N MN HC 2

NHN XT CA GING VIN HNG DN...................................................................................................................................................... ...................................................................................................................................................... ...................................................................................................................................................... ...................................................................................................................................................... ...................................................................................................................................................... ...................................................................................................................................................... ...................................................................................................................................................... ...................................................................................................................................................... ...................................................................................................................................................... ...................................................................................................................................................... ...................................................................................................................................................... ...................................................................................................................................................... ...................................................................................................................................................... ...................................................................................................................................................... ...................................................................................................................................................... ...................................................................................................................................................... ...................................................................................................................................................... ...................................................................................................................................................... ...................................................................................................................................................... ...................................................................................................................................................... ...................................................................................................................................................... ...................................................................................................................................................... ...................................................................................................................................................... ...................................................................................................................................................... ...................................................................................................................................................... ...................................................................................................................................................... ...................................................................................................................................................... ...................................................................................................................................................... ......................................................................................................................................................

Ngy

Thng

Nm 2012

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MC LCNHN XT CA GING VIN HNG DN .................................................................. 1 I/ T VN ......................................................................................................................... 4 II/ GII THIU H THNG L P TRNG TRN THTRNG ...................................... 4 a.My p trng GTL -1000.......................................................................................................... 4 b.My p trng OXY GTL 240K ................................................................................................ 4 I/ PHN TCH BI TON V CC GII PHP .................................................................... 7 1. Chc nng ca ti: .............................................................................................................. 7 2. gii php la chn ti: ......................................................................................................... 7 4.L thuyt iu khin PID........................................................................................................ 15 5. Tm tt PID ........................................................................................................................... 19 CHNG III: THIT K PHN CNG H THNG ........................................................... 46 I/ CC MODULE TRONG H THNG ................................................................................. 46 1. Module iu khin ................................................................................................................. 46 2.Module ci t ........................................................................................................................ 46 3. Module hin th ...................................................................................................................... 46 4. Module cp nhit ................................................................................................................... 46 5. Module khi ngun................................................................................................................ 46 6. Module cm bin ................................................................................................................... 46

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LI NI UTh k 21 m ra mt thi i mi , thi i khoa hc cng ngh i hi con ngi lun lun khng ngng tm ti hc tp tin b .Vi s nhy vt ca khoa hc, k thut in t l nghnh mi pht trin ch trong thi gian ngn n t c nhng thnh tu to ln hu ht cc lnh vc khc nhau trong i sng x hi.Thit b v cng ngh lun c i mi tin tin hin i gp phn nng cao cht lng cng nh cc my mc ,thit b hot ng c hiu qu , an ton n nh . Ngy nay cc b vi iu khin ang c ng dng ngy cng rng ri trong cc lnh vc k thut v i sng x hi, c bit l trong k thut t ng ha v iu khin t xa. Gi y vi nhu cu chuyn dng ha, ti u (thi gian ,khng gian ,gi thnh) bo mt, tnh ch ng trong cng vicngy cng i hi kht khe.vic a ra cng ngh mi trong lnh vc ch to mch in t p ng nhng nhu cu trn l hon ton cp thit mang tnh thc t cao. K thut vi iu khin hin nay rt pht trin, n c ng dng vo rt nhiu lnh vc sn xut cng nghip, t ng ha, trong i sng v cn nhiu lnh vc khc na. So vi k thut s th k thut vi iu khin nh gn hn rt nhiu do n c tch hp li v c kh nng lp trnh c iu khin nn rt tin dng v c ng. Vi tnh u vit ca vi iu khin th trong phm vi n nh ny, chng em ch dng vdk iu khin v o nhit , ng thi cho hin th ln LCD. n mn hc c thc hin bng cc kin thc hc ,mt s sch tham kho v mt s ngun ti liu khc .Tuy nhin do thi gian v trnh c hn nn chng em khng th trnh khi nhng thiu st. V vy rt mong c s gip , ng gp kin ca thy v cc bn nhm c th hon thnh n ca mnh mt cch tt nht. Chng em xin trn thnh cm n

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CHNG I: PHN TCH H THNGI/ T VN Ngy nay do s pht trin ca khoa hc k thut ang tc ng n cc lnhvc, c bit l lnh vc in t to ra bc nhy vt vt bc trong nhiu lnh vc ca i sng x hi . Ngay c trong trng trt ,chn nui cng c p dng khoa hc cng ngh t nng sut cao nht.L sinh vin ca nghnh t ng ha nhm mong mun to ra mt h thng t ng p dng trong chn nui. Chng em t bi ton vi mt l p trng gia cm. Ngi ta thng cho trng p nhit c nh cho php. Tuy nhin nhit trong l lun thay i v ph thuc vo nhit mi trng. V vy chng em mong mun c nghin cu thit k ra h thng n nh nhit l p trng nhm t ng o v hin th nhit ca mi trng mt thi im bt k trong khong t 0 n 255 C .V n nh khi nhit ca mi trng khng nm trong mt khong nhit no m ta chn. II/ GII THIU H THNG L P TRNG TRN THTRNG 1. Nguyn l hot ng ca cc my p trng trn th trng Cc my p trng hot ng t ng 100% c iu khin bi mt module iu khin chnh. Module ny nhn thng tin t module cm bin nhit , sau pht tn hiu iu khin module cp nhit . ngoi ra my p trng cn c thm module t nhit p trng, thi gian ptrng- Mt s my p trng sau : a.My p trng GTL -1000 My p trng GTL -1000 :t ng hon ton 100% , cng xut ti a1000 trng, o trng t ng (ch hn gi), phun m v nhit tu chnh t ng ng khi qua con s quy nh in p : 220V AC Cng sut tiu th:10kw / 1 k p Kt cu : Phun m :Tu chnh , t ng ng ngt khi qu % quy nh H thng cung cp nhit :Bng nhit halozen chuyn dng cho p trng o Trng :T chn hn gi t 30 Pht - 120 Gi . Nhit c iu khin t ng,n nh bng vi x l. To m t ng o trng t ng (c th tu chn thi gian o t 1 gi - 120 gi ) C th p theo ch a k(mi tun vo trng mt ln) hoc n k b.My p trng OXY GTL 240K L loi my p trng o trng bng kh- in p : 220V AC- Cng sut tiu th: 2kw in / 1 k p- H thng cp nhit :in tr - Nhit c iu khin t ng bng vi x l- T ng trn kh oxy- C th p theo ch a k , hoc n k.

