HOC V I EN H AIQUAN K HOA VUK HDINC TI NGHIN CU KHOA HC TEN
ETAING DNG K THUT VI IU KHIN XAY DNG HETH ONG TONG I EU K HI EN NHI
ET OL ONHI ET Nha Trang, Thang 6 Nam 2011 H OC VI EN HAIQUAN K HOA
V UK HDINC TI NGHIN CU KHOA HC TEN ETAING DNG K THUT VI IU KHIN XAY
DNG H ETH ONG T ONG I EU K HI EN NH I ET OL ONHI ET Ngihng dan
:Thng ta Nguyen Xuan PhuHoc vi en thc hi en :Ngoang Hi en Lp KMP10
Nha Trang, Thang 6 Nam 2011 LINOIAU Ngay nay visphat tri en cua
cong nghi ep vii en t, kythuat socac hethong i eu khi en dan dan c
tong hoa. Vinhng kythuat ti en ti en nh vixl , vimach soc ng dung
vao l nh vc i eu khi en, th cac hethong i eu khi enc kh thos, vitoc
oxl cham chap t chnh xac c thay thebang cachethongi eukhi ent ongvi
cacl enhchngtrnhacthi etl ap trc.
Trongquatrnhsanxuatcacnhamay,xnghi ephi ennay,vi ecovakhong chenhi
et ot ong l amot yeu cau het sc can thi et vaquan trong. V
neunambatcnhi etol amvi eccuacachethong,daychuyensanxuatgi uptabi
etctnhtrangl amvi eccuacacyeucau.Vaconhngxl ykp thitranh c nhng h
hong vascocothexay ra. eap ng c yeu cau o vakhong chenhi et otong,
th conhi eu phngphapethchi en,nghi encukhaosatvi i eukhi entoi
nhanthay rang:ngdungvi i eukhi envaovi ecovakhongchenhi etot ongl
aphng phap toiu nhat. c sgi up cua gi ao vi en hng dan Thng ta
NguyenXuanPhuagi uptoi nhi eutrong quatrnhti enhanhthchi enetai ng
dung vi ieu khien xay dng hethong on nh nhiet olonhiet. H oc vien
Ngoang Hi en CHNG I :GII THIU CHUNG V L NHIT 1.1 Gii thiuLin
lmtthitbinbinin nng thnh nhitnngdngtrongcc qu trnh cng ngh khc nhau
nhnung hoc nu luyn cc vt liu, cc kim loi v cc hp kim khc nhau
v.v...- L in c s dng rng ri trong cc lnh vc k thut :+ Sn xut thp
cht lng cao+ Sn xut cc hp kim phe-r+ Nhit luyn v ho nhit luyn+ Nung
cc vt phm trc khi cn, rn dp, ko si+ Sn xut c v kim loi bt- Trong cc
lnh vc cng nghip khc :+Trongcngnghipnhvthcphm,lincdngsy,mvt phm v
chun b thc phm+ Trong cc lnh vc khc, l in c dng sn xut cc vt phm
thutinh, gm s, cc loi vt liu chu la v.v...-L in khng nhng c mt
trong cc ngnh cng nghip m ngy cng
cdngphbintrongisngsinhhothngngycaconngimtcch phongph va dng:Bp
in,ninucm in, bnhunnc in,thit b nung rn, sy in v.v... 1.2 - u im ca
l in so vi cc l s dng nhin liuL in so vi cc l s dng nhin liu c nhng
u im sau :-C kh nng to c nhit cao-m bo tc nung ln v nng sut cao-m
bo nung u v chnh xc do d iu chnh ch in v nhit -Kn-C kh nng c kh ho
v t ng ho qu trnh cht d nguyn liu v vn chuyn vt phm-m bo iu khin
lao ng hp v sinh, iu kin thao tc tt, thit b gn nh1.3 - Nhc im ca l
in-Nng lng in t-Yu cu c trnh cao khi s dng 1.4 - Nguyn l lm vic ca
l in trL in tr lm vic da trn c s khi c mt dng in chy qua mt dydn
hoc vt dn th s to ra mt l-ng nhit theo nh lut Jun-Lenx :Q=I2 RTQ
-Lng nhit tnh bng Jun (J)I - Dng in tnh bng Ampe (A)R - in tr tnh
bng m T - Thi gian tnh bng giy (s)T cng thc trn ta thy in tr R c th
ng vai tr :-Vt nung : Trng hp ny gi l nung trc tip-Dy nung : Khi dy
nung c nung nng n s truyn nhit cho vt nung bng bc x, i lu, dn nhit
hoc phc hp. Trng hp ny gi l nung gin
tip.Trnghpthnhttgpvnchdngnungnhngvtchnhdngn gin ( tit din ch nht,
vung v trn )Trng hp th hai thng gp nhiu trong thc t cng nghip. Cho
nn ni n lintrkhngthkhngcpnvtliulmdynung,bphnpht nhit ca l. Chng II
:Vi iu khin PIC16F877A v Cm bin nhit DS18B20 2.1. c tnh ca vi iu
khin PIC16F877A S dng cng ngh tch hp cao RISC CPU. Ngi s dng c th
lp trnh vi 35 cu lnh n gin. Tt c cc culnh u c thc hin trong mt chu
kngoi tr mt s lnh r nhnh c thc hin trong 2 chu k lnh.Tc hot ng l:
-Xung ng h vo DC 20MHz.Chu k thc hin trong 200ns. B nh chng trnh
flash 8Kx 14words. B nh Ram 368x8bytes. B nh EFPROM 256x8 bytes. -
Kh nng ca b vi iu khin nyKh nng ngt: ln ti 15 ngun ngt trong v ngt
ngoi. Ngn nh Stack c phn chia lm 8 mc.Truy cp b nh bng a ch trc tip
hoc gim tip Ngun khi ng li (POR). B to xung thi gian(PWRT) v b to
dao ng (OST). Bmxungthigian(WDT)vingundaongtrnchipngundao ng (RC)
hotng ng tin cy. C mch chng trnh bo v. Phng thc ct gi SLEEP. C bn
la chn dao ng cng ngh CMOS FLASH/EFPROM ngun mathp , tc cao Thit k
hon ton tnh. Mch chng trnh ni tip c hai chn. X l c/ghi ti b nh chng
trnh.Di in th hot ng rng 2V n 5.5V. Ngun s dng hin ti 2.5mA. Cng
sut tiu th: 180) time = 180; for(j=0;j 130))temperatre =
pre_temperature ; else {pre_temperature = temperature;
putc((char)temperature);} // Xu Ly Nhiet do :if(!flag) { value =
0;
if(temperature == nhietdo) {value = 180; flag = 1;} } else {
if(temperature > nhietdo) value = 180; else if(temperature <
nhietdo){value--;if(value
