin PIC16F877A, cm bin p sut MPX4115 bi n p ng tt nht cc yu cu ca ti. C th l: Cc thit b ny c sn trn th trng , gi thnh r, m bo tin cy lm vic, chnh xc, tnh lin tc khi lm vic, p ng c cng sut tinh ton C sn cc cng c pht trin phn mm chng hn nh trnh bin dch trnh hp ng v g ri. Ngun cc b vi x l co sn nhiu v tin cy. lm c mch ny nhm chng em thit k ra gm 4 phn chnh sau:

B phn iu chnh : gm c cc phm iu khin

B phn vi iu khin

Sensor

B phn hin th

B phn cc phm iu chnh:

phm iu chnh n nh gim p sut

phm iu chnh t ng tng p sut

B phn hin th gm:

Mn hnh LCD hin th p sut

Cc Led bo trng thi ca p sut

B phn vi iu khin

Vi iu khin

Khi ngun nui(s dng ngun 5v)

Khi dao ng (s dng thch anh)

H thng chung cnh bo.

H thng o v cnh bo p sut vi b no VK 18F77A v cc linh kin khc: LCD hin th, IC n p7805, cm bin p sut MPX4115.

Pic 18F77A c cc u im: tnh nng v tc p ng c yu cu k thut trong ng dng khng i hi cao;gi thnh thp. C h tr lp trnh iu khin bng c hp ng v C...

Cm bin MPX4115 l cm bin chuyn dng, cho kh nng o chnh xc v p sut.

LCD hin th mt cch r rng.

IC n p 7805 c s dng rng ri trong cc b ngun. V vy gii php thit k h thng o v cnh bo p sut dng cc linh kin trn c rt nhiu u th. ng thi m bo c yu cu v kinh t.

Trong thc t hin nay h thng o v cnh bo p sut l mt sn phm rt gn gi vi mi ngi, c s dng rt rng ri.1.2.3. Cc yu cu Vi sn phm o v cnh bo p sut i hi cc yu cu:

Hin th ng gi tr p sut trong mi trng cn o. iu chnh v thay i c ngng cnh bo. m bo ng c th hot ng ngay c khi mt in(nh ngun nui ph). Kh nng thc thi: Thi gian p ng, chnh xc m bo v kch thc v trng lng cho php. an ton, kh nng chng li s ph hoi hay xm nhp1.2.4. Gii hn cho h thng. S dng ngun in 5V.

Lm vic lin tc. Kch thc ph hp vi ngi s dng. H thng nh gn. H thng c kh nng lm vic khi mt ngun cp (c ngun d tr). Chi ph cho h thng khng qu 600.000. Vi thi gian s dng c th s dng c trong khong 10 nm.CHNG 2: THIT K H THNG

2.1. S M Hnh Tng Qut Ca H Thng

Hnh 2.1: S tng qut ca h thng Khi cm bin nhn p sut t mi trng bin i thnh in p v a n khi x l trung tm. Khi x l trung tm sau khi nhn c tn hiu t khi cm bin th s tnh ton bin i thnh in p a ra cho khi hin th hin th ln mn hnh v ng thi nu tn hiu sau khi bin i nm trong phm vi cnh bo th khi x l trung tm s gi tn hiu n khi chp hnh. Khi chp hnh sau khi nhn c tn hiu s tc gi bo ng. Khi tng tc iu khin chnh l b bn phm dng iu chnh mc ngng cho php tc ng ca khi chp hnh thng qua khi x l trung tm. Khi ngun cung cp ngun cho b VK v cac khi khc trong s

2.2. S c T H Thng:

Hnh 2.2: S c t h thngVi: + P: l p sut

+min: l p sut ngng thp

+max: l p sut ngng cao2.3. S Call Graph H Thng:

Hnh 2.3: S quan h gia cc module phn cng v phn mm trong h thng cnh bo nhit 2.4. S Nguyn L Mch.

a, s .

Hnh 2.4:S nguyn l mch m phng bng proteus

b, nguyn tc hot ng.

Chn 1 c ni vi mch reset. Khi nhn SW1 th b vi iu khin s c khi ng li t u. Chn 13-14 c ni song song vi thch anh 12Mhz. Mch c nhim v to dao ng cho vi iu khin. T chn RD2 v RD3 ln lt c ni vi RS, E ca LCD. C nhim v iu khin hot ng ca LCD. RD4=>RD7 ln lt c ni vi u vo d liu t D4=> D7 ca LCD. C chc nng iu khin hin th LCD theo nhit o c. Chn 2(VDD) ca LCD c ni vi ngun;chn VSS, RW c ni vi mt.

Hnh 2.5: S chn ca LCD LM016L*Ngyn tc: Khi khi ng h thng, cm bin p sut MPX4115 s bin i u vo l p sut mi trng thnh tn hiu in p. Tn hiu ny c a vo vi iu khin qua chn AN0 (analog ca ADC) ca PIC16f877A; trong pic tch hp sn b chuyn i tng t sang s ( tn hiu in p c chuyn i sang tn hiu s v c xut ra cng t RD4->RD7 v c hin th ln mn hnh LCD. Khi p sut tng qu mt gii hn cho php th pht tn hiu cnh bo lm cho led sng. Cc nt bm : nt 1; nt 2; nt 3; nt 4 cho php ta iu chnh p sut t (p sut cnh bo): Khi ta nhn nt 1 th hin th p sut t ngng cao hin ti v ch cc phm khc c nhn.

Khi ta nhn nt 4 th hin th p sut t ngng thp hin ti.

Khi nt 2 c nhn cho php ta tng p sut t.

Khi nt 3 c nhn cho php ta gim p sut t. Cng thc bin i trong ADC: Ta dng adc ca pic la 10bit ( max= 1023, Vref=Vcc. M p sut bin i trong khong t 15 n 115KPa. Ta c cng thc tnh p sut nh sau:

P=kq*100/1023+15

Kq: l gi tr u ra ca ADC di dng thp phn.2.5. Cc Module Trong H Thng 2.5.1. Module khi iu khin trung tm.

a, s :

Hnh 2.6: khi iu khin trung tmb, nguyn tc hot ng.

Khi iu khin trung tm s dng vi iu khin PIC18F77A, qua chng trnh lp trnh c np cho chip, vi iu khin s iu khin vic c, ghi cc tr s p sut ln khi hin th l LCD.

B dao ng thch anh c tc dng to xung nhp vi tn s 12MHz cho VK hot ng. Hai u ny c ni vo 2chn XTAL1 v XTAL2 ca VK.

B RESET c tc dng a vi iu khin v trng thi ban u. Khi nt Reset c n in p +5V t ngun c ni vo chn Reset ca vi iu khin c chy thng xung t lc ny in p ti chn vi iu khin thay i t ngt v 0, VK nhn bit c s thay i ny v khi ng li trng thi ban u cho h thng.

2.5.2. Module Hin Th.

a, s .

Hnh 2.7: khi hin thb, nguyn tc hot ng.

S dng mn hnh LCD (LM016L) hin th p sut m cm bin o c, LCD s hin th c tt c cc k t trong bng m ASCII. Ta ch c th hin th l mt su k t th hin th c nu l s ch hin th dc tng s v th phi chia cc thnh phn trm, chc n v ca p sut ra ri hin th tng phn. Chn cc chn D4-D7 lm chn nhn d liu ca LCD. Cng D(RD2-RD7) ca VDK lm cng ra a d liu ra LCD. Cc led D1, D2, D3 bo trng thi p sut m cm bin nhn c. D1 sng khi p sut vt qu ngng cao Pmax. D2 sng khi p sut thp hn ngng di Pmin. D3 sng khi p sut nm trong khong tPmin n Pmax. Cc cc dng ca led c ni vi chn RC0-RC2 (l cc cng ra) khi p sut vt qu ngng cao Pmax th VDK a mc logic 1 ra chn RC0 led D1 sng tng t vi cc trng thi cn li.2.5.3. Module o p Sut.

a, s .

Hnh 2.8: khi cm binb, nguyn tc hot ng.

S dng cm bin p sut MPX4115 o p sut. p sut m cm bin o c s c bin i ra thnh in p a vo VK. Thng qua b bin i ADC ca VK th VK s tnh ton ra p sut.2.5.4. Module Khi Ngun. a, s .

Hnh 2.9: s khi ngun b, nguyn tc hot ng.

in p li 220V qua MBA c bin i thnh in p 15V. V thng qua b bin i cu DIODE c bin i thnh ngun 1 chiu (DC) v sau tip tc c bin i thnh in p chun 5V nh IC7805 cung cp ngun cho cm bin. T C c tc dng lc nhiu n nh in p u ra.2.5.5. Module Khi Giao Tip Phm Bm.

a, s .

Hnh 2.10: s khi bn phm

b, nguyn tc hot ng.

Cc nt bm dng d chn ch hot ng ca cm bin. Cc nt bm c a vo cc chn RB0, RB1, RB2, RB3(cc chn ny dng chn mc ngng cho cm bin). Khi mt nt no c bm th trng thi ca chn mc 1 v VDK s chn ch hot ng v sut tn hiu u ra chn ngng cao hay thp cho cm bin. Nt 1 dng chn ngng trn, nt 4 dng chn ngng di v nt 2, 3 dng tng gim cc mc ngng cho cm bin.2.6. S Thut Ton Ca H Thng: ( s .

Hnh 2.11: Lu thut ton chng trnh chnhVi: + LCD: l mn hnh hin th.

S: l sai; : ng2.7. Nguyn L Hot ng.

Sau khi cp ngun khi ng cho h thng th cc gi tr ngng s c khi to v a vo chng trnh chnh.

Lc ny nu nt 1 c n th tc l ta iu chnh ngng cao cho h thng. iu chnh tng gim ngng ta s dng cc nt 2 v nt 3. Nu nt 2 c n th gi tr ngng cao lc ny ang c tng ln. Nu nt 3 c n th gi tr ngng cao s gim xung.

Nu nt 4 c n th tng ng vi qu trnh iu chnh ngng thp. V cng tng t nh vy ta s dng cc nt 2 v 3 tng gim cc gi tr ngng.

Trong qu trnh iu chnh ngng th cc gi tr ngng khi ta iu chnh s c hin th ra mn hnh LCD.

Nu nt 1 v nt 4 u khng c n thi lc ny h thng s thc hin qu trnh o p sut. Nu p sut o c c gi tr cao hn gi tr ngng cao hoc thp hn gi tr ngng thp th h thng s a ra cnh bo v hin th ln mn hnh gi tr p sut m n o c. Nu p sut o c c gi tr nm trong gii hn cho php tc l nm trong khong t (min max) th kt qu o c s cho hin th ra mn hnh LCD.

Sau khi hin th ra LCD th chng trnh li quay tr v chng trnh chnh thc hin li cc bc nh trn.2.8. La Chn Linh Kin.

2.8.1. Khi iu khin. la chn s dng PIC16F877A Trong mn hc k thut vi x l & vi iu khin cng vi mn h thng nhng , chng em c hc th h vi iu khin 8051 l mt h vi iu khin in hnh, ph bin, d s dng v lp trnh, rt ph hp vi sinh vin mi bt u lm quen n lp trnh cho vi iu khin. Tuy nhin, cng trong qu trnh nghin cu v th nghim vi cc chip iu khin thuc h 8051 ( in hnh l 89C51, 89052), em nhn thy n c nhng nhc im c bn sau y : B nh Ram ni c dung lng thp, ch c 128 bytes. iu n gy tr ngi ln khi thc hin cc d n ln vi vi iu khin 8051. khc phc ta phi m rng thm lm hn ch s chn dnh cho cc ng dng ca vi iu khin. S lng cc b giao tip vi ngoi vi c tch hp sn trong 8051 t, khng c cc b ADC, PWM, truyn d liu song song. Khi mun s dng cc chc nng ny, ta phi s dng thm cc IC bn ngoi, gy tn km v kh thc hin v d b nhiu nu khng bit cch chng nhiu tt. Ngoi ra cn mt s hn ch khc nh s lng Timer ca 8051 t, ch c 2 Timer. Chnh iu ny lm cho gii thut khi vit chng trnh gp kh khn. Nhng nhc im cn bn trn ca 8051, chng em quyt nh khng dng vi iu khin ny cho ti iu khin p sut ca mnh. Vi k vng da trn nn tng kin thc tip thu c khi hc vi iu khin 8051, em rt mun t bn thn tm hiu mt h vi iu khin mi mnh hn, y tnh nng hn trc mt l phuc v tt cho n , lun vn, sau na l cho cc d n trong tng lai nu chng em c dp s dng vi iu khin trong d n ca mnh. Trong qu trnh tm kim mt h vi iu khin mi tha yu cu nh chng em trnh by trn. Chng em nhn thy PIC ca hng Microchip l mt la chn l tng. Ch cn xem xt qua cc port v chc nng ca cc port m chng em trnh by mc c, ta cng d dng nhn ra nhng u im vt tri ca vi iu khin ny so vi 8051. Vi iu khin PIC16F877A

a, S chn v s nguyn l ca PIC16F877A S chn

Hnh 2.12: s cc chn ca PIC16F877A + S nguyn l

Hnh 2.13: s nguyn l PIC16F877A

b, Nhn xt

T s chn v s nguyn l trn, ta rt ra cc nhn xt ban u nh sau : PIC16F877A c tt c 40 chn 40 chn trn c chia thnh 5 PORT, 2 chn cp ngun, 2 chn GND, 2 chan thch anh v mt chn dng RESET vi iu khin. 5 port ca PIC16F877A bao gm : PORTB : 8 chn

PORTD : 8 chn

PORTC : 8 chn

PORTA : 6 chn

PORT E : 3 chnc, Khi qut v chc nng ca cc port trong vi iu khin PIC16F877A

PORTA PORTA gm c 6 chn. Cc chn ca PortA, ta lp trnh c th thc hin c chc nng hai chiu : xut d liu t vi iu khin ra ngoi vi v nhp d liu t ngoi vi vo vi iu khin. Vic xut nhp d liu PIC16F877A khc vi h 8051. tt c cc PORT ca PIC16F877A, mi thi im ch thc hin c mt chc nng :xut hoc nhp. chuyn t chc nng ny nhp qua chc nng xut hay ngc li, ta phi x l bng phn mm, khng nh 8051 t hiu lc no l chc nng nhp, lc no l chc nng xut. Trong kin trc phn cng ca PIC16F877A, ngi ta s dng thanh ghi TRISA a ch 85H iu khin chc nng I/O trn. Mun xc lp cc chn no ca PORTA l nhp (input) th ta set bit tng ng chn trong thanh ghi TRISA. Ngc li, mun chn no l output th ta clear bit tng ng chn trong thanh ghi TRISA. iu ny hon ton tng t i vi cc PORT cn li Ngoi ra, PORTA cn c cc chc nng quan trng sau : Ng vo Analog ca b ADC : thc hin chc nng chuyn t Analog sang Digital

Ng vo in th so snh Ng vo xung Clock ca Timer0 trong kin trc phn cng : thc hin cc nhim v m xung thng qua Timer0

Ng vo ca b giao tip MSSP (Master Synchronous Serial Port)

PORTB

PORTB c 8 chn. Cng nh PORTA, cc chn PORTB cng thc hin c 2 chc nng : input v output. Hai chc nng trn c iu khin bi thanh ghi TRISB. Khi mun chn no ca PORTB l input th ta set bit tng ng trong thanh ghi TRISB, ngc li mun chn no l output th ta clear bit tng ng trong TRISB. Thanh ghi TRISB cn c tch hp b in tr ko ln c th iu khin c bng chng trnh.

PORTC

PORTC c 8 chn v cng thc hin c 2 chc nng input v output di s iu khin ca thanh ghi TRISC tng t nh hai thanh ghi trn. Ngoi ra PORTC cn c cc chc nng quan trng sau :

Ng vo xung clock cho Timer1 trong kin trc phn cng

B PWM thc hin chc nng iu xung lp trnh c tn s, duty cycle: s dng trong iu khin tc v v tr ca ng c v.v.

Tch hp cc b giao tip ni tip I2C, SPI, SSP, USARTPORTD

PORTD c 8 chn. Thanh ghi TRISD iu khin 2 chc nng input v output ca PORTD tng t nh trn. PORTD cng l cng xut d liu ca chun giao tip song song PSP (Parallel Slave Port).

PORTE

PORTE c 3 chn. Thanh ghi iu khin xut nhp tng ng l TRISE. Cc chn ca PORTE c ng vo analog. Bn cnh PORTE cn l cc chn iu khin ca chun giao tip PSP.

d, Tm hiu v vi iu khin PIC16F877A

Cu trc phn cng ca PIC16F877A PIC l tn vit tt ca Programmable Intelligent computer do hng General Instrument t tn cho con vi iu khin u tin ca h. Hng Micrchip tip tc pht trin sn phm ny v cho n hng to ra gn 100 loi sn phm khc nhau. PIC16F887A l dng PIC kh ph bin, kh y tnh nng phc v cho hu ht tt c cc ng dng thc t. y l dng PIC kh d cho ngi mi lm quen vi PIC c th hc tp v to nn tn v h vi iu khin PIC ca mnh. Cu trc tng qut ca PIC16F877A nh sau : 8K Flash Rom 368 bytes Ram 256 bytes EFPROM 5 port vo ra vi tn hiu iu khin c lp 2 b nh thi Timer0 v Timer2 8 bit 1 b nh thi Timer1 16 bit c th hot ng c ch tit kim nng lng vi ngun xung clock ngoi 2 b Capture/ Compare/ PWM 1 b bin i Analog -> Digital 10 bit, 8 ng vo 2 b so snh tng t 1 b nh thi gim st (Watch Dog Timer) 1 cng song song 8 bit vi cc tn hiu iu khin 1 cng ni tip 15 ngun ngt

Hnh 2.14:S khi vi iu khin 16F877A

T chc b nh PIC16F877a + B nh chng trnh

Hnh 2.15: b nh chng trnh B nh chng trnh PIC16F877A B nh chng trnh ca vi iu khin PIC16F877A l b nh Flash, dung lng 8K word (1 word cha 14bit) v c phn thnh nhiu trang nh hnh trn. m ha c a ch 8K word b nh chng trnh, thanh ghi m chng trnh PC c dung lng 13 bit. Khi vi iu khin reset, b m chng trnh s tr v a ch 0000h. Khi c ngt xy ra th thanh ghi PC s tr n a ch 0004h. B nh chng trnh khng bao gm b nh Stack v khng c a ch ha bi b m chng trnh. B nh d liu B nh d liu ca PIC16F877A c chia thnh 4 bank. Mi bank c dng lng 128 byte. Nu nh 2 bank b nh d liu ca 8051 phn chia ring bit : 128 byte u tin thuc bank1 l vng Ram ni ch cha d liu, 128 byte cn li thuc bank 2 l cng cc thanh ghi c chc nng c bit SFR m ngi dng khng c cha d liu khc trong y th 4 bank b nh d liu ca PIC16F877A c t chc theo cch khc. Mi bank ca b nh d liu PIC16F877A bao gm c cc thanh ghi c chc nng c bit SFR nm cc cc nh a ch thp v cc thanh ghi mc ch dng chung GPR nm vng a ch cn li ca mi bank thanh ghi. Vng nh cc thanh ghi mc ch dng chung ny chnh l ni ngi dng s lu d liu trong qu trnh vit chng trnh. Tt c cc bin d liu nn c khai bo cha trong vng a ch ny. Trong cu trc b nh d liu ca PIC16F877A, cc thanh ghi SFR no m thng xuyn c s dng (nh thanh ghi STATUS) s c t tt c cc bank thun tin trong vic truy xut. S d nh vy l v, truy xut mt thanh ghi no trong b nh ca 16F877A ta cn phi khai bo ng bank cha thanh ghi , vic t cc thanh ghi s dng thng xuyn gip ta thun tin hn rt nhiu trong qu trnh truy xut, lm gim lnh chng

Hnh 2.16: S b nh d liu ca PIC16F877A

Da trn s 4 bank b nh d liu PIC16F877A ta rt ra cc nhn xt nh sau : Bank0 gm cc nh c a ch t 00h n 77h, trong cc thanh ghi dng chung cha d liu ca ngi dng a ch t 20h n 7Fh. Cc thanh ghi PORTA, PORTB, PORTC, PORTD, PORTE u cha bank0, do truy xut d liu cc thanh ghi ny ta phi chuyn n bank0. Ngoi ra mt vi cc thanh ghi thng dng khc ( s gii thiu sau) cng cha bank0.

Bank1 gm cc nh c a ch t 80h n FFh. Cc thanh ghi dng chung c a ch t A0h n Efh. Cc thanh ghi TRISA, TRISB, TRISC, TRISD, TRISE cng c cha bank1.

Tng t ta c th suy ra cc nhn xt cho bank2 v bank3 da trn s trn.

Cng quan st trn s , ta nhn thy thanh ghi STATUS, FSR c mt trn c 4 bank. Mt iu quan trng cn nhc li trong vic truy xut d liu ca PIC16F877A l : phi khai bo ng bank cha thanh ghi . Nu thanh ghi no m 4 bank u cha th khng cn phi chuyn bank.

* Mt vi thanh ghi chc nng c bit SFR

Thanh ghi STATUS: thanh ghi ny c mt c 4 bank thanh ghi cc a ch 03h, 83h, 103h v 183h : cha kt qu thc hin php ton ca khi ALU, trng thi reset v cc bit chn bank cn truy xut trong b nh d liu.

Thanh ghi OPTION_REG : c mt bank2 v bank3 c a ch 81h v 181h. Thanh ghi ny cho php c v ghi, cho php iu khin chc nng pull_up ca cc chn trong PORTB, xc lp cc tham s v xung tc ng, cnh tc ng ca ngt ngoi vi v b m Timer0

Thanh ghi INTCON : c mt c 4 bank a ch 0Bh,8Bh,10Bh,18Bh. Thanh ghi cho php c v ghi, cha cc bit iu khin v cc bit bo trn timer0, ngt ngoi vi RB0/INT v ngt khi thay i trng thi ti cc chn ca PORTB.

Thanh ghi PIE1 :a ch 8Ch, cha cc bit iu khin chi tit cc ngt ca cc khi chc nng ngoi vi.

Thanh ghi PIR1 : a ch 0Ch, cha c ngt ca cc khi chc nng ngoi vi, cc ngt ny c cho php bi cc bit iu khin cha trong thanh ghi PIE1.

Thanh ghi PIE2 : a ch 8Dh, cha cc bit iu khin cc ngt ca cc khi chc nng CCP, SSP b, ngt ca b so snh v ngt ghi vo b nh EEPROM.

Thanh ghi PIR2: a ch 0Dh, cha c ngt ca cc khi chc nng ngoi vi, cc ngt ny c cho php bi cc bit iu khin cha trong thanh ghi PIE2

Thanh ghi PCON : a ch 8Eh, cha cc c hiu cho bit trng thi cc ch reset ca vi iu khin.

Thanh ghi W(work) v tp lnh ca PIC16F877A

+Thanh ghi W y l thanh ghi rt c bit trong PIC16F877A. N c vai tr tng t nh thanh ghi Accummulator ca 8051, tuy nhin tm nh hng ca n rng hn rt nhiu. Tp lnh ca PIC16F877A c tt c 35 lnh th s lnh c s gp mt ca thanh ghi W l 23 lnh. Hu ht cc lnh ca PIC16F877A u lin quan n thanh ghi W. V d nh, trong PIC chng ta khng c php chuyn trc tip gi tr ca mt thanh ghi ny qua thanh ghi khc m phi chuyn thng qua thanh ghi W. Thanh ghi W c 8 bit v khng xut hin trong bt k bank thanh ghi no ca b nh d liu ca 16F877A. Mi dng lnh trong PIC16F877a c m t trong 14 bit. Khi ta thc hin mt lnh no , n phi lu a ch ca thanh ghi b tc ng (chim 8 bit) v gi tr mt hng s k no (thm 8 bit na) l 16 bit, vt qu gii hn 14 bit. Do vy ta khng th no tin hnh mt php tnh ton trc tip no gia 2 thanhghi vi nhau hoc gia mt thanh ghi vi mt hng s k. Hu ht cc lnh ca PIC16F877A u phi lin quan n thanh ghi W cng v l do . Khi thc hin mtdng lnh no , th PIC s khng phi tn 8 bit lu a ch ca thanh ghi W trong m lnh ( v c hiu ngm). C th xem thanh ghi W l thanh ghi trung gian trong qu trnh vit chng trnh cho PIC16F877A.e, Cc vn v Timer

PIC16F877A c tt c 3 timer : timer0 (8 bit), timer1 (16 bit) v timer2 (8 bit)Timer0

Hnh 2.17: S khi ca Timer0

Cng ging nh 8051, Timer0 ca 16F877A cng c 2 chc nng : nh thi v m xung. 2 chc nng trn c th c la chn thng qua bit s 5 TOCS ca thanh ghi OPTION. Ngoi ra, ta cng c th la chn cnh tch cc ca xung clock, cnh tc ng ngtthng qua thanh ghi trn. Timer0 c tch hp thm b tin nh 8 bit (prescaler), c tc dng m rng dung lng ca Timer0. B prescaler ny c th c iu chnh bi cc 3 bit PS2:PS0 trong thanh ghi OPTION. N c th c gi tr 1:2, 1:4, 1:8, 1:16, 1:32, 1:64, 1:128, 1:256 ty thuc vo vic thit lp cc gi tr 0 ,1 cho 3 bit trn. B tin nh c gi tr 1:2 chng hn ,c ngha l : bnh thng khng s dng b tin nh ca Timer0 (ng ngha vi tin nh t l 1:1) th c khi c tc ng ca 1 xung clock th timer0 s tng thm mt n v. Nu s dng b tin nh 1:4 th phi mt 4 xung clock th timer0 mi tng thm mt n v. V hnh chung, gi tr ca timer0 (8 bit) lc ny khng cn l 255 na m l 255*4=1020. Cc thanh ghi lin quan n Timer0 bao gm : TMR0 : cha gi tr m ca Timer0 INTCON : cho php ngt hot ng OPTION_REG : iu khin prescalerTimer1


Timer1 l b nh thi 16 bit, gi tr ca Timer1 s c lu trong hai thanh ghi 8 bit TMR1H:TMR1L. C ngt ca Timer1 l bit TMR1IF, bit iu khin ca Timer1 l TRM1IE. Cp thanh ghi ca TMR1 s tng t 0000h ln n FFFFh ri sau trn v 0000h. Nu ngt c cho php, n s xy ra khi khi gi tr ca TMR1 trn t FFFFh ri v 0000h, lc ny TMR1IF s bt ln. Timer1 c 3 ch hot ng :

Ch hot ng nh thi ng b : Ch c la chn bi bit TMR1CS. Trong ch ny xung cp cho Timer1 l Fosc/4, bit T1SYNC khng c tc dng. Ch m ng b : trong ch ny, gi tr ca timer1 s tng khi c xung cnh lnh vo chn T1OSI/RC1. Xung clock ngoi s c ng b vi xung clock ni, hot ng ng b c thc hin ngay sau b tin nh t l xung (prescaler). Ch m bt ng b :ch ny xy ra khi bit T1SYNC c set. B nh thi s tip tc m trong sut qu trnh ng ca vi iu khin v c kh nng to mt ngt khi b nh thi trng v lm cho Vi iu khin thot khi trng thi ng.

Timer2 : l b nh thi 8 bit bao gm mt b tin nh (prescaler), mt b hu nh Postscaler v mt thanh ghi chu k vit tt l PR2. Vic kt hp timer2 vi 2 b nh t l cho php n hot ng nh mt b inh thi 16 bit. Module timer2 cung cp thi gian hot ng cho ch iu bin xung PWM nu module CCP c chn.


2.8.2. Khi Hin Th.

Mn hnh LCD LM016L:

Hnh 2.20: mn hnh hin th LCDLM016L Ging nh led 7 thanh, LCD l mt thit b ngoi vi dng giao tip vi ngi dng, so vi led 7 thanh th LCD c u im l hin th c tt c cc k t trong bng m ascci, trong khi led 7 thanh ch hin th c mt s k t, nhng LCD li c nhc im l gi thnh cao v khong cch nhn gn. * Chc nng ca cc chn LCD : Chn K Hiu Mc Logic I/O Chc Nng

1 Vss - -Ngun (GND)

2 Vcc - -Ngun (+5V)

3 Vee - -Chnh tng phn

4 RS 0/1 I0=Nhp lnh

1=Nhp d liu

5 R/W 0/1 I0=Ghi d liu

1=c d liu

6 E 1,1 0 ITn hiu cho php

7 DB0 0/1 I/OBt d liu 0








15 Lamp- - -n LCD

16 Lamp+ - -n LCD

+ Cc chn Vcc, Vss v Vee

Chn Vcc cp dng ngun 5V, chn Vss ni t, chn Vee c dng iu khin tng phn ca mn hnh LCD. RS ( Register select): Khi mc thp, ch th c truyn n LCD nh xo mn hnh, v tr con tr .Khi mc cao, k t c truyn n LCD.

R/W (Read/Write): Dng xc nh hng ca d liu c truyn gia LCD v vi iu khin. Khi n mc thp d liu c ghi n LCD v khi mc cao, d liu c c t LCD. Nu chng ta ch cn ghi d liu ln LCD th chng ta c th ni chn ny xung GND tit kim chn + E (Enable). Cho php ta truy cp/xut n LCD thng qua chn RS v R/W.Khi chn E mc cao (1) LCD s kim tra trng thi ca 2 chn RS v R/W v p ng cho ph hp. Khi d liu c cp n chn d liu th mt xung mc cao xung thp phi c p n chn ny LCD cht d liu trn cc chn d liu. Xung ny phi rng ti thiu l 450ns. Cn khi chn E mc thp (0), LCD s b v hiu ho hoc b qua tn hiu ca 2 chn RS v R/W.

+ Cc chn D0 - D7

y l 8 chn d liu 8 bt, c dng gi thng tin ln LCD hoc c ni dung ca cc thanh ghi trong LCD. Cc k t c truyn theo m tng ng trong bng m ascii. Cng c cc m lnh m c th c gi n LCD xo mn hnh hoc a con tr v u dng hoc nhp nhy con tr. LCD c 2 ch giao tip, ch 4 bit (ch dng 4 chn D4 n D7 truyn d liu) v ch 8 bit (dng c 8 chn d liu t D0 n D7), ch 4 bit, khi truyn 1 byte, chng ta s truyn na cao ca byte trc, sau mi truyn na thp ca byte. Trc khi truyn cc k t ra mn hnh LCD ta cn thit lp cho LCD nh chn ch 4 bit hoc 8 bit, 1 dng hay 2 dng, bt/tt con tr Di y l bng tp lnh ca LCD :

* Bng Tp Lnh Ca LCD

M (Hex) Lnh n thanh ghi ca LCD

1 Xa mn hnh hin th

2Tr v u dng

4Gi con tr (dch con tr sang tri)

5Tng con tr (dch con tr sang phi)

6Dch hin th sang tri

7Dch hin th sang phi

8Tt con tr, tt hin th

ATt hin th, bt con tr

CBt hin th, tt con tr

EBt hin th, nhp nhy con tr

FTt con tr, nhp nhy con tr

10Dch v tr con tr sang tri

14Dch v tr con tr sang phi

18Dch ton b v tr hin th sang tri

1CDch ton b v tr hin th sang phi

80p con tr v u dng th nht

C0p con tr v u dng th hai

38Hai dng va ma trn 5x7

c thanh ghi lnh,ta phi t RS=0 v R/W =1 v xung cao xung thp cho bt E.Sau khi c thanh ghi lnh,nu bit D7(c bn ) mc cao th LCD bn, khng c thng tin hay lnh no c xut n n.Khi D7=0 mi c th gi lnh hay d liu n LCD.Nn kim tra bit c bn trc khi ghi thng tin ln LCD.

Ngoi LCD hin th th chng em cn dng cc loi LED pht quang hin th khi p sut thay i..2.8.3. Khi cm bin.

y l cm bin chng em s dng trong ti

Hnh 2.21: cm bin MPX4115 o p sut dng cm bin MPX4115. Tn hiu t cm bin to ra cc xung vung c tn s thay i ph thuc s bin i p sut ca mi trng bn ngoi. Do cc xung vung ny c a vo b vi x l m s xung trong khong thi gian cho php t c th tnh c gi tr p sut ca mi trng bn ngoi. y chnh l phng php m ngi ta s dng o p sut trong cc h thng ca cc nh my a ra cnh bo

Cc thng s ca cm bin MPX4115 nh sau:

+in p nh mc : 5V0.25(DC)

+Dng nh mc : 7mA(DC)

+Thi gian p ng :1ms

+0kpa 0.145psi

*nguyn l hot ng ca cm bin p sut.

C nhiu loi cm bin p sut khc nhau.mi loi cm bin c nguyn l hot ng khc nhau. y chng em xin trnh by v cm bin m chng em s dng: MPX4115

m hnh 1:

T m hnh ny ta thy khi in p bin i t 0.2675 n 4.7669V tng ng vi p sut bin i t 15 n 115Kpa. Quan h gia s bin i ca in p v p sut l quan h tuyn tnh. T ta c th xy dng c cng thc tm ra p sut.

S cc chn:

T m hnh ny ta c th bit c cch u ni cc chn ca cm bin trong mch khi s dng (style1).

Chn 1 u vi ngun ngoi

Chn 2 ni t

Chn 3 ni vi ngun 5VTa c th u theo 3 cch u nh trn: style1, style2, style3. S u cc chn:

Di p sut o.

Di p sut m cm bin c th o dc l t 15 n 115Kpa.

2.8.4. Bn phm.

Bn phm c s dng trong rt nhiu cc thit b, gip ngi s dng la chn cc chc nng ca thit b. C th ni giao tip bn phm l mt ng dng kh quan trng. Phm bm thng dng nht c cu to gm 2 u tip xc, mi khi chng ta bm phm, 2 u ny s chm vo nhau (xem hnh v s bn di).

Hnh 2.22: nt bm

Ngoi ra cn nhiu loi phm bm khc, v cu to cng khc, c th l phm bm thng ng, khi ta bm phm th 2 u tip xc khng thng nhau. Hoc cng c loi phm bm cm ng, da trn s thay i in tr ca mng in tr, hoc da trn s thay i in dung hay in cm mi khi c tay ngi chm vo. 2.8.5. Khi ngun. My bin p 220v/15v

Nguyn l hoy ng

( Gi Np, Up, Ip v Ns,Us,Is ln lt l s vng dy, hiu in th, dng in trong mch in s cp v th cp - Dng in chy qua dy dn cun s cp to ra t thng

Dng in c to ra trong cun dy s cp khi ni vi hiu in th s cp, v 1 t thng bin thin trong li st. T thng bin thin ny mc vng qua qun dy th cp v cm ng trn cun dy th cp mt hiu din th,nu ni kn mch to ra mt dng in: v NuS=Pth,

ngoi ra (my bin th l tng).

*v d

in p li in 220v,0.5A

in p sau bin p 24v ,4.58A

2.8.6. Cc loi linh kin khc. + Thch anh dao ng :

( Thch anh c th c s dng ch to cc thit b to ra xung nhp ng dng trong ngnh in t, cng c th dng to cc tn s mu hiu chnh. Trong mch chng em s dng thch anh X1-12MHZ( X1 : l thch anh to dao ng , tn s dao ng c ghi trn thn ca thach anh, khi thch anh c cp in th n t dao ng ra sng hnh sin.thch anh thng c tn s dao ng t vi trm KHz n vi chc MHz. + Tranzitor

( Transistor l mt linh kin bn dn thng c s dng nh mt thit b khuch i hoc mt kha in t. Tranzitor l khi n v c bn xy dng nn cu trc mch my tnh in t v tt c cc thit b in t hin i khc. V p ng nhanh v chnh xc nn cc tranzitor c s dng trong nhiu ng dng tng t v s, nh khuch i, ng ct, iu chnh in p, iu khin tn hiu, v to dao ng.Tranzitor cng thng c kt hp thnh mch tch hp (IC),c th tch hp ti mt t tranzitor trn mt din tch nh.

Hnh 2.23: Mt s tranzito

( Cng ging nh it, tranzito c to thnh t hai cht bn dn in. Khi ghp mt bn dn in m nm gia hai bn dn in dng ta c mt PNP tranzito. Khi ghp mt bn dn in dng nm gia hai bn dn in m ta c mt NPN tranzito.

( Cc loi Tranzito chng em dng trong mch: 2N2907, 2N2926, 2N3019, 2N3415

+Cc loi in tr...CHNG 3: XY DNG H THNG3.1. Xy Dng Phn Cng

H thng s gm nm khi nh phn tch chng hai, ta s c s nguyn l v mch m phng nh sau. ( mch m phng mt s hnh nh chy th.

a, o p sut v hin th trn mn hnh.

Hnh 3.1: hnh nh m phng chy th

b, o p sut, iu chnh ngng, hin th mn hnh v a ra cnh bo.

+iu chnh ngng thp

Hnh 3.2 +Cnh bo ngng thp

Hnh 3.3 +iu chnh ngng cao.

Hnh 3.4 +a ra cnh bo ngng cao.

Hnh 3.53.2. Xy Dng Phn Mm

Vic thit k phn mm cho h thng chnh l vic xy dng chng trnh iu khin np vo Vi iu khin. Trc tin phi c s thut ton iu khin x l cc vn v nguyn tc hot ng ca mch.

Cc vn t ra l:

Hin th v a ra cnh bo p sut.

Ci t ngng cnh bo p sut Chng trnh:

// YEU CAU BAI TOAN

//DO VA HIEN THI AP SUAT TRONG KHONG GII HN NO . NU AP SUAT O NM NGOAI GIOI HAN THI DUA RA CANH BAO

//CAM BIEN DUNG LA LA MPX4115 VOI GIOI HAN DO TU 15 TOI 115KP

// DIEN AP RA VOI 15 KP THI Vs=0.2675

//DIEN AP RA VOI 115KP THI Vs=4.76693

//DUNG ADC 10 BIT

#include

#device *=16 adc=10

#FUSES NOWDT, HS, NOPUT, NOPROTECT, NODEBUG, NOBROWNOUT,NOLVP, NOCPD, NOWRT

#use delay(clock=20000000)

#include

#define ht input(pin_a4)

#define nut1 input(pin_b0)




int8 tram,chuc,donvi;

int16 kq ;

int8 max=100,min=20;

void convert_bcd(int16 x,float z)

{

float k;int8 b;

tram=x/100; //hang tram

chuc=(x/10)%10; //tach hang tram va hang chuc

donvi=(x%10); // hang doi vi

}

void main()

{

set_tris_a(0xFF);

set_tris_b(0xFF);

setup_adc_ports(AN0_VREF_VREF);

setup_adc(ADC_CLOCK_INTERNAL);

set_tris_c(0x00);

output_c(0x00);

LCD_init();

LCD_putcmd(0x01);

printf(LCD_putchar,"apsuatla:");

while(1)

{

if (nut1)

{

output_low(pin_c2);

if(nut2) max=max+1;

delay_ms(10);

if(nut3)max=max-1;

delay_ms(10);

tram=max/100; //hang tram

chuc=(max/10)%10; //tach hang tram va hang chuc

donvi=(max%10); // hang doi vi

LCD_putcmd(0x01);

printf(LCD_putchar,"as nguong cao");

LCD_putcmd(0xC0);

LCD_putchar(tram+0x30);

LCD_putchar(chuc+0x30);

LCD_putchar(donvi+0x30);

delay_ms(500);

LCD_putcmd(0x01);

printf(LCD_putchar,"ap suat la");

}

else

if (nut4)

{

output_low(pin_c2);

if(nut2) min=min+1;

delay_ms(10);

if(nut3)min=min-1;

delay_ms(10);

tram=min/100; //hang tram

chuc=(min/10)%10; //tach hang tram va hang chuc

donvi=(min%10); // hang doi vi

LCD_putcmd(0x01);

printf(LCD_putchar,"as nguong thap");

LCD_putcmd(0xC0);




delay_ms(500);

LCD_putcmd(0x01);

printf(LCD_putchar,"ap suat la");

}

else

{

kq=(float)read_adc();

kq=(float)kq*100/1023+15;

if(kqmax)

S{

LCD_putcmd(0x01);

printf(LCD_putchar,"ap suat rat cao");

convert_bcd(kq,kq);

LCD_putcmd(0xC0);




printf(LCD_putchar,"kpa");

output_high(pin_c0);

output_low(pin_c2);

delay_ms(2500);

}

else

{

output_high(pin_c2);

convert_bcd(kq,kq);

LCD_putcmd(0xC0);




printf(LCD_putchar,"kpa");

}

}

}

}

Max=max

Min=min

Hin th LCD

S

S

S

Hnh 1.1. thit b kim sot p sut bnh xe

S

Cnh bo

Min=min-1

Min=min+1

Max=max+1

Max=max-1

S

Nt3=1

Nt1=1

Chng trnh chnh

Nt4=1

Nt2=1

Nt3=1

Nt2=1

Kqmax

Khi to ngng max,min

Khi ng

LCD

Cm bin

Bn phm

ADC

Chng trnh hin th LCD

Chng trnh o p sut

Chng trnh kt ni bn phm

Chng trnh chuyn i ADC

Vi x l, vi iu khin

Pmax

Tn hiu

minpmax

Tn hiu

Pmax

Hin th

Ngng kch hot

Kim tra

Kch hot

Kim tra ban u

i tn hiu

Khi

tng tc iu khin

Khi cm bin

Thit b

chp hnh

Khi hin th

Khi

x

l

trung

tm

Khi ngun

a,Phn t o trong lng lp gn trn vnh bnh

b,Phn nhn tn hiu trong xe

S

S

n Mn Hc ((( B Mn K Thut My Tnh Trang 55

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