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Hnh 1: My p trng oxy GTL240K v mt s loi my p trng khc.

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PHN 2:NI DUNGI/ PHN TCH BI TON V CC GII PHP 1. Chc nng ca ti: o v hin th nhit ca mi trng mt thi im bt k trong khong t 0 n 255. n nh khi nhit ca mi trng khng nm trong mt khong nhit no m ta chn(sai s + - 2 c). o nhit ca l p trng. o nhit t 0 n 255 C. C th ci t nhit theo yu cu Lm vic vi in p 220v/50 HZ. Dng sensor cm ng nhit. Senser gi v tn hiu in p. Khi nhit tng cao qu mt gii hn no th tt cp nhit Khi nhit gim thp qu mt gii hn no th bt cp nhit H thng lm vic c khi mt in li (c ngun d tr). 2. gii php la chn ti: Cc tiu chun la chn b vi iu khinTiu chun u tin v trc ht trong la chn mt b vi iu khin l n phi p ng nhu cu bi ton v mt cng sut tinh ton,gi thnh v hiu qu.Trong khi phn tch cc nhu cu ca mt d n trn b vi iu khin, chng ta phi bit trc ht l cc b vi iu khin no l 8 bit, 16 bit,32 bit c th p ng tt nht nhu cu tnh ton ca bi ton mt cch hiu qu nht. a)Nhng tiu chun c a ra cn nhc l: Tc : tc ln nht m b vi iu khin h tr l bao nhiu. Kiu ng v:y l iu quan trng i vi yu cu v khng gian,kiu lp gip v to mu th cho sn phm cui cng. Cng sut tiu th: iu ny c bit khc khe vi nhng sn phm dng pin,c quy. Dung lng b nh rom v ram trn chip Kh nng nng cp cho hiu sut cao hoc gim cng sut tiu th. Gi thnh cho mt n v:iu ny quan trng quyt nh gi thnh cui cng ca sn phm m mt b vi iu khin c s dng b. La chn thit b: Qua tm hiu, tham kho mt s ti liu trn internet, nhm chng em quyt nh la chn b vi iu khin AT89C51, cm bin nhit DS18B20 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 tnh ton C sn cc cng c pht trin phn mm chng hn nh trnh bin dch CCS.GVHD:ThS. V TH NG Page 7

N MN HC 2 Ngun cc b vi s l c sn nhiu v tin cy II/ PHNG PHP IU KHIN CNG SUT B PHT NHIT BNG PWM PWM l ci g m sao n c ng dng nhiu trong iu khin. Ly in hnh nht m chng ta thng hay gp l iu khin ng c v cc b bm xung p, iu p... S dng PWM iu khin nhanh chm ca ng c hay cao hn na n cn c dng iu khin n nh tc ng c. Ngoi lnh vc iu khin hay n nh ti th PWM n cn tham gia v iu ch cc mch ngun nh l: boot, buck, nghch lu 1 pha v 3 pha...PWM chng ta cn gp nhiu trong thc t v cc mch in iu khin. iu c bit l PWM chuyn dng iu khin cc phn t in t cng sut c ng c tnh l tuyn tnh khi c sn 1 ngun 1 chiu c nh .Nh vy PWM n c ng dng rt nhiu trong cc thit b in in t. iu m dn in in t d dng nhn ra l PWM chnh nhn t m cc i Robocon s dng iu khin ng c hay n nh tc ng c. 1.PWM Trc khi tm hiu su chng ta hy tm hiu nh ngha ca PWM l g? Nh vy Phng php iu ch PWM c tn ting anh l Pulse Width Modulation l phng php iu chnh in p ra ti hay ni cch khc l phng php iu ch da trn s thay i rng ca chui xung vung dm m s thay i in p ra. Cc PWM khi bin i th c cng 1 tn s v khc nhau v rng ca sn dng hay hoc l sn m

S nguyn l iu khin ti dng PWM

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Trn l th dng xung khi iu khin bng PWM. Vi rng xung u ra tng ng v c tnh bng %. Ty thch do chng ta iu khin. 2.Nguyn l ca PWM. y l phng php c thc hin theo nguyn tc ng ngt ngun vi ti l mt cch c chu k theo lut iu chnh thi gian ng ct. Phn t thc hin nhin v trong mch cc van bn dn. Xt hot ng ng ct ca mt van bn dn. Dng van ng ct bng Mosfet

Trn l th dng xung khi iu khin bng PWM. Vi rng xung u ra tng ng v c tnh bng %. Ty thch do chng ta iu khin. Gin xungGVHD:ThS. V TH NG Page 9

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Trn l mch nguyn l iu khin ti bng PWM v gin xung ca chn iu khin v dng in p u ra khi dng PWM. * Nguyn l : Trong khong thi gian 0 - to ta cho van G m ton b in p ngun Ud c a ra ti. Cn trong khong thi gian to - T cho van G kha, ct ngun cung cp cho ti. V vy vi to thay i t 0 cho n T ta s cung cp ton b, mt phn hay kha hon ton in p cung cp cho ti. + Cng thc tnh gi tr trung bnh ca in p ra ti : Gi t1 l thi gian xung sn dng (kha m ) cn T l thi gian ca c sn m v dng, Umax l in p ngun cung cp cho ti. ==> Ud = Umax.( t1/T) (V) hay Ud = Umax.D Vi D = t1/T l h s iu chnh v c tnh bng % tc l PWM Nh vy ta nhn trn hnh th dng iu ch xung th ta c : in p trng bnh trn ti s l: + Ud = 12.20% = 2.4V ( vi D = 20%) + Ud = 12.40% = 4.8V (Vi D = 40%) + Ud = 12.90% = 10.8V (Vi D = 90%) 3. Cc cch to ra c PWM iu khin to c ra PWM th hin nay c hai cch thng dng : Bng phn cng v bng phn mm. Trong phn cng c th to bng phng php so snh hay l t trc tip t cc IC dao ng to xung vung nh : 555, LM556...Trong phn mn c to bng cc chip c th lp trnh c. To bng phn mm th chnh xc cao hn l to bng phn cng. Nn ngi ta hay s dng phn mm to PWM a) To bng phng php so snhGVHD:ThS. V TH NG Page 10

N MN HC 2 to c bng phng php so snh th cn 2 iu kin sau y : Tn hiu rng ca : Xc nh tn s ca PWM Tn hiu ta l tn hiu xc nh mc cng sut iu ch (Tn hiu DC) Xt s mch sau :

Vi tn s xc nh c l f = 1/(ln.C1.(R1+2R2) nn ch cn iu chnh R2 l c th thay i rng xung d dng. Ngoi 555 ra cn rt nhiu cc IC to xung vung khc c. To xung vung bng phn mm. y l cch ti u trong cc cch to c xung vung. Vi to bng phn mm cho chnh xc cao v tn s v PWM. Vi li mch ca chng ta n gin i rt nhiu. Xung ny c to da trn xung nhn ca CPU. Ly 1 on v d to PWM trong con 8501 :

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Trn l chng trnh to PWM n gin.

III/ Gii thiu iu khin PID1.Gii thut iu khin PID PID l cch vit tc ca cc t Propotional (t l), Integral (tch phn) v Derivative (o hm). Tuy xut hin rt lu nhng n nay PID vn l gii thut iu khin c dng nhiu nht trong cc ng dng iu khin t ng. gip bn c ci hiu r hn bn cht ca gii thut PID ti s dng mt v d iu khin v tr ca mt car (xe) trn ng thng. Gi s bn c mt xe ( chi...) c gn mt ng c DC. ng c sinh ra mt lc y xe chy ti hoc lui trn mt ng thng nh trong hnh bn di.

V d iu khin v tr xe trn ng thngGVHD:ThS. V TH NG Page 12

N MN HC 2Gi F l lc do ng c to ra iu khin xe. Ban u xe v tr A, nhim v t ra l iu khin lc F (mt cch t ng) y xe n ng v tr O vi cc yu cu: chnh xc (accurate), nhanh (fast response), n nh (small overshot). Mt iu rt t nhin, nu v tr hin ti ca xe rt xa v tr mong mun (im O), hay ni cch khc sai s(error) ln, chng ta cn tc ng lc F ln nhanh chng a xe v O. Mt cch n gin cng thc ha tng ny l dng quan h tuyn tnh: F=Kp*e (1) Trong Kp l mt hng s dng no m chng ta gi l h s P (Propotional gain), e l sai s cn iu khin tc khong cch t im O n v tr hin ti ca xe. Mc tiu iu khin l a e tin v 0 cng nhanh cng tt. R rng nu Kp ln th F cng s ln v xe rt nhanh chng tin v v tr O. Tuy nhin, lc F qu ln s gia tc cho xe rt nhanh (nh lut II ca Newton: F=ma). Khi xe n v tr O (tc e=0), th tuy lc F=0 (v F=Kp*e=F=Kp*0) nhng do qun tnh xe vn tip tc tin v bn phi v lch im O v bn phi, sai s e li tr nn khc 0, gi tr sai s lc ny c gi l overshot (vt qu). Lc ny, sai s e l s m, lc F li xut hin nhng vi chiu ngc li ko xe v li im O. Nhng mt ln na, do Kp ln nn gi tr lc F cng ln v c th ko xe lch v bn tri im O. Qu trnh c tip din, xe c mi dao ng quanh im O. C trng hp xe dao ng cng ngy xng xa im O. B iu khin lc ny c ni l khng n nh. Mt xut nhm gim overshot ca xe l s dng mt thnh phn thng trong b iu khin. S rt l tng nu khi xe ang xa im O, b iu khin sinh ra lc F ln nhng khi xe tin gn n im O th thnh phn thng s gim tc xe li. Chng ta u bit khi mt vt dao ng quanh 1 im th vt c vn tc cao nht tm dao ng (im O). Ni mt cch khc, gn im O sai s e ca xe thay i nhanh nht (cn phn bit: e thay i nhanh nht khng phi e ln nht). Mt khc, tc thay i ca e c th tnh bng o hm ca bin ny theo thi gian. Nh vy, khi xe t A tin v gn O, o hm ca sai s e tng gi tr nhng ngc chiu ca lc F (v e ang gim nhanh dn). Nu s dng o hm lm thnh phn thng th c th gim c overshot ca xe. Thnh phn thng ny chnh l thnh phn D (Derivative) trong b iu khin PID m chng ta ang kho st. Thm thnh phn D ny vo b iu khin P hin ti, chng ta thu c b iu khin PD nhu sau: F=Kp*e+Kd*(de/dt) (2) Trong (de/dt) l vn tc thay i ca sai s e v Kd l mt hng s khng m gi l h s D (Derivative gain). S hin din ca thnh phn D lm gim overshot ca xe, khi xe tin gn v O, lc F gm 2 thnh phn Kp*e > =0 (P) v Kd*(de/dt) Tng quan v DS18B20 v bus 1 dy: DS18B20 l cm bin nhit sn phm ca cng ty Dallas (M), y cng l cng ty gp phn nhiu vo vic cho ra i bus 1 dy v cc cm bin 1 dy. - Hnh dng cc cm bin c m t nh hnh v,trong dng TO-92 vi 3 chn l dng thng gp v c dng nhiu trong cc ng dng.Cn dng v SOIC vi 8 chn c dng o nhit b mt k c da ngi.

Hnh 2 : Hnh dng cm bin DS18B20

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N MN HC 2Cc c im k thut ca DS18B20 c th c k ra 1 cc tm tt nh sau: - S dng giao din 1 dy nn ch cn 1 dy ra truyn tn hiu. phn gii o nhit c th chn t 9-12 bit. - Di o nhit t -55 125 C tng bc 0.5 C c th chnh xc ti 0.1 C bng vic hiu chnh bng phn mm. - Thch hp cho cc ng dng o lng a im v nhiu u o c th c ni trn cng 1 bus, bus ny gi l bus 1 dy ( 1-wire) m khng cn thm linh kin bn ngoi.

Hnh 3: kt ni bus 1 dy. - in p ngun nui c th thay i trong khong rng t 3.0 5.5 V v c th cp ngun thng qua ng dn tn hiu ( ch cp ngun k sinh) khng cn dy dn ngun nui. Dng tiu th ch ngh cc nh. Thi gian ly mu v chuyn i thnh s tng i nhanh khng qu 750ms. - u o nhit s DS18B20 a ra s liu biu th nhit di dng m nh phn nn khng cn b chuyn t tn hin tng t sang s (ADC). - Cc tn hiu c gi n v nhn v t DS18B20 trn giao din 1 dy nn ch cn 2 dy ,1 dy lm ng tn hiu v 1 dy lm t l kt ni vi iu khin n im o. - Mi cm bin c 1 m nh danh duy nht 64bit cha trong b nh Rom trn chip c khc bng lazer trong qu trnh ch to vi mch, nn nhiu vi mch DS18B20 cng gn trn 1 bus 1- wire m khng c s nhm ln.c im ny lm cho vic lp t nhiu cm bin nhit ti nhiu ni trn bus 1 dy vi chi ph thp. Theo chun 1- wire chiu di ti a ca bus l 300m v khng gii hn s lng cm bin gn vo bus. b> Cm bin DS18B20:

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N MN HC 2Hnh 4: cm bin DS1820 - chn GND:chn ni t. - chn DQ:chn trao i d liu, ng thi l chn cp ngun cho ton b hot ng ca Ic nu s dng ch ngun k sinh. Khi kt ni vi vi iu khin th cn phi c in tr ko ln khong 4.7k. - chn Vcc: chn cp ngun. Cu trc ca cm bin DS18B20:

Hnh 5: S khi cm bin DS18B20 T chc b nh: - Mi IC DS1820 c mt m 64bit ring bit bao gm: 8bit Familly code, 48bits CRC code c lu trong Rom.Cc gi tr ny gip phn bit gia cc IC vi nhau trn cng 1 bus.Gi tr Familly code ca DS1820 l 28h v gi tr CRC l kt qu ca qu trnh kim tra 56 bits trc . - T chc b nh Scratchpad: B nh DS1820 bao gm 9 thanh ghi 8bits: Byte 0 v 1 lu gi tr nhit chuyn i. Byte 2 v 3 lu gi tr ngng nhit . ( khng b mt khi mt in). Byte 4 l thanh ghi cu hnh cho hot ng ca DS1820. Byte 5,6 v 7 khng s dng. Byte 8 l thanh ghi ch c lu gi tr CRC t byte 0 n byte 7. Ba bc truy cp DS18B20: Trao i d liu gia vi iu khin v DS1820 thng qua ba bc sau: o Khi to: Qu trnh khi to bao gm 1 xung reset do vi iu khin master gi n slave DS1820, sau l xung presence t DS1820 gi n vi iu khin, ch ra s hin din ca vi iu khin v DS1820 v qu trnh hot ng trao i d liu c th bt u. o Lnh iu khin ROM:

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N MN HC 2Cc lnh ny lm vic vi 64bits serial code ROM, lnh ny c pht ra sau qu trnh khi to. Lnh cho php vi iu khin bit c bao nhiu thit b v thit b loi g trn bus. C 5 lnh iu khin ROM: - SEARCH ROM [F0h] Khi h thng bt u hot ng, th vi iu khin s dng lnh ny kim tra code ROM ca tt c cc thit b c trn bus cho php vi iu khin bit c s thit b v loi ca thit b trn bus. Nu trn bus ch c 1 thit b th c th s dng lnh Read_ROM thay cho lnh Search_ROM. Sau mi qu trnh Search_ROM th cn phi quay li qu trnh khi to reset h thng. - READ ROM [33h] Lnh ny c s dng khi ch c 1 thit b trn bus. Lnh ny cho php vi iu khin c 64bit ROM code ca thit b. Nu trn bus c nhiu thit b th lnh ny s gy ra s xung t bus d liu gia cc thit b. - MATCH ROM [55h] Lnh ny theo sau bi 64 bit ROM code cho php vi iu khin nh a ch thit b cn giao tip. Ch thit b c ROM code ph hp s tr li, cc thit b cn li s i xung reset tip theo. - SKIP ROM [CCh] Lnh ny cho php vi iu khin gi ng thi n tt c cc thit b trn bus m khng cn bt c thng tin no v ROM Code. V d, mun gi lnh Convert_T n tt c cc thit b trn bus, th u tin ta gi lnh Skip_ROM sau tip theo l gi lnh Convert_T. Tng t nh vy, nu theo sau lnh Skip_ROM l lnh Read_Scratchpad th d liu trn DS1820 c c v, v lu rng lnh ny ch thc hin c khi trn bus c 1 thit b, nu trn bus c nhiu thit b th s gy ra xung t bus. - ALARM SEARCH [ECh] Lnh ny gn ging vi lnh Search_ROM, nhng lnh ny ch tc ng n thit b m c alarm c bt ln s tr li. Lnh ny cho php xc nh cc thit b m nhit o c vt qua ngng nhit , v sau khi lnh ny c thc thi th vi iu khin phi lp li qu trnh khi to quay li bc 1. Lnh iu khin DS1820: Sau khi vi iu khin nh a ch thit b cn giao tip thng qua cc lnh ROM, vi iu khin s gi cc lnh iu khin hot ng ca DS1820. Nhng lnh ny cho php vi iu khin ghi v c d liu t b nh Scratchpad ca DS1820, bt u qu trnh chuyn i nhit , v xc nh ch cp ngun. - WRITE SCRATCHPAD (4Eh) Lnh ny cho php ghi 2 byte d liu vo b nh nhp ca DS1820. Byte u tin c ghi vo thanh ghi TH (byte 2 ca b nh nhp) cn byte th hai c ghi vo thanh ghi TL (byte 3 ca b nh nhp). D liu truyn theo trnh t u tin l bit c ngha thp nht ( LSB). C hai byte ny phi c ghi trc khi thit b ch xut ra mt xung reset hoc khi c d liu khc xut hin.GVHD:ThS. V TH NG Page 38

o

N MN HC 2- READ SCRATCHPAD (BEh) Lnh ny cho php thit b ch c ni dung b nh nhp. Qu trnh c bt u t bit c ngha thp nht (LSB) ca byte 0 v tip tc cho n byte rh 9 (byte 8 - CRC). Thit b ch c th xut ra mt xung reset lm dng qu trnh c bt k lc no nu nh ch c mt phn ca d liu trn b nh nhp cn c c. - COPYSCRATCHPAD (48h) Lnh ny copy ni dung ca hai thanh ghi TH v TL (byte 2 v byte 3) vo b nh EEPROM. Nu cm bin c s dng trong ch cp ngun l bt u vic o. - CONVERT T (44h) Lnh ny khi ng mt qu trnh o v chuyn i gi tr nhit thnh s (nh phn). Sau khi chuyn i gi tr kt qu o nhit c lu tr trn thanh ghi nhit 2 byte trong b nh nhp Thi gian chuyn i khng qu 200 ms, trong thi gian ang chuyn i nu thc hin lnh c th cc gi tr c ra u bng 0. - READ POWER SUPPLY (B4h) Mt lnh c tip sau lnh ny s cho bit DS1820 ang s dng ch cp ngun nh th no, gi tr c c bng 0 nu cp ngun bng chnh ng dn d liu v bng 1 nu cp ngun qua mt ng dn ring. Nguyn l hot ng ca cm bin nhit DS18B20: Bn trong DS18B20 c b chuyn gi tr nhit sang gi tr s v c lu trong cc thanh ghi b nh cratchpad. phn gii nhit o c th c cu hnh ch 9bits, 10bits,11bits,12bits. ch mc nh th DS18B20 hot ng phn gii 12bits. bt u qu trnh c nhit v chuyn i t gi tr tng t sang gi tr s th VDK gi lnh COVERT T [44h], sau khi chuyn i xong th gi gi tr nhit c lu trong 2 thanh ghi nhit b nh cratchpad v IC tr v trng thi ngh. Nhit c lu bn trong DS19B20 c tnh nhit Celcius. Gi tr nhit lu trong b nh gm 2bytes- 16 bits: s m c lu di dng b 2. bit cao nht l bit du (S) nu S=0 th gi tr nhit l dng v S=1 th gi tr nhit l m Nu cu hnh phn gii l 12bits th tt c cc bit u c s dng. Nu phn gii 11bits th bit 0 khng c s dng.Tng t nu cu hnh l 10bits th bit 1,0 khng c s dng, nu cu hnh 9bits th bit 2,1,0 khng c s dng.

Hnh 6: nh dng thanh ghi lu gi tr nhit .

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N MN HC 2

Hnh 7: Gi tr nhit v gi tr c lu trong b nh. Gi tr nhit sau khi c lu vo trong hai thanh ghi b nh s c so snh vi 2 thanh ghi ngng nhit TH v TL. Cc gi tr nhit do ngi dng quy nh v n s khng thay i khi mt in. Nh vy ch c phn nguyn cc, cc bit t 11-4 ca gi tr nhit c so snh vi 2 thanh ghi ngng.Nu gi tr nhit c v nh hn mc TL hoc ln hn mc TH th c bo qu nhit s c bt ln, v n s thay i mi qu trnh c nhit .VDK c th kim tra trng thi qu nhit bng lnh ALARM SEARCH [Ech]. D liu trong byte 2,3,4 c ghi thng qua lnh Write Scratchpad [4Eh] v d liu c truyn n DS1820 vi bit LSB ca byte 2, sau khi ghi d liu c th c c li thng qua lnh Read Scratchpad [BEh], v khi c Scratchpad th bit LSB ca byte 0 s c gi i trc Tt c cc byte u c c, nhng ch ghi c byte 2,3 v 4. chuyn gi tr TH v TL t b nh vo EEPROM th cn gi lnh Copy Scratchpad [48h] n DS1820. V d liu t EEPROM cng c th c chuyn vo thanh ghi TH,TL thng qua lnh Recall E2 [B8h]. Time slot khi to, c, v ghi d liu xung DS1820 o Khi to:

Hnh 8 :time slot khi to DS1820GVHD:ThS. V TH NG Page 40

N MN HC 2o c v Vit time slot:

Hnh 9: time slot c v vit d liu xung DS1820 o Cc cch ghp ni Cm bin DS1820 vi Vi iu khin: Ch s dng DS1820 bng cch cp ngun k sinh:

Hnh 10 : ch cp ngun k sinh cho DS1820 Ch cp ngun trc tip cho DS1820:

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N MN HC 2

Hnh 11 : ch cp ngun y cho DS1820 3. Tng quan v LCD: a. Tng quan: Trong nhng nm gn y LCD ang ngy cng c s dng rng ri thay th dn cho cc n LED (cc n LED 7 on hay nhiu on). l v cc nguyn nhn sau: 1. Cc LCD c gi thnh h. 2. Kh nng hin th cc s, cc k t v ho tt hn nhiu so vi cc n LED(v cc n LED ch hin th c cc s v mt s k t). 3. Nh kt hp mt b iu khin lm ti vo LCD lm gii phng cho CPU cng vic lm ti LCD. Trong khi n LED phi c lm ti bng CPU (hoc bng cch no ) duy tr vic hin th d liu. 4. D dng lp trnh cho cc k t v ho.

Hnh 12 : hnh dng LCD

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b. M t cc chn ca LCD:

Hnh 12: M t chc nng cc chn ca LCD

Hnh 13: Bng m lnh ca LCDGVHD:ThS. V TH NG Page 43

N MN HC 2c.Gii thiu LCD 16 x +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 // 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,VEE,RW c nivi mt.

Hnh14 : LCD 16x2 A. Nguyn tc hin th k t trn LCD Mt chng trnh hin th k t trn LCD s i theo bn bc sau:1)Xa ton b mn hnh.2)t ch hin th.3)t v tr con tr (ni bt u ca k t hin th).4)Hin th k t. + Cc bc 3, 4 c th lp li nhiu ln nu cn hin th nhiu k t. + Mi khi thc hin ghi lnh hoc ghi d liu hin th ln LCD cn phikim tra c trc ca chu k trc . V vy, cn phi ch ng phn phithi gian khi ra lnh cho LCD( v d sau khi xa mn hnh sau khong 2ms mi ra lnh khc v thi gian LCD xa mn hnh l 1,64ms). + Ch hin th mc nh s l hin th dch, v tr con tr mc nh s l u dng th nht. 4.Thit b cp nhit - cp nhit cho h thng ta c th s dng dy may so hoc bng n Halozen. -m bo cp nhit ln theo yu cu ca h thng -C kh nng thay i nhit d dng. -Nh vy h thng l p c th s dng thit b cp nhit nh dy May so hoc bng n Halozen.

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Hnh 15: Hnh nh dy May so v bng Halozen thc t

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CHNG III: THIT K PHN CNG H THNGI/ CC MODULE TRONG H THNG 1. Module iu khin L trung tm, l b no ca ton b h thng - Module ny iu khin mi hot ng ca h thng - u vo l dng in p nhn c t module cm bin. - u ra l tn hiu dng s cho php ng, ngt module cpnhit (hoc c th l dng tn hiu tng t).Module ny c vai tr c bit quan trng. 2.Module ci t -Module ci t cho php ci t , iu chnh nhit t nht nh no . -Module cho php tng ,gim nhit t bng cc phm bm -Nhit sau khi ci t c c hin th ln module hinth. 3. Module hin th - Module ny lm tng kh nng giao tip ca h thng vi ngi s dng. - Mi thng tin v nhit c hin th cho ngi s dng quan st nh : nhit t, nhit mi trng , thng bo - Thng tin cn hin th c cp bi module iu khin hay l nhn tn hiu vo t module iu khin. 4. Module cp nhit - Module cp nhit to ra nhit cho h thng p trng. - u vo ca module ny l in p. - u ra ca module l nhit cp cho h thng. - Module ny quyt nh cht lng sn phm. 5. Module khi ngun -H thng mun hot ng c th phi c module ny, t cng ni ln vai tr quan trng ca n. -u vo ca module l in p. -u ra ca module cng l in p cp cho ton b h thng hot ng. 6. Module cm bin - Module ny quyt nh ti chnh xc ca h thng.H thng mun hot ng chnh xc th thng tin ca module ny phi m bo chnh xc , t sai s. - u vo ca module l nhit . - u ra ca module l in p cp cho module iu khin II/ S NGUYN L CA MCH IU KHIN NHIT . Gm c 5 khi chnh:Khi ngun, khi vi s l, khi cm bin nhit , khi hin th LCD, khi cng sut.

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N MN HC 2U8 2 VDD 1 VSS LCD VEE 3 10K p2.5 p2.6 p2.7 VCC VCC R9

4 RS 5 RW 6 EN

16 15

R10

14 13 12 11 10 9 8 7 p 0 .0 p 0 .1 p 0 .2 p 0 .3 p 0 .4 p 0 .5 p 0 .6 p 0 .7

D D D D D D D D

K A

B7 B6 B5 B4 B3 B2 B1 B0

VCC

VCC

VCC 1

R14 2 3 4 5 6 7 8 9 p0.0 p0.1 p0.2 p0.3 p0.4 p0.5 p0.6 p0.7 P1.0 P1.1 P1.2 P1.3 P1.4 P1.5 P1.6 P1.7 39 38 37 36 35 34 33 32 1 2 3 4 5 6 7 8

U7 P0.0/AD0 P0.1/AD1 P0.2/AD2 P0.3/AD3 P0.4/AD4 P0.5/AD5 P0.6/AD6 P0.7/AD7 P2.0/A8 P2.1/A9 P2.2/A10 P2.3/A11 P2.4/A12 P2.5/A13 P2.6/A14 P2.7/A15 21 22 23 24 25 26 27 28 10 11 12 13 14 15 16 17 P3.0 P3.1 P3.2 P3.3 P3.4 P3.5 P3.6 P3.7 p2.0 p2.1 p2.2 p2.3 p2.4 p2.5 p2.6 p2.7 J3 VCC 1 2 3 CON3 VCC R17 560 U10 MOC3020 C6 4 CON2 6 C7 2k2 1 2 Q3 TRIAC R25 1k 1 2

R27

R26 J2

SW1

POWER_LED2

SW2 SW_PB_SPST SW3 SW_PB_SPST

P1.0/T2 P3.0/RXD P1.1/T2-EX P3.1/TXD P1.2 P3.2/INT0 P1.3 P3.3/INT1 P1.4 P3.4/T0 P1.5 P3.5/T1 P1.6 P3.6/WR P1.7 P3.7/RD

VCC SW_PB_SPST C1 RST

19 18 XTAL1 XTAL2 31 9 EA/VPP RST AT89S52

30 ALE/PROG 29 PSEN

30p C2 Y1

VCC VCC

ZTA 30p 47uF RST U9 LM7805C J1 2 1 CON2 12V 1 IN OUT 3 C11 C5 100uF VCC R15 4.7k R16 C3 POWER_LED1

C4 1000uF

III.NGUYN TC HOT NG Khi ngun c nhim v cung cp ngun 5v cho h thng, cung cp ngun kch khi cng sut. Khi vi s l c nhim v iu khin cng nh ly nhit t DS18b20 v v a vo nhit o iu khin khi cng sut. Khi cm bin nhit :C nhim v ly nhit t mi trng v chuyn t tn hiu tng t o sang tn hiu s v chuyn qua vi iu khin qua chun 1 giy.GVHD:ThS. V TH NG Page 47

N MN HC 2 Khi hin th LCD: C nhim v hin th d liu t vi s l. Trong mch hin thi nhit t DS18b20 v gi tr t trc. Khi cng sut: C nhim v iu khin iu khin ng ngt in 220v AC. CHNG IV: THIT K PHN MM H THNG. I/CHNG TRNH ;xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx ;chuong trinh dem xung ngoai su dung counter t0 ;xung dem duoc dua den ngo vao t0 ;xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx MAQUET EQU A ;LUU MA QUET UP BIT P1.1 DOWN BIT P1.0 RELE BIT P3.7 BIENDEM EQU R7 org 0000h CALL KHTAOLCD CLR RELE MOV BIENDEM,#35 CALL HT_HANG1 CALL HT_HANG2 setb p2.0 call delay1s TD: mov dptr,#maLCD MAIN: JNB UP,TANG JNB DOWN,GIAM call nhietdo1820 CALL hextobcd ;chuyen so hex-bcd CALL giaima7doan CALL SOSANH CALL HIENTHI7 CALL DELAY10MS JMP MAIN TANG: ;JNB call call call MODE,$ delay50ms delay50ms delay50ms

;CLR RELE CALL hextobcdGVHD:ThS. V TH NG

;chuyen so hex-bcdPage 48

N MN HC 2CALL giaima7doan CALL HIENTHI7 INC BIENDEM CJNE BIENDEM,#255,MAIN MOV BIENDEM,#0 JMP MAIN ;XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX GIAM: ;JNB MODE,$ call delay50ms call delay50ms call delay50ms ;CLR RELE CALL hextobcd ;chuyen so hex-bcd CALL giaima7doan CALL HIENTHI7 DEC BIENDEM CJNE BIENDEM,#-1,MAIN MOV BIENDEM,#255 JMP MAIN ;XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX SOSANH: MOV A,NHIETDO SUBB A,BIENDEM CJNE A,#2,$+3 JNC THOAT clr RELE RET THOAT: MOV A,BIENDEM SUBB A,NHIETDO CJNE A,#2,$+3 JNC THOAT1 clr RELE RET THOAT1: setb RELE RET ;xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx ;chuyen so hex 1 byte thap tl0 sang so BCD ;xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx hextobcd: mov a,nhietdo ;chuyen byte thap sang AGVHD:ThS. V TH NG Page 49

N MN HC 2mov b,#10 div ab mov 37h,b 37H mov b,#10 div ab mov 36h,b 36H mov 35h,a 35H mov a,BIENDEM mov b,#10 div ab ;chuyen byte thap sang A ;nap 10 vao B ;chia byte thap cho 10 lan thu 1 ;cat BCD HANG TRAM vao o nho ;chia lan thu 2 ;cat BCD HANG CHUC vao o nho ;nap 10 vao B ;chia byte thap cho 10 lan thu 1 ;cat BCD HANG don vi vao o nho

mov 34h,b ;cat BCD HANG don vi vao o nho 37H mov b,#10 div ab ;chia lan thu 2 mov 33h,b ;cat BCD HANG CHUC vao o nho 36H mov 32h,a ret ;xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx ;chuyen so bcd sang ma 7 doan de dkhien led sang ;xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx giaima7doan: MOV A,37H ;lay ma bcd hang don vi MOVC A,@A+DPTR ;lay ma 7 doan dua vao A MOV 27h,A ;cat vao o nho 27h MOV A,36H MOVC A,@a+DPTR MOV 26H,A MOV A,35H MOVC a,@A+DPTR MOV 25H,A MOV A,34H MOVC A,@A+DPTR MOV 24h,A MOV A,33H MOVC A,@a+DPTRGVHD:ThS. V TH NG

;lay ma bcd hang chuc ;lay ma 7 doan dua vao A ;cat vao o nho 21h ;lay ma bcd hang tram ;lay ma 7 doan dua vao A ;cat vao o nho 22h ;lay ma bcd hang don vi ;lay ma 7 doan dua vao A ;cat vao o nho 27h ;lay ma bcd hang chuc ;lay ma 7 doan dua vao APage 50

N MN HC 2MOV 23H,A MOV A,32H MOVC a,@A+DPTR MOV 22H,A RET ;cat vao o nho 21h ;lay ma bcd hang tram ;lay ma 7 doan dua vao A ;cat vao o nho 22h

;xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx ;CHUONG TRINH CON HIEN THI 2 LED ;xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx HIENTHI: MOV A,#8DH CALL KTAO MOV A,25H MOV BYTEOUT,A CALL DATA_BYTE MOV A,#8EH CALL KTAO MOV A,26H MOV BYTEOUT,A CALL DATA_BYTE MOV A,#8FH CALL KTAO MOV A,27H MOV BYTEOUT,A CALL DATA_BYTE MOV A,#0CDH CALL KTAO MOV A,22H MOV BYTEOUT,A CALL DATA_BYTE MOV A,#0CEH CALL KTAO MOV A,23H MOV BYTEOUT,A CALL DATA_BYTE MOV A,#0CFHGVHD:ThS. V TH NG Page 51

N MN HC 2CALL KTAO MOV A,24H MOV BYTEOUT,A CALL DATA_BYTE RET ;xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx $include(tv_18b20.asm) $INCLUDE(TV_LCD20.ASM) $INCLUDE(TV_DELAY.ASM) ;xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx ; Data bytes ;xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx DATAHANG1: DB 'NHIET DO DO: ',099h ;MA 99H LA MA KET THUC HET 1 HANG DATAHANG2: DB 'GIA TRI DAT: ',099h DATAHANG3: DATAHANG4: MALCD: DB '0123456789' End

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N MN HC 2II/M PHNG

LCD1LM016L

R5 R8 R910k 10k 10k

XTAL1

18

XTAL2

9

RST

P0.0/AD0 P0.1/AD1 P0.2/AD2 P0.3/AD3 P0.4/AD4 P0.5/AD5 P0.6/AD6 P0.7/AD7 P2.0/A8 P2.1/A9 P2.2/A10 P2.3/A11 P2.4/A12 P2.5/A13 P2.6/A14 P2.7/A15 P3.0/RXD P3.1/TXD P3.2/INT0 P3.3/INT1 P3.4/T0 P3.5/T1 P3.6/WR P3.7/RD

1 2 3

P0.0 4 P0.1 5 P0.2 6 35.0

29 30 31

PSEN ALE EA

21 22 23 24 25 26 27 28 10 11 12 13 14 15 16 17

1 1

p1.0 1 p1.12 P1.2 3 p1.3 4 p1.4 5 p1.5 6 p1.6 7 p1.7 8

P1.0/T2 P1.1/T2EX P1.2 P1.3 P1.4 P1.5 P1.6 P1.7 AT89C52

U2P3.2 P3.3 3 2 1 VCC DQ GND DS18B20 P3.6 P3.7

7 8 9 10 11 12 13 14

D0 D1 D2 D3 D4 D5 D6 D7

19

39 38 37 36 35 34 33 32

P0.0 P0.1 P0.2

VSS VDD VEE

U1

RS RW E

D1LED-RED

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PHN III: NH GI V KT LUN1. Kt qu thc hin n: Linh kin d kim, tn t linh kin, mch nh gn, c th m rng iu khin nhiu thit b. Chng trnh iu khin x l nhanh, phn gii nhit cao (0.1 C) gip tng chnh xc cho mch o nhit 2. Gii hn ca ti v hng pht trin ca ti: Cha c giao tip t v hin th trn my tnh. Hng pht trin ca ti: Ghp ni nhiu cm bin DS1820 trn BUS 1 dy gim st nhit nhiu im khc nhau trn BUS. 3. Khng nh nhng kt qu t c trong ti nghin cu: Trong n ny, chng em thc hin mch iu khin v o nhit l p trng bng phng php m xung. Nh vy, mi khi iu khin bt k nhit no t 0 dn 255 phi c mt thit b cm nhn nhit trong mch cng sut, thit b ny gi l cm binnhit. Nhm m bo nhit c n nh trong l. Tuy nhin, mi khu vc sn xut hay mi ca sn xut li yu cu vi nhit l khc nhau v th phi c s linh hot trong vic chuyn i nhit . B phn chuyn i trc quan nht l bn phm. T y suy ra cc kt qu m ti ca nhm em thc hin c l: iu khin v o nhit chnh xc v thay i vic ci t s m ban u mt cch linh hot. B phn hin th r rng. Mch in khng phc tp. m bo tt s an ton. D s dng trong thc t. Gi thnh r. Cho php tng hiu sut lao ng. m bo chnh xc.. Tn hao cng sut b, mch c th s dng pin hoc acquy. Mch n gin d thc hin. Mch iu khin v o nhit l p trng l ti thuc n, nghin cu v thc hin tt nn gip sinh vin chng em lm quen vi cch hc t nghin cu , tinh thn hc tp v lm vic theo nhm. Vi vic t nghin cu v thc hin mch iu khin v o nhit , gip sinh vin vn dng cc kin thc hc v s hng dn ca ging vin thc hin tt mch.

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TI LIU THAM KHO.Gio trnh VI X L VI IU KHIN HKTCN THI NGUYN. Trangweb: http://www.picvietnam.com. www.dientuvienam.net www.diendandien.com www.hoiquandientu.com

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