LI NI U

T ng ha trong cng nghip v dn dng ngy cng pht trin. B no trong cc h thng t ng ha l cc b iu khin lp trnh PLC. Vic hc v tm hiu v cc b iu khin lp trnh cng nh vn hnh n cho tht tt v hiu qu ang l nhu cu cp thit i vi hu ht hc sinh, sinh vin chuyn ngnh in, in t, t ng ha, c in t

Hin nay, ti liu ging dy v tham kho v k thut iu khin lp trnh PLC cn rt hn ch. Ti liu iu khin lp trnh PLC Siemen S7 200 c bin son nhm gp phn vo vic ging dy v t hc v k thut iu khin lp trnh PLC cho hc sinh, sinh vin ngnh in in t khoa in C Tin, trng Cao ng Hi Dng.

Cu trc chung ca ti liu l mi chng trong cc phn u c v d minh ha c th cho cc mc nhm gip cho hc sinh, sinh vin nm dc tt kin thc c trnh by trong mi mc, ngoi ra cui mi chng c thm mt s cu hi v bi tp hc sinh, sinh vin rn luyn thm.

Trong qu trnh bin son tc gi khng trnh khi thiu st. Rt mong nhn c s gp chn thnh ca qu c gi nhm gip ti liu c hon thin hn. Mi gp xin gi v T in in t, khoa in C Tin, trng Cao ng Hi Dng.

Xin chn thnh cm n!Chng 1

TNG QUAN V IU KHIN

1.1. iu khin l g?

iu khin c nhim v thc hin cc chc nng ring ca mt my mc hay thit b theo mt trnh t hot ng c nh trc ph thuc vo trng thi ca my hay b pht tn hiu.

S iu khin c phn bit da trn cc c im khc nhau:

iu khin theo loi biu din thng tin iu khin nh phn: X l tn hiu u vo nh phn (tn hiu 0 hoc 1) thnh cc tn hiu ra nh phn.

iu khin s: X l cc thng tin s, c ngha cc thng tin c biu din di dng s. iu khin theo loi x l tn hiu iu khin lin kt: Cc trng thi tn hiu cc nh ca ng ra c iu khin vi cc trng thi tn hiu ca ng vo ty thuc vo cc chc nng lin kt (AND, OR, NOT). iu khin trnh t: iu khin vi trnh t theo tng bc, s ng mch ca mt bc sau xy ra ph thuc vo iu kin ng mch tip theo. iu kin ng mch tip theo c th ph thuc vo quy trnh hay thi gian. iu khin khng ng b: Vic iu khin c x l s thay i trc tip ca tn hiu ng vo khng cn tn hiu xung ph (iu khin chm). iu khin ng b: Vic iu khin c x l cc tn hiu ch ng b vi mt tn hiu xung (iu khin nhanh). iu khin theo loi thc hin chng trnh iu khin theo chng trnh kt ni cng: Loi iu khin ny c th c lp trnh c nh, c ngha l khng th thay i c v d nh lp t dy ni c nh hay c th thay i chng trnh thng qua cc u ni (ma trn diode). iu khin kh trnh: Chc nng iu khin c lu gi trong mt b nh chng trnh. Nu s dng b nh c/ghi (RAM), th c th thay i chng trnh m khng cn can thip n phn c kh (iu khin c th lp trnh t do). Nu ngc li l mt b nh ch c (ROM), th chng trnh c th c thay i bng cch thay i b nh (iu khin c th thay i chng trnh c).Hnh 1.1: S cc loi iu khin1.2. Cu trc quy trnh iu khin

Mi s iu khin c chia ra lm 3 b phn hp thnh: Ng vo d liu (ng vo tn hiu), x l d liu (x l tn hiu cng nh cc lin kt) v ng ra d liu (ng ra tn hiu). Dng d liu trong mt s iu khin xy ra t u vo d liu qua phn x l d liu n ng ra d liu.Hnh 1.2: Cu trc chung ca mt quy trnh iu khin

+ Ng vo tn hiu:

+ Giao tip:

+ X l:

+ Khuch i:

+ Ng ra:Bao gm cc loi tn hiu ca cc b pht tn hiu nh nt n, cng tc hnh trnh, cm bin in dung, cm bin in cmTy thuc vo loi iu khin, cc tn hiu c th l nh phn, s hay tn hiu tng t.

Phn ny cn thit, nu tn hiu

Chng 2CM BIN V C CU CHP HNH

2.1. CM BIN2.1.1 Gii thiu

Cc cm bin (Sensor) gip cho PLC pht hin cc trng thi v o lng cc gi tr ca mt qu trnh. Cm bin Logic ch xc nh trng thi ng hay sai ca mt hin tng vt l, cn cm bin lin tc bin i hin tng vt l thnh cc tn hiu o lng c di dng in p hay dng in.

Cc loi cm bin logic c bn thng gp:

Cm bin in cm (Inductive Sensor); Cm bin in dung (Capacitive Sensor); Cm bin quang (Optical Sensor);

Cm bin siu m (Ultrasonic Sensor);

Cm bin tip xc c

Cc loi cm bin tng t c bn thng gp:

Cm bin gc quay/Cm bin v tr;

Cm bin gia tc;

Cm bin nhit ;

Cm bin p sut/Cm bin lu lng;

Cm bin ng sut/bin dng/ lc;

Cm bin nh sng

Hu ht cc cm bin tng t da trn c s thuc tnh nhy cm v in ca cc vt liu v thit b. Kt qu l tn hiu thng i hi x l tn hiu bng cch khuch i dng hay p t c ngng dng v p thch hp.

i khi, cc cm bin tng t cng c gi l cc b chuyn i (Transducer). Bi v chng chuyn i hin tng vo thnh hin tng ra di dng khc, chng hn nh: p sut in p.2.1.2 Ni dy cho cm binKhi mt cm bin pht hin mt s thay i trng thi logic th n phi truyn trng thi thay i ny n PLC. Tiu biu nh s ng hoc ngt dng hin hay in p. Trong mt s trng hp, ng ra cm bin s dng ng mch trc tip cho ti m khng qua PLC. Cc ng ra tiu biu ca cm bin l:

Sinking/Sourcing: ng hoc ngt dng in

Switches: ng hoc ngt in p

Solid State Relays:Chuyn mch AC

TTL (Transistor Transistor Logic): S dng in p 0V - 5V ch th mc logic) 2.1.2.1 Switch

Mt v d n gin nht ca cc ng ra cm bin switch v relay c cho nh hnh 2.1.

Hnh 2.1: Cm bin c ng ra l relay s dng ngun DC v AC2.1.2.2 Ng ra TTL

Ng ra TTL c hai mc in p: 0V tng ng mc thp, 5V tng ng mc cao. in p thc t c th ln hn 0V hoc nh hn 5V mt cht vn c th pht hin ng. Phng php ny rt d b nhiu trong mi trng nh my cho nn n ch c s dng khi cn thit. Cc ng ra TTL thng dng trong cc thit b in t v my tnh. Khi kt ni vi cc thit b khc th mt mch Schimitt trigger thng c s dng ci thin tn hiu (hnh 2.2).

Hnh 2.2: Mch Schimitt trigger

Mch Schimitt trigger s nhn in p ng vo gia 0 5V v chuyn i n thnh 0V hoc 5V. Nu in p nm trong khong 1,5 3,5V th khng chp nhn. Nu mt cm bin c ng ra TTL th PLC phi s dng cc ng vo TTL c gi tr ny. Nu cm bin TTL c s dng trong cc ng dng khc th nn ch dng ng ra cc i ca cm bin (thng khong 20mA).2.1.2.3 Ng ra Sinking/Sourcing

Cc cm bin c ng ra Sinking (rt dng) cho php dng in chy vo cm bin. Cc cm bin c ng ra Sourcing (ngun dng) cho php dng in t cm bin ra i tng c kt ni. hai ng ra ny cn ch l dng in ch khng phi in p. Bng cch s dng dng in th nhiu c loi tr bt.

Khi gii thch v vn sinking hay sourcing th ta nn quy cc ng ra ca cm bin tc ng nh cng tc. Trong thc t ng ra ca cm bin thng l mt transistor chuyn mch. Transistor PNP dng cho ng ra Sourcing v transistor NPN dng cho ng ra Sinking. Khi gii thch cc cm bin ny th khi nim ngun dng thng c dng cho PNP, v rt dng vi NPN. V d cm bin ng ra sinking c cho hnh 2.3.

Hnh 2.3: Cm bin loi NPN (Cm bin rt dng)

Hnh 2.4: Cm bin loi PNP (Cm bin sourcing) cm bin hot ng cn c ngun cung cp (chn L+ v L-). Khi cm bin pht hin i tng th c in p ti cc B ca transistor NPN, transistor chuyn sang trng thi dn v cho php dng chy vo cm bin xung mass (chn L-).Khi khng pht hin i tng th in p ti cc B ca transistor mc thp 0V, transistor khng dn. iu ny c ngha ng ra NPN s khng c dng vo/ra.

Cc cm bin sourcing th ngc vi cc cm bin sinking. N s dng transistor PNP (hnh 2.4). Khi cm bin khng c kch hot th cc B ca transistor gi tr L+, v transistor trng thi ngng dn. Khi cm bin c kch hot th cc B transistor s c t 0V, v transistor cho php dng in chy t cm bin ra ngoi thit b c kt ni.

Hu ht cc cm bin NPN/PNP c kh nng dng n vi ampe v chng c th c s dng ni trc tip vi ti (lun lun kim tra s tay bit chnh xc dng in v in p nh mc).Ch : cn phi nh kim tra dng in v in p nh mc i vi cc cm bin. Khi ni dy cc cm bin cn ch n cc chn ngun. Thng chn ngun k hiu l L+ v COM (chn chung), nhng i khi khng c chn COM m c chn L-. Trong trng hp ny L- l chn chung.

Khi kt ni cc cm bin sourcing vi cc ng PLC, th cn ch phi s dng cc modul ng vo loi sinking. Thng thng cc ng vo PLC thng l loi sinking.

Trong ng dng vi PLC, gim lng dy ni, th cc cm bin hai dy thng c s dng. V d v s ni dy cc cm bin s dng ngun 24VDC vi PLC c ch nh hnh 2.5. Cm bin hai dy c th c s dng cho c hai loi ng vo sourcing hoc ng vo sinking ca PLC.

Hnh 2.5: Kt ni cm bin 2 dy vi ng vo PLCHu ht cc cm bin hin i c c hai ng ra PNP v NPN. Thng thng cm bin loi PNP thng c s dng cho cc ng vo PLC.

Trong cc bn v th cc chn ca cc cm bin NPN v PNP c k hiu v mu sc nh sau: dy mu nu l L+, dy mu xanh dng l L- v ng ra th mu trng i vi sinking v mu en i vi sourcing.

Cn lu l khi tip im trong cm bin sinking ng th ng ra c ni vi COM hoc L-, tip im trong sourcing ng th ng ra ni vi L+.

Hnh 2.6: Kt ni cm bin NPN v PNP vi ng vo PLC2.1.2.4 Ng ra Solid state relay

Cc ng ra Solid state relays ng mch dng in AC. Cc cm bin ny c s dng vi ti ln.

2.1.3 Pht hin i tng

C hai cch c bn pht hin i tng: tip xc v tip cn (proximity). Tip xc c ngha l tip im c kh cn mt lc tc ng gia cm bin v i tng. Tip cn ch bo rng mt i tng ang gn nhng khng yu cu tip xc.

Cc phn sau y s minh ha cc kiu khc nhau ca cc cm bin pht hin s hin din ca cc i tng. Phn ny khng i su vo cc cm bin m ch m t cc nguyn l trong lnh vc ng dng.

2.1.3.1 Chuyn mch tip xc

Chuyn mch tip xc (contact switch ) thng c hai dng l thng h (normally open) v thng ng (normally closed). V ca chng c gia c c th chu c lc c tc ng nhiu ln.

2.1.3.2 Reed Switches

Reed switches th rt ging relay, ngoi tr mt nam chm vnh cu c s dng thay th cun dy. Khi nam chm xa th tip im m, nhng khi nam chm n gn th tip im ng li (hnh 2.7). Cc cm bin ny r tin v chng thng c s dng cho cc mn chn v ca an ton.

Hnh 2.7: Read switch2.1.3.3 Cm bin quang (Optical Sensor)

Cm bin nh sng c s dng gn mt th k qua. Nguyn thy l t bo quang c s dng cho cc ng dng nh c cc track m thanh trn cc hnh nh chuyn ng. Nhng cc cm bin quang hin i th phc tp hn nhiu.

Cc cm bin quang yu cu c c hai b phn l ngun sng (pht) v u thu (detector). Cc u pht (emitter) s pht ra cc tia sng trong vng ph nhn thy v khng nhn thy c s dng LED v diode laser. u thu c cu to l cc diode quang (photodidode) hoc transistor quang (phototransistor). u pht v u thu c t vo v tr i tng khi xut hin s ct ngang hoc phn x li tia sng. Cm bin quang n gin cho hnh 2.8.

Hnh 2.8: Cm bin quang c bnTrong hnh, chm sng c to ra nm bn tri, c hi t qua mt thu knh. i din l u thu, chm tia c hi t bng mt thu knh th hai. Nu chm tia b ngt, th u thu s ch bo mt i tng xut hin. nh sng c to ra di dng xung cm bin c th lc c nh sng bnh thng trong phng. nh sng t u pht c tt v m ti mt tn s t. Khi u thu nhn nh sng, n kim tra m bo chc chn rng n c cng tn s. Nu nh sng ang nhn c ti tn s ng th chm tia khng b ngt. Tn s dao ng nm trong phm vi KHz. Ngoi ra vi phng php tn s th cc cm bin c th c s dng vi cng sut thp hn v khong cch di hn. u pht c th bt u t mt im trc tip ti u thu, y cn gi l ch t phn x. Khi tia sng b ngt, th i tng c pht hin. Cm bin ny cn hai b phn ring (hnh 2.9a). S xp t ny lm vic tt vi cc i tng chn sng v phn x vi u pht v u thu c tch ring vi khong cch ln n c trm mt.

Hnh 2.9: Cc loi cm bin quang khc nhauu thu v u pht tch ring lm tng vn v bo tr v yu cu v s thng hng. Mt gii php khc l u pht v u thu c t chung trn mt v. Nhng iu ny yu cu nh sng t phn x tr v (hnh 2.9b,c). Cc cm bin ny ch tt cho cc i tng ln vi khong cch mt vi met. Trong hnh, u pht pht mt chm tia sng. Nu nh sng b di tr v t gng phn x th hu ht s tr v u thu. Khi mt i tng ngt chm tia gia u pht v gng phn x th chm tia s khng t phn x tr v u thu v cm bin c tc ng. Mt vn ri ro cho cc cm bin ny l cc i tng t phn x li chm tia sng tt. gii quyt th s dng bin php phn cc nh sng ti u pht (bng b lc), v sau sau s dng mt b lc phn cc ti u thu.

2.1.3.4 Cm bin in dung (Capacitive Sensor)

Cc cm bin in dung c th pht hin hu ht cc vt liu vi khong cch vi cm. Cng thc biu din mi quan h in dung: Vi C: in dung (Faradays)

: Hng s in mi

A: Din tch bn cc

D: Khong cch gia cc bn cc

Trong cm bin, din tch cc bn cc v khong cch gia chng l c nh. Nhng hng s in mi ca khng gian xung quanh chng s thay i khi cc vt liu c mang n gn cm bin. Minh ha hnh 2.10.

B mt ca cm bin in dung c hnh thnh bi hai in cc kim loi ng tm ca mt t in. Khi mt i tng n gn b mt nhn bit n i vo vng in trng ca cc in cc v thay i in dung trong mch dao ng. Kt qu l b to dao ng bt u dao ng. Mch trigger c bin ca b dao ng v khi t n mc xc nh th trng thi ng ra s thay i. Khi i tng ri khi cm bin th bin ca b dao ng gim, cm bin chuyn v trng thi bnh thng.

Hnh 2.10: Cm bin in dungCc cm bin ny lm vic tt i vi cht cch in (nh cht do) c hng s in mi cao (lm tng in dung). Hng s in mi cng ln th khong cch hot ng cng cao. V d khi hiu chnh ng th cht lng trong thng cha c th c pht hin c d dng. Tuy nhin, chng cng lm vic tt i vi kim loi.

Cc cm bin thng c ch to vi cc vng (khng phi bn cc) theo hnh 2.11. Trong hnh, hai vng kim loi nm bn trong l cc in cc ca t in, nhng vng ngoi th ba c thm vo b s thay i. Nu khng c vng b ny th cm bin s rt nhy cm vi bi bm, du v cc cht khc dnh trn cm bin.

Hnh 2.11: B mt nhn bit ca cm bin in dungPhm vi v chnh xc ca cc cm bin c xc nh bi kch thc ca chng. Cc cm bin ln c th c ng knh vi centimeter. Ci nh c ng knh nh hn mt centimeter v c phm vi nh hn nhng chnh xc hn.

2.1.3.5 Cm bin in cm (Inductive Sensor)

Cc cm bin in cm s dng dng in cm ng pht hin i tng l kim loi. Cm bin in cm s dng mt cun dy to mt t trng tn s cao c cho hnh 2.12. Nu c mt i tng l kim loi n gn lm thay i t trng, th s c dng chy vo i tng. Dng chy ny to ra mt t trng mi ngc vi t trng ban u. Kt qu l n lm thay i t cm ca cun dy trong cm bin. Bng cch o t cm, cm bin c th xc nh mt i tng kim loi n gn.

Cc cm bin ny s pht hin bt k kim loi no, khi cn pht hin cc loi kim loi th cc cm bin a kim loi thng c s dng.

Hnh 2.12: Cm bin tip cn in cmKhi i tng kim loi i vo vng in t trng, th dng in xoy truyn vo i tng. iu ny lm tng ti trong cm bin, lm gim bin ca in t trng. Mch trigger gim st bin dao ng khi t n mc nh trc th n chuyn i trng thi ng ra ca cm bin. Khi i tng di chuyn khi cm bin, th bin dao ng tng ln. Khi n gi tr nh trc th mch trigger chuyn i trng thi ng ra tr v iu kin bnh thng.

Hnh 2.13: Cm bin tip cn in cmCc cm bin c th pht hin cc i tng cch xa vi centimeter. Nhng hng ca i tng c th l bt k nh hnh 2.14. T trng ca cc cm bin khng bc bao ph xung quanh u ca cun dy ln hn. Bng cch lp thm v bc kim loi th t trng s nh hn, nhng hng ca i tng nhn bit c ci thin hn.

Hnh 2.14: Cm bin c bc v khng bc v kim loi2.1.3.6 Cm bin siu m (Ultrasonic sensor)

Cm bin siu m pht ra m thanh trn ngng nghe bnh thng 16kHz. Thi gian c yu cu m thanh di chuyn n mc tiu v phn hi tr v t l vi khong cch mc tiu. C hai loi cm bin l:

Tnh in (electrostatic): S dng hiu ng in dung. Phm vi ln v bng thng rng hn nhng nhy cao hn vi i tng m t.

p in (piezoelectric): Da vo phn t p in thch anh.

Cc cm bin ny c th rt hiu qu cho cc ng dng nh o mc cht lng trong thng cha.

2.1.3.7 Hiu ng Hall (Hall Effect)

Cc cng tc hiu ng Hall c bn l cc transistor c th chuyn mch bi t trng. Cc ng dng ca chng th rt ging vi reed switch, nhng v chng ch l cht bn dn nn chng ph hp vi cc chuyn ng. Cc my mc t ng ha thng s dng chng thc hin khi ng v pht hin v tr dng.

2.1.3.8 Lu lng (Fluid Flow)

Hnh 2.15: Xc nh lu lng dng chy vi cm bin tip cn cmChng ta c th thay th cc cm bin phc tp bng cc cm bin n gin. Hnh 3.15 cho thy mt phao kim loi trong mt knh hnh nn. Tc dng chy tng p lc y phao ln trn. Dng hnh nn ca phao m bo v tr ca cht lng t l vi tc dng chy. Mt cm bin tip cn in cm c th c nh v n pht hin khi phao t n cao no , v h thng t n tc dng chy nh.

2.2 C cu chp hnh

2.2.1 Gii thiu

C cu chp hnh c s dng bin i nng lng in thnh chuyn ng c hc.

2.2.2 Solenoid

Solenoid l c cu chp hnh thng dng nht. Nguyn l hot ng c bn l s di chuyn li st (piston) trong cun dy (hnh 2.16). Bnh thng piston c gi bn ngoi cun dy. Khi cun dy c cp in, cun dy sinh ra t trng ht piston v ko n vo trung tm ca cun dy. ng dng quan trng nht ca solenoid l iu khin cc van kh nn, thy lc v kha ca xe.

Hnh 2.16: SolenoidCn ch l cc cun cm c th to ra in p gai nhn v c th cn cc b gim sc. Mc d vy hu ht trong cc ng dng cng nghip c in p thp v dng in nh mc, chng c th c kt ni trc tip vi cc ng ra ca PLC. Hu ht cc solenoid cng nghip s dng ngun cung cp 24Vdc v dng nh mc mt vi trm mA.

2.2.3 Van iu khin (VALVE)

Dng cht lng v kh c th c iu khin bng cc van iu khin solenoid. V d van iu khin solenoid c cho hnh 2.17.

Hnh 2.17: Mt Solenoid iu khin van 5 ca 2 v trCc loi van c lit k di y. Theo tiu chun, thut ng n-ca ch nh s lng kt ni cc ng vo v ra ca van. Trong mt vi trng hp c ca x kh ra. Vic thit k thng ng/thng m cho bit iu kin van khi mt ngun cp.

Van 2 ca, 2 v tr thng ng (van 2/2): Cc van ny c 1 ca vo v mt ca ra. Khi mt ngun cung cp th v tr thng ng. Khi c ngun cung cp, th van m cho php dng kh hay cht lng chy qua. Cc van ny c s dng cho php dng chy.

Van 2 ca, 2 v tr thng m (van 2/2): Cc van ny c mt ca vo v mt ca ra. Khi mt ngun th m cho php dng chy. Khi c ngun, van ng. Cc van ny c s dng ngt dng chy.

Van 3 ca, 2 v tr thng ng (van 3/2): Cc van ny c ca vo, ca ra v ca x kh. Khi mt ngun th ca ra c ni vi ca x kh. Khi c ngun th ca vo c ni vi ca ra. Cc van ny c s dng cho cc cylinder tc ng n.

Van 3 ca, 2 v tr thng m (van 3/2): Cc van ny c ca vo, ca ra v ca x kh. Khi mt ngun th ca vo c ni vi ca ra. Khi c ngun th van ni ca ra vi ca x kh. Cc van ny c s dng cho cc cylinder tc ng n.

Van 3 ca, 2 v tr a nng (van 3/2): Cc van ny c 3 ca. Mt trong cc ca hot ng nh l ca vo hoc ca ra, v c ni n mt trong hai ca khc khi mt ngun hoc c ngun. Cc van ny c th c s dng lm chuyn hng dng chy, hoc chn ngun qua li. Van 4 ca, 2 v tr (van 4/2): Cc van ny c 4 ca, 1 vo, 2 ra v 1 ca x kh. Khi c ngun van ni cc ca vo vi cc ca ra v ngc li. Cc van ny c s dng vi cc cylinder tc ng kp.

Van 5 ca, 2 v tr (van 5/2): Cc van ny c 5 ca, 1 vo, 2 ra v 2 ca x kh.

Van 4 ca, 3 v tr (van 4/3): Cc van ny c 4 ca, 1 vo, 2 ra v 1 x. trng thi bnh thng (khng c ngun nng lng) th cc ca vo/ra u b chn. Van ny c s dng iu khin v tr cc cylinder.

Van 5 ca, 3 v tr (van 5/3): Van ny c 5 ca, 1 vo, 2 ra v 2 ca x. Tng t nh van 4/3, van ny c s dng iu khin v tr cc cylinder.

K hiu ca cc van c cho hnh 3.18. Khi s dng trong cc bn v th v trng thi khng c cp ngun nng lng. Mi tn ch ng dn dng chy n cc v tr khc. Biu tng tam gic nh ch ca x kh. Bng 2.1: K hiu cc van iu khin bng kh nn v solenoidLoi vanK hiu

iu khin bng kh nniu khin bng solenoid

Van 2 ca, 2 v tr

Van 3 ca, 2 v tr

Van 4 ca, 2 v tr

Van 5 ca, 2 v tr

Van 4 ca, 3 v tr

Van 5 ca, 3 v tr

Khi chn la van, cn ch mt s chi tit sau:

Kch thc ng: Ca vo v ra theo tiu chun NPT (national pipe thread).

Tc dng chy: Tc dng chy cc i thng c cung cp cho cc van thy lc.

p sut hot ng: p sut hot ng cc i phi c ch bo. Mt vi van c yu cu p sut ti thiu hot ng.

Ngun in: Cc cun dy solenoid yu cu c cung cp mt in p v dng in c nh (AC hoc DC).

Thi gian p ng: y l thi gian van ng/m hon ton. Thi gian tiu biu cho cc van nm trong phm vi t 5ms n 150ms.

V bc: V bc cho cc van c xp theo loi:

Loi 1 hoc 2: S dng trong nh, yu cu bo v chng nc. Loi 3: S dng ngoi tri, chng bi bm v ma gi.

Loi 3R hoc 3S hoc 4: Chng nc v bi.

Loi 4X: Chng nc, bi v s n mn.

2.2.4 Xy lanh (CYLINDER)

Cylinder s dng p lc kh hoc cht lng to lc/chuyn ng tuyn tnh (hnh 2.19). Trong hnh, dng cht lng c bm vo mt pha ca cylinder lm dch chuyn piston v pha cn li. Cht lng pha ny c thot t do. Lc tc dng ln cylinder t l vi din tch b mt ca piston.

Cng thc tnh lc:

Vi P: p sut thy lc

F: Lc y piston

A: Din tch piston

Cylinder tc ng n yu cu cung cp lc khi dui ra v s dng l xo co v. Cn cylinder tc ng kp th cung cp lc c hai pha.

Hnh 2.19: Mt ct ca cylinder thy lcCc cylinder t thng c s dng trong iu khin kh nn. Trn u ca piston c mt mnh nam chm. Khi n di chuyn n v tr gii hn th cc cng tc reed switch s pht hin ra.

Hnh 2.30: Cylinder tc ng n v cylinder tc ng kp2.2.5 ng c

ng c l c cu chp hnh thng thng, nhng i vi ng dng cho iu khin nh phn th c im ca n khng quan trng. iu khin logic tiu biu ca cc ng c l ng ct in cho n. Cc ng c c dng in nh c th u trc tip vo cc ng ra ca PLC, cn i vi cc ng c cng sut ln th s dng relay hay contactor hoc b khi ng ng c.2.2.6 Cc c cu chp hnh khc

Ngoi cc c cu chp hnh k trn cn c nhiu loi c cu chp hnh khc nhau trong iu khin logic. Mt s c cu chp hnh thng c s dng relay v contactor. Ngoi ra c mt s c cu chp hnh khc:

L nhit: Thng c iu khin bng relay, ng v ct in gi nhit nm trong mt phm vi no . n bo: n bo c s dng cho hu ht cc my mc ch bo trng thi my v cung cp thng tin cho ngi vn hnh. Hu ht cc n bo c dng in thp v c kt ni trc tip n PLC. Ci/chung bo: Ci hay chung bo c th c s dng cho cc my mc khng c gim st hoc ang b nguy him. Chng thng c ni trc tip vi cc ng ra ca PLC. Chng 3

B iu khin lp trnh PLC Siemen S7-2003.1 Gii thiu chung

PLC S7 200 l thnh vin nh nht ca gia nh thit b iu khin lp trnh SIMATIC S7 ca hng Siemen (CHLB c). Mi loi CPU S7 200 u bao gm u vo v u ra c vai tr ging nh mt CPU.

u vo v u ra (I/O) l cc im iu khin h thng. u vo gim st cc thit b giao tip, chng hn nh cng tc v cm bin tng t. u ra iu khin cc thit b khc, chng hn nh ng c v van iu khin.Cng lp trnh dng kt ni vi thit b lp trnh, ng thi cung cp mt gii php kt ni PLC vi cc thit b khc, chng hn nh mn hnh hin th.

Hinh 3.1: PLC S7 200 vi thit b vo/ra

C 6 loi CPU S7 200 (CPU 221, CPU 222, CPU 224, CPU 224XP, CPU 224Xpsi v CPU 226) vi hai cu hnh cung cp ngun cho tng loi.Bng 3.1: Cc loi ngun cung cp cho PLC S7 - 200

Trong bng ct u tin m t kiu, ct th 2 cho bit kiu ngun cung cp in cho tng loi CPU, ct th 3 cho bit kiu u vo, ct th 4 cho bit kiu u ra. V d, Mt CPU kiu 222 AC/DC/Relay cho bit ngun cung cp cho PLC l ngun AC, u vo c cung cp ngun DC, u ra kiu chuyn mch Relay.

PLC S7 200 bao gm nhiu chng loi CPU, cung cp mt lot cc tnh nng h tr trong vic thit k cc h thng t ng ha c chi ph hiu qu. Lu rng cc CPU 224Xpsi c u ra k thut s loi rt dng (sinking) nhng cc tnh nng ca n cng tng t nh i vi CPU 224XP.

Bng 3.2: H PLC S7 200 CPU 22X

Ty thuc vo loi CPU, CPU S7 200 c cung cp mt trong hai li ngun in 24VDC hay 120 240 VAC. V d, CPU 221 DC/DC/DC c cung cp mt ngun in mt chiu 24 VDC, CPU 222 AC/DC/Relay c cung cp mt ngun in xoay chiu 120 n 240 VAC.

Hnh 3.2:Cung cp ngun cho PLC S7 200 loi CPU DC/DC/DC v AC/DC/Relays Nt chn ch v iu chnh u vo Analog

PLC S7 200 c mt cng tc chuyn i ch c ba v tr chn v tr lm vic khc nhau ca PLC: RUN, STOP v TERM RUN: Cho php PLC thc hin chng trnh trong b nh. PLC S7-200 s ri khi ch RUN v chuyn sang ch STOP nu trong my c s c, hoc trong chng trnh gp lnh STOP. STOP: Cng bc PLC dng chng trnh ang chy v chuyn sang ch STOP. ch STOP, PLC cho php hiu chnh, np, xa mt chng trnh. TERM: Cho php ngi dng t my tnh quyt nh chn mt trong hai ch lm vic cho PLC hoc RUN hoc STOP.S mt ngoi b iu khin lp trnh PLC S7-200 CPU 224 nh hnh 1.1.

Hnh 3.3: B iu khin lp trnh PLC S7-200 CPU 224 M t cc n bo trn PLC S7-200 CPU 224:

SF (n ): n SF sng bo hiu h thng b li. RUN (n xanh): Cho bit PLC ang ch lm vic v thc hin chng trnh c np vo trong b nh chng trnh ca PLC. STOP (n vng): n vng STOP sng ch nh PLC ang ch dng. Dng chng trnh ang thc hin li. Ix.x (n xanh): n xanh cng vo ch nh trng thi tc thi ca cng (I0.0-I0.7 v I0.0-I0.5). n ny bo hiu trng thi ca tn hiu theo gi tr logic ca cng vo. Qz.z (n xanh): n xanh cng ra ch nh trng thi tc thi ca cng (Q0.0-Q0.7 v Q1.0-Q1.1). n ny bo hiu trng thi ca tn hiu ra theo gi tr logic.Thng tin v h PLC S7-200 CPU 22x c cho nh bng 1.1

Cng truyn thng:

PLC S7-200 CPU s dng cng truyn thng ni tip RS-485 vi jack ni 9 chn phc v cho vic ghp ni vi thit b lp trnh hoc vi cc trm PLC khc. Tc truyn cho my lp trnh kiu PPI l 9600 baud. Tc truyn cung cp ca PLC theo kiu t do l t 300 baud n 38400 baud.

ghp ni PLC S7-200 vi my lp trnh PG720 (hng Siemen) hoc vi cc loi my lp trnh thuc h PG7xx c th s dng mt cp ni thng qua MPI.

Ghp ni PLC S7-200 vi my tnh PC qua cng RS-232 cn c cp ni PC/PPI Multi-Master vi b chuyn i RS-232/RS-485, v qua cng USB ta c cp USB/PPI Multi-Master.

Card nh, pin, clock (CPU 221, CPU 222)

PLC S7-200 cung cp nhiu bin php m bo cho chng trnh ngi dng, d liu chng trnh v cu hnh d liu c duy tr nh sau:

Mt t in vi in dung ln cho php nui b nh RAM sau khi b mt ngun in cung cp. Ty theo loi CPU m thi gian lu tr c th ko di nhiu ngy. Chng hn PLC S7-200 CPU 224 l khong 100 gi.

Vng nh EFPROM cho php lu chng trnh, cc vng nh c ngi dng chn cha vo EFPROM v cu hnh lu ch.

Cho php gn thm Pin nui RAM v cho php ko di thm thi gian lu tr d liu, c th l n 200 ngy k t khi mt ngun in. Ngun ca Pin s c ly sau khi t in x ht.

Card nh: c s dng lu tr chng trnh. Chng trnh cha trong card nh bao gm: Program block, data block, system block, cng thc (recipes), d liu o (data logs), v cc gi tr cng bc (force values).

Card pin: Dng m rng thi gian lu tr cc d liu c trong b nh. Ngun pin c t ng chuyn sang khi t trong PLC cn. Pin c th s dng n 200 ngy.

Card clock/ Battery module: ng h thi gian thc (Real-time clock) cho PLC S7-200 CPU 221/222 v ngun pin nui ng h v lu d liu. Thi gian s dng n 200 ngy.

Hnh 3.3: Hnh dng cc module Bin tr chnh gi tr analog:Hai bin tr ny c s dng nh hai ng vo analog cho php iu chnh cc bin cn phi thay i v s dng trong chng trnh.3.1.2 Module m rng ca PLC S7-200Cc CPU tch hp sn cc ng vo v ng ra s, chng hn PLC S7-200 CPU 224 AC/DC/Relay c sn 14 ng vo v 10 ng ra. Tuy nhin trong thc t, xut pht t yu cu iu khin cn nhiu hn s ng vo/ra, c s dng tn hiu analog hay cc yu cu v truyn thng, ni mng cc PLCm ta phi gn thm vo CPU cc khi m rng (Expansion module) c cc chc nng khc nhau.

Bng 1.2: Cc module m rng cho PLC S7-200

Digital Module

Input8 DC In8 AC In16 DC In

Output4 DC Out 4 Relay Out8 Relay Out

T hp4 DC In/4 DC Out8 DC In/8 DC Out16 DC In/16 DC Out32 DC In/32 DC Out

4 DC In/4 Relay Out8 DC In/8 Relay Out16 DC In/16 Relay Out32 DC In/32 Relay Out

Analog Module

Input4 Analog In8 Analog In4 Thermocouple In

2 RTD In2 RTD In

Output2 Analog Out4 Analog Out

T hp4 Analog In/ 4 Analog Out

Intelligent Module

PositionModemPROFIBUS-DP

EthernetEthernet IT

Cc Module khc

AS-InterfaceSIWAREX MS

Analog Module

Khi ng vo tng t AI (Analog Input): Tn hiu analog ng vo c th l tn hiu in p hoc dng in. Ty thuc tn hiu cn c la chn module ph hp.

Hin c cc module 4AI, 8AI. i vi tn hiu analog c to ra bi thermocouple (cp nhit) v RTD th s dng cc module o nhit tng t.

Khi ng ra tng t AO (Analog Output): Tn hiu analog ng ra c th l in p hoc dng in.

in p ra: - 10VDC ti + 10VDC, tng ng vi gi tr s t -32000 ti + 32000.

Dng in ra: 0 20mA tng ng vi gi tr t 0 32000.

Intelligent Module

Master trong mng AS-Interface: Giao tip AS-I (Actuator Sensor Interface) hay giao tip actuator/sensor l h thng kt ni cho cp qu trnh thp nht trong h thng t ng ha nhm ti u vic kt ni cm bin v c cu chp hnh vi thit b t ng ha. Vi module CP243-2 cho php kt ni mng AS-Interface vo PLC S7-200 v ng vai tr l master.

Kt ni vo mng PROFIBUS-DP: Cc PLC S7-200 c th kt ni vo mng Profibus hot ng nh mt DP Slave nh vo khi m rng EM 277. Vic s dng EM 277 cho php PLC S7-200 c th kt ni truyn thng vi cc thit b trong mng Profibus nh: PLC S7-300, S7-400, mn hnh iu khin

Kt ni vo mng Ethernet: c th kt ni PLC S7-200 vo mng Industrial Ethernet th cn c khi CP 243-1. y l khi truyn thng cho php cc PLC S7-200 c th c cu hnh, lp trnh, chun on t xa qua Ethernet nh phn mm STEP 7 Micro/WIN. Gip cho cc PLC S7-200 c th giao tip vi cc PLC S7-200 khc, S7-300 hay S7-400 qua Ethernet. Cc CPU c th s dng l h CPU 22x.

C th thc hin cu hnh cho cc CPU vo mng Ethernet nh vo Wizard (Menu Tools Ethernet wizard).

Internet Technology: Khi m rng CP 243-1 IT cho php cc PLC S7-200 c th thc hin cc gim st hay thay i qua trnh duyt Web t mt PC c ni mng. Cc thng bo chun on c th gi qua Email t mt h thng. S dng cc chc nng IT cho php trao i cc tp tin d liu vi cc my tnh hay cc h thng iu khin khc. Mi mt khi CP 243-1 IT ch nn kt ni cho 2 PLC S7-200.

Modem module: Cho php kt ni trc tip S7-200 vo ng dy in thoi, v cung cp truyn thng gia S7-200 v Step 7 Micro/WIN.

Vi cng c Modem Expansion wizard cho php thit lp mt modem xa hoc kt ni PLC S7-200 vi mt thit b xa qua modem.

Function Module

L cc khi chc nng thc hin cc chc nng c bit nh iu khin v tr (Position module), cn (SIWREX MS).

Position module: Module v tr c s dng iu khin tc v v tr ca ng c bc (Step motor) hoc ng c Servo (Servo motor). Vi cng c Position Control wizard trong phn mm Step 7 Micro/WIN thit lp cu hnh cho module iu khin v tr. Module iu khin v tr thng c s dng l EM 253.

SIWAREX MS: L module cn a nng v linh hot, n c s dng i vi cc h thng cn hoc o lc s dng PLC S7-200.

Kh nng truyn thng ca PLC S7-200 nh hnh 1.3

Hnh 1.3: Kh nng truyn thng ca PLC S7-2001.2 Mn hnh iu khin

Trong cc yu cu iu khin c gim st th i vi PLC S7-200 chng ta c th gn thm cc mn hnh iu khin v gim st. Hin c cc loi l: mn hnh hin th dng vn bn (Text Display), mn hnh iu khin bng bn phm (Operator panel) v mn hnh cm ng (Touch Panel).

- Bng iu khin hin th dng vn bn (Text Display): Cc mn hnh ny c gi thnh thp, cho php ngi vn hnh my c th xem, gim st bng cc dng vn bn v thay i cc thng s hay ch hot ng ca h thng iu khin bng cc phm trn bng iu khin. Gm cc loi l TD100C, TD200C, TD200, TD400C.

Cc bng iu khin ny c th c thit lp cc thng bo v nt nhn iu khin d dng bng cng c Text Display wizard (Menu Tools Text Display Wizard) trong Step 7 Micro/WIN.

Hnh 1.4: Bng iu khin hin th dng vn bnOperator Panel v Touch Panel: Cc mn hnh c ng dng iu khin v gim st cc my mc, thit b nh. Thi gian thit lp cu hnh v vn hnh nhanh vi phn mm WinCC Flexible. Gm cc loi: OP 73micro, TP 177micro (mn hnh thay th mn hnh trc TP 070/TP 170micro).

Hnh 1.5: Mn hnh OP 73micro v TP 177micro1.3 Cc vng nh

B nh ca PLC S7-200 c chia ra lm cc vng nh nh trong bng 1.3.

Bng 1.3: Cc vng nh v c im ca PLC S7-200M tCPU 221CPU 222CPU 224CPU 224XPCPU 226

Kch thc chng trnh ngi dng4 Kb4 Kb8 Kb12 Kb16 Kb

Kch thc d liu2 kB2 kB8 kB10 Kb10Kb

Vng m vo sI0.0 I15.7I0.0 I15.7I0.0 I15.7I0.0 I15.7I0.0 I15.7

Vng m ra sQ0.0 Q15.7Q0.0 Q15.7Q0.0 Q15.7Q0.0 Q15.7Q0.0 Q15.7

Ng vo AnalogAIW0 AIW30AIW0 AIW30AIW0 AIW62AIW0 AIW62AIW0 AIW62

Ng ra AnalogAQW0 AQW30AQW0 AQW30AQW0 AQW62AQW0 AQW62AQW0 AQW62

Vng nh bin (V)VB0 VB2047VB0 VB2047VB0 VB8191VB0 VB10239VB0 VB10239

Vng nh cc b (L)LB0 LB63LB0 LB63LB0 LB63LB0 LB63LB0 LB63

Vng nh bit (M)M0.0M31.7M0.0 M31.7M0.0 M31.7M0.0 M31.7M0.0 M31.7

Vng nh c bit

Ch c (SM)SM0.0 S M179.7

SM0.0 SM29.7SM0.0S M179.7

SM0.0 SM29.7SM0.0S M179.7

SM0.0 SM29.7SM0.0S M179.7

SM0.0 SM29.7SM0.0S M179.7

SM0.0 SM29.7

Timer

Retentive On-delay

1ms

10ms

100ms

On/Off delay

1ms

10ms

100ms

256 (T0T255)

T0, T64

T1T4T65 T68

T5T31T69 T95

T32, T96T33T36T97T100T37T63T101T255256 (T0T255)

T0, T64

T1T4T65 T68

T5T31T69 T95

T32, T96

T33T36T97T100

T37T63T101T255256 (T0T255)

T0, T64

T1T4T65 T68

T5T31T69 T95

T32, T96

T33T36T97T100

T37T63T101T255256 (T0T255)

T0, T64

T1T4T65 T68

T5T31T69 T95

T32, T96

T33T36T97T100

T37T63T101T255256 (T0T255)

T0, T64

T1T4T65 T68

T5T31T69 T95

T32, T96

T33T36T97T100

T37T63T101T255

CounterC0C255C0C255C0C255C0C255C0C255

B m tc caoHC0HC5HC0HC5HC0HC5HC0HC5HC0HC5

Bit iu khin trnh t (S)S0.0S31.7S0.0S31.7S0.0S31.7S0.0S31.7S0.0S31.7

Thanh ghi AccuAC0AC3AC0AC3AC0AC3AC0AC3AC0AC3

Jumps/Lable02550255025502550255

Call/Subroutine063063063063063

Interrupt routines01270127012701270127

nh sn xung (positive/negative)256256256256256

PID loops0707070707

PortPort 0Port 0Port 0Port 0, Port 1Port

1.4 Quy c a ch trong PLC S7-2001.4.1 Truy xut theo bit

truy xut a ch theo dng Bit chng ta xc nh vng nh, a ch ca Byte v a ch ca Bit. V d:

Hnh 1.6: Truy xut vng nh m u vo I theo bit

Trong hnh 1.6 l bn vng nh ca b m d liu u vo I (Process Image Input). Bn ca cc vng nh khc cng c cu trc tng t nh vy. Bit thp nht l bit 0 nm bn phi v bit cao nht l bit 7 nm bn tri. Do chng ta hon ton c th khai bo tng t nh v d trn, chng hn nh: Q1.0, V5.2, M0.1,. Dung lng ca cc vng nh ph thuc vo loi CPU m chng ta s dng.

1.4.2 Truy xut theo byte (8 bit)

Khi truy xut d liu theo byte, chng ta xc nh vng nh, v th t ca byte cn truy xut. V d:

Hnh 1.7: Truy xut vng nh V theo dng byte

Tng t, ta khai bo cho cc vng nh khc, chng hn nh: IB3, MB2, QB5

1.4.3 Truy xut theo word

Hnh 1.8: Truy xut vng nh V theo dng word

Lu :

i vi tn hiu tng t (Analog) th chng ta ch c mt dng truy xut duy nht l truy xut theo word. iu ny l do mi tn hiu tng t s ng vi mt gi tr s nguyn 16 bit. V d: AIW0, AIW2, AQW0,

Khi truy xut a ch theo word th hai word lin k nhau bt buc cch nhau 2 byte. V d ta cn cha 2 d liu dng s interger vo vng bin V, th d liu th nht gi s cha vo VW20 th word k tip lu d liu th hai l VW22.

1.4.4 Truy xut theo 2 word (Double word = 32 bit)

Khi truy xut vng nh 32 bit, tng ng vi 4 byte. Trong gm c word thp, word cao v byte thp, byte cao.

V d: VD100

Hnh 1.9: Truy xut vng nh V theo dng Double wordBng tm tt vic truy xut cc vng nh theo bit, byte, word v double word c cho nh bng .

Bng: Cch truy xut cc vng nh theo a ch bit, byte, word, double wordCch truy xutCPU 221CPU 222CPU 224CPU 224XPCPU 226

Bit I0.0 15.70.0 15.70.0 15.70.0 15.70.0 15.7

Q0.0 15.70.0 15.70.0 15.70.0 15.70.0 15.7

V0.0 2047.70.0 2047.70.0 8191.70.0 10239.70.0 10239.7

M0.0 31.70.0 31.70.0 31.70.0 31.70.0 31.7

SM0.0 165.70.0 299.70.0 549.70.0 549.70.0 165.7

S0.0 31.70.0 31.70.0 31.70.0 165.70.0 165.7

T0 2550 2550 2550 2550 255

C0 2550 2550 2550 2550 255

L0.0 63.70.0 63.70.0 63.70.0 63.70.0 63.7

Byte IB0 150 150 150 150 15

QB0 150 150 150 150 15

VB0 20470 20470 81910 102390 10239

MB0 310 310 310 310 31

SMB0 1650 2990 5490 5490 549

SB0 310 310 310 310 31

LB0 630 630 630 630 63

AC0 30 30 30 2550 255

KB (Constant)KB (Constant)KB (Constant)KB (Constant)KB (Constant)KB (Constant)

Word IW0 140 140 140 140 14

QW0 140 140 140 140 14

VW0 20460 20460 81900 102380 10238

MW0 300 300 300 300 30

SMW0 1640 2980 5480 5480 548

SW0 300 300 300 300 30

T0 2550 2550 2550 2550 255

C0 2550 2550 2550 2550 255

LW0 620 620 620 620 62

AC0 30 30 30 30 3

AIW0 300 300 620 620 62

AQW0 300 300 620 620 62

KW (Constant)KW(Constant)KW(Constant)KW(Constant)KW(Constant)KW(Constant)

Double Word ID0 120 120 120 120 12

QD0 120 120 120 120 12

VD0 20440 20440 81880 102360 10236

MD0 280 280 280 280 28

SMD0 1620 2960 5460 5460 546

SD0 280 280 280 280 28

LD0 600 600 600 600 60

AC0 30 30 30 30 3

HC0 50 50 50 50 5

KD (Constant)KD (Constant)KD (Constant)KD (Constant)KD (Constant)KD (Constant)

Tm li, v c bn chng ta c bn dng truy xut d liu nh trn. Trong mi yu cu iu khin c th chng ta s chn truy xut theo dng no.

Kim tra trng thi ca cc tn hiu c to ra t cc ngoi vi ni vi ng vo s nh nt n, cm bin, cng tc hnh trnh th chn truy xut l bit, trong trng hp ny th chn a ch ng vo tng ng c kt ni v d I0.0, I0.5, I0.1

Xut tn hiu ra cc c cu chp hnh nhn tn hiu nh phn nh relay, n bo, van t tnh th s chn truy xut l bit, trong trng hp ny th chn a ch ng ra tng ng c kt ni v d nh Q0.0, Q0.2, Q1.0

Nhn tn hiu t cc cm bin to ra tn hiu analog nh cm bin nhit , p sut, m th s dng a ch word, v d nh AIW0, AIW2, AIW4

Xut tn hiu analog ra cc c cu chp hnh nhn tn hiu analog nh ng vo analog bin tn, van t lth s dng a ch word, v d AQW0, AQW2, AQW4

Trong qu trnh thc hin chng trnh cn lu tr thng tin dng s 16 bit nh m s sn phm (s nguyn 16 bit) th truy cp a ch word, cn dng 32 bit nh nhit , p sut (s thc) th truy cp a ch double word

1.5 X l chng trnh trong PLC S7-200

PLC S7-200 thc hin c v ghi d liu theo logic iu khin trong chng trnh lin tc theo chu k. Hot ng ca PLC S7-200 theo trnh t nh sau:

c trng thi cc ng vo thng qua b m u vo

PLC S7-200 s dng cc ng vo ny thc hin logic iu khin theo chng trnh c lu tr trong n. D liu lun c cp nht khi chng trnh c thc hin.

Xut d liu ra ng ra.

Hnh 1.10 l mt s n gin ch mi quan h gia s in v PLC S7-200. Cc nt n khi ng/dng ng c c kt ni vi ng vo. Trng thi ca cc ng vo ty thuc vo nt n. Cc trng thi ca ng vo s quyt nh trng thi ca ng ra. Ng ra c kt ni vi contactor. Ty theo trng thi ca ng ra m contactor c in hay mt in v tng ng ng c s hot ng hay dng.

Hnh 2.10: iu khin ng vo/ra Hnh 2.11: Chu k qut ca PLC S7-200

Chu k qut trong PLC S7-200PLC S7-200 thc hin mt lot cc nhim v theo chu k. Vic thc hin cc nhim v theo chu k c gi l chu k qut (Scan Cycle). Hnh 1.12 l v d mt chu k qut. PLC S7-200 thc hin cc nhim v sau trong mt chu k qut:

c ng vo: PLC S7-200 sao chp trng thi ca cc ng vo vt l vo b m ng vo.

Digital inputs: Mi chu k qut bt u bng cch c gi tr hin hnh cc ng vo s v sau ghi cc gi tr ny vo cng m ng vo.

Analog inputs: PLC S7-200 khng cp nht cc ng vo analog t cc module m rng nu l chu k qut bnh thng tr khi c kch hot khu lc cc ng vo analog. B lc analog c cung cp cho php ta c mt tn hiu n nh hn. C th cho php b analog mi im ng vo analog. Khi mt ng vo analog c kch hot b lc, S7-200 cp nht ng vo analog mi mt ln trong chu k qut v lu tr gi tr lc. Gi tr lc c cung cp mi khi truy cp ng vo analog. Khi b lc analog khng c kch hot, S7-200 c gi tr ng vo analog t module m rng mi ln chng trnh truy xut ng vo analog.

Thc hin theo logic iu khin trong chng trnh: PLC S7-200 thc hin cc lnh trong chng trnh v lu gi tr vo vng nh.

Khi thc hin chu k qut, S7-200 thi hnh t lnh u tin cho n lnh cui cng. Cc lnh truy cp I/O tc th cho php ta truy xut ngay lp tc cc ng vo v ng ra khi thc hin chng trnh cng nh chng trnh ngt (interrupt routine).

Nu c s dng cc ngt trong chng trnh (chng trnh ngt c gi bi cc yu cu ngt) th n khng c thc hin chu k qut bnh thng. N c thc hin khi c s kin ngt (c th xy ra ti bt k thi im no trong chu k qut).

X l bt k yu cu truyn thng no: PLC S7-200 thi hnh bt k nhim v c yu cu cho truyn thng.

Trong giai on x l thng tin ca chu k qut, S7-200 x l bt k thng tin no nhn c t cng truyn thng hoc t cc module truyn thng (intelligent I/O module).

Thc hin t chun on CPU: S7-200 t kim tra m bo phn firmware, b nh chng trnh, v bt k cc module m rng no cng ang lm vic ng.

Trong giai on ny, S7-200 kim tra cho hot ng thch hp ca CPU v trng thi ca bt k module m rng no.

Xut ra ng ra: Cc gi tr c lu trong vng m ng ra s c xut ra cc ng ra vt l.

Ti cui mi chu k, S7-200 xut cc gi tr c lu trong b m ng ra n cc ng ra s. (Cc ng ra analog th c cp nht ngay lp tc, khng ph thuc vo chu k qut).

Vic thc hin chng trnh cn ty thuc vo S7-200 ang ch STOP hay ch RUN. ch RUN th chng trnh c thc hin, cn ch STOP th chng trnh khng c thc hin.

5 KT NI DY GIA PLC V THIT B NGOI VI

5.1 Kt ni dy gia PLC v cc thit b ngoi vi Vic kt ni dy gia PLC vi ngoi vi rt quan trng. N quyt nh n vic PLC c th giao tip c vi thit b lp trnh (my tnh) cng nh h thng iu khin c th hot ng ng theo yu cu c thit k hay khng. Ngoi ra vic ni dy cn lin quan n an ton cho PLC cng nh h thng iu khin. 5.1.1 Gii thiu CPU 224 v cch kt ni vi thit b ngoi vi S b mt ca b iu khin lp trnh S7-200 CPU 224 c cho nh hnh 5.1.

Hnh 5.1: B iu khin lp trnh S7-200 CPU 224 cho b iu khin lp trnh ny hot ng c th ngi s dng phi kt ni PLC vi ngun cung cp v cc ng vo ra ca n vi thit b ngoi vi. Mun np chng trnh vo CPU, ngi s dng phi son tho chng trnh bng cc thit b lp trnh hoc my tnh vi phn mm tng ng cho loi PLC ang s dng v c th np trc tip vo CPU hoc copy chng trnh vo card nh cm vo rnh cm card nh trn CPU ca PLC. Thng thng khi lp trnh cng nh khi kim tra hot ng ca PLC th ngi lp trnh thng kt ni trc tip thit b lp trnh hoc my tnh c nhn vi PLC. Nh vy, h thng iu khin khin bng PLC hot ng cng nh lp trnh cho n, cn phi kt ni PLC vi my tnh cng nh cc ng vo ra vi ngoi vi. 5.1.2 Kt ni vi my tnh i vi cc thit b lp trnh ca hng Siemens c cc cng giao tip PPI th c th kt ni trc tip vi PLC thng qua mt si cp. Tuy nhin i vi my tnh c nhn cn thit phi c cp chuyn i PC/PPI. C 2 loi cp chuyn i l cp RS-232/PPI Multi-Master v cp USB/PPI Multi-Master. Cp RS-232/PPI multi-masterHnh dng ca cp v cng tc chn ch truyn c cho hnh 5.2.

Hnh 5.2: Hnh dng cp RS-232/PPI v cc chuyn mch trn cpTy theo tc truyn gia my tnh v CPU m cc cng tc 1,2,3 c v tr thch hp. Thng thng i vi CPU 22x th tc truyn thng t l 9,6 Kbaud (tc cng tc 123 c t theo th t l 010). Ty theo truyn thng l 10 Bit hay 11 Bit m cng tc 7 c t v tr thch hp. Khi kt ni bnh thng vi my tnh th cng tc 7 chn ch truyn thng 11 Bit (cng tc 7 t v tr 0). Cng tc 6 cp RS-232/PPI Multi-Master c s dng kt ni port truyn thng RS-232 ca mt modem vi S7-200 CPU. Khi kt ni bnh thng vi my tnh th cng tc 6 c t v tr Data Comunications Equipment (DCE) (cng tc 6 v tr 0). Khi kt ni cp PC/PPI vi mt modem th port RS-232 ca cp PC/PPI c t v tr Data Terminal Equipment (DTE) (cng tc 6 v tr 1). Cng tc 5 c s dng t cp RS-232/PPI Multi-Master thay th cp PC/PPI hoc hot ng ch Freeport th t ch PPI/Freeport (cng tc 5 v tr 0). Nu kt ni bnh thng l PPI (master) vi phn mm STEP 7 Micro/Win 3.2 SP4 hoc cao hn th t ch PPI (cng tc 5 v tr 1). S ni cp RS-232/PPI Multi-Master gia my tnh v CPU S7-200 vi tc truyn 9,6 Kbaud c cho nh hnh 5.3.

Hnh 5.3: Kt ni my tnh vi CPU S7-200 RS-232/PPI Multi-Master Cp USB/PPI multi-masterHnh dng ca cp c cho hnh 5.4.

Hnh 5.4: Hnh dng cp USB/PPICch thc kt ni cp USB/PPI Multi-Master cng tng t nh cp RS-232/PPI Multi-Master. s dng cp ny, phn mm cn phi l STEP 7-Micro/WIN 3.2 Service Pack 4 (hoc cao hn). Cp ch c th c s dng vi loi CPU22x hoc sau ny. Cp USB khng c h tr truyn thng Freeport v download cu hnh mn TP070 t phn mm TP Designer. 5.1.3 Ni ngun cung cp cho CPU Ty theo loi v h PLC m cc CPU c th l khi ring hoc c t sn cc ng vo v ra cng nh mt s chc nng c bit khc. Hu ht cc PLC h S7-200 c nh sn xut lp t cc khu vo, khu ra v CPU trong cng mt v hp. Nhng ngun cung cp cho cc khu ny hon ton c lp nhau. Ngun cung cp cho CPU ca h S7-200 c th l: Xoay chiu:

20.....29 VAC, f = 47...63 Hz85...264 VAC, f = 47...63 Hz Mt chiu:

20,4 ... 28,8 VDC

Hnh 5.5: S ni ngun cung cp cho CPUa. Cp ngun cho CPU 2xx loi DC/DC/DC

b. Cp ngun cho CPU 2xx loi AC/DC/RLY c th nhn bit vic cp ngun cho CPU, khi vo, khi ra s ta cn c vo cc ch s i km theo CPU. Cc m s km theo CPU 2xx c th c nh sau: CPU 2xx DC/DC/DC: Ngun cp cho CPU l DC, ngun cho ng vo l DC, ngun cp cho ng ra l DC. CPU 2xx AC/DC/Relay: Ngun cp cho CPU l AC, ngun cho ng vo l DC, ng ra l Relay c th cp ngun l DC hoc AC. 5.1.4 Kt ni vo/ra s vi ngoi vi Cc ng vo, ra ca PLC cn thit iu khin v gim st qu trnh iu khin. Cc ng vo v ra c th c phn thnh 2 loi c bn: s (Digital) v tng t (analog). Hu ht cc ng dng s dng cc ng vo/ra s. Trong bi ny ch cp n vic kt ni cc ng vo/ra s vi ngoi vi, cn i vi ng vo/ra tng t s trnh by chng x l tn hiu analog. i vi b iu khin lp trnh h S7-200, hng Siemens a ra rt nhiu loi CPU vi in p cung cp cho cc ng vo ra khc nhau. Ty thuc tng loi CPU m ta c th ni dy khc nhau. Vic thc hin ni dy cho CPU c th tra cu s tay km theo ca hng sn xut. 5.1.4.1 Kt ni cc ng vo s vi ngoi vi Cc ng vo s ca PLC c th c ch to l mt khi ring, hoc kt hp vi cc ng ra chung trong mt khi hoc c tch hp trn khi CPU. Trong trng hp no cng vy, cc ng vo cng phi c cung cp ngun ring vi cp in p ty thuc vo loi ng vo. Cn lu trong mt khi ng vo cng nh cc ng vo c tch hp sn trn CPU c th c cc nhm c cung cp ngun c lp nhau. V vy cn lu khi cp ngun cho cc nhm ny. Ngun cung cp cho cc khi vo ca h S7-200 c th l: Xoay chiu: 15...35 VAC, f = 47...63 Hz; dng cn thit nh nht 4mA 79...135 VAC, f = 47...63 Hz; dng cn thit nh nht 4mA Mt chiu:15 ... 30 VDC; dng cn thit nh nht 4mAS mch in bn trong ca mt s ng vo c cho nh hnh 5.6a,b.

Hnh 5.6: a) Mch in ca 1 ng vo s s dng ngun cung cp DC

b) Mch in ca 1 ng vo s s dng ngun cung cp AC Ty theo yu cu m c th quyt nh s dng loi ng vo no. Ng vo DC in p DC thng thp do an ton hn. p ng ng vo DC rt nhanh. in p DC c th c kt ni vi nhiu phn t trong h thng in. Ng vo AC: Ng vo AC yu cu cn phi c thi gian. V d i vi in p c tn s 50 Hz phi yu cu thi gian n 1/50 giy mi nhn bit c. Tn hiu AC t b nhiu hn tn hiu DC, v vy chng thch hp vi khong cch ln v mi trng nhiu (t). Ngun AC kinh t hn.

Tn hiu AC thng c s dng trong cc thit b t ng hin hu. i vi cc ng vo s, khi kt ni vi ngoi vi, ngoi tr cc trng hp c bit th thng thng mi mt ng vo c kt ni vi mt b to tn hiu nh phn nh: nt nhn, cng tc, cm bin tip cn.... Hnh 5.7a,b,c minh ha cch kt ni dy cc ng vo PLC vi cc b to tn hiu nh phn khc nhau. Cn lu n cc loi cm bin khi kt ni vi cc ng vo PLC. Trong v d hnh 5.7a c 3 ng vo, mt l nt nhn thng h, hai l tip im ca relay nhit, v ba l cm bin tip cn vi ng ra l relay. C ba b to tn hiu ny c cung cp bi mt ngun 24VDC. Khi tip im h hoc cm bin pht tn hiu 0 th khng c in p ti cc ng vo. Nu cc tip im c ng li hoc cm bin pht tn hiu 1 th ng vo c cp in.

Hnh 5.7: Kt ni ng vo vi ngoi vi a. Nt nhn v cm bin c ng ra l relay ni vi ng vo loi sinkingb. Nt nhn v cm bin loi PNP ni vi ng vo loi sinking c. Nt nhn v cm bin loi NPN ni vi ng vo loi sourcingi vi cc ng vo ra ca CPU 214 DC/DC/DC, CPU 224 AC/DC/Relay theo s tay c kt ni nh hnh 5.10 v hnh 5.11. 5.1.4.2 Kt ni cc ng ra s vi ngoi vi Cc ng ra ca PLC c th c ch to l mt khi ring, hoc kt hp vi cc ng ra chung trong mt khi hoc c tch hp trn khi CPU. Trong trng hp no cng vy, cc ng ra cng phi c cung cp ngun ring vi cp in p ty thuc vo loi ng ra. Cn lu trong mt khi ra cng nh cc ng ra c tch hp sn trn CPU c th c cc nhm c cung cp ngun c lp nhau. V vy cn lu khi cp ngun cho cc nhm ny. Ngun cung cp cho cc khi ra ca h S7-200 c th l: Xoay chiu:20...264 VAC , f = 47...63 Hz;

Mt chiu:5...30 VDC i vi ng ra r le; 20.4 ... 28.8 VDC i vi ng ra transistor; Cc khi ra tiu chun ca PLC thng c 8 n 32 ng ra theo cng loi v c dng nh mc khc nhau. Ng ra c th l r le, transistor hoc triac. R le l ng ra linh hot nht. Chng c th l ng ra AC v DC. Tuy nhin p ng ca ng ra r le chm, gi thnh cao v b h hng sau vi triu ln ng ct. Cn ng ra transistor th ch s dng vi ngun cung cp l DC v ng ra triac th ch s dng c vi ngun AC. Tuy nhin p ng ca cc ng ra ny nhanh hn. S mch in bn trong ca cc ng ra c cho nh hnh 5.8. Cn ch khi thit k h thng c c hai loi ng ra AC v DC. Nu ngun AC ni vo ng ra DC l transistor, th ch c bn k dng ca chu k in p c s dng v do in p ra s b gim. Nu ngun DC c ni vi ng ra AC l triac th khi c tn hiu cho ng ra, n s lun lun c in cho d c iu khin tt bng PLC.

Hnh 5.8: Mch in bn trong ca cc loi ng ra khc nhaua) Ng ra transistor b) Ng ra relay c) Ng ra triaci vi cc ng ra s, khi kt ni vi ngoi vi, ngoi tr cc trng hp c bit th thng thng mi mt ng ra c kt ni vi mt i tng iu khin nhn tn hiu nh phn nh: n bo, cun dy r le, chung bo . . . Hnh 5.9 minh ha cch kt ni dy cc ng ra PLC vi cc c cu chp hnh. Hnh 5.9a l mt v d cho cc khi ra s dng 24Vdc vi mass chung. Tiu biu cho loi ny l ng ra transistor. Trong v d ny cc ng ra c kt ni vi ti cng sut nh l n bo v cun dy relay. Quan st mch kt ni ny, n bo s dng ngun cung cp l 24Vdc. Nu ng ra .6 mc logic 1 (24Vdc) th dng s chy t ng ra .6 qua n H1 v xung Mass (M), n sng. Nu ng ra mc logic 0 (0V), th n H1 tt. Nu ng ra .4 mc logic 1 th cun dy r le c in, lm tip im ca n ng li cung cp in 220 Vac cho ng c. Hnh 5.9b l mt v d ng ra relay s dng ngun cp l 24 Vdc, v hnh 5.9c l v d ng ra triac s dng ngun xoay chiu 24 Vac. Mt ch quan trng khi kt ni cc ng ra cn tra cu s tay khi ng ra hin c c c thng tin chnh xc trnh c nhng s c ng tic xy ra. Hnh 5.10 l v d ca CPU 214 vi ngun cung cp DC, ng vo DC v ng ra DC c ni dy vi ngoi vi (trch t s tay S7-200 Programmable Controller System Manual). Ta nhn thy mi mt nhm ng vo cng nh mt nhm ng ra v CPU c cung cp ngun ring l 24 Vdc. Ngoi ra trn khi CPU cn c ngun ph 24 Vdc (n 280 mA) c th c s dng cung cp cho cc cm bin hoc khi m rng. Hnh 5.9: Kt ni dy ng ra PLC vi c cu chp hnh

Hnh 5.10: S ni dy CPU 214 DC/DC/DC vi ngun v ngoi vi

Hnh 5.11: S ni dy CPU 224 AC/DC/Relay vi ngun v ngoi vi 5.2 Kim tra vic kt ni dy bng phn mm Mt cng vic quan trng cho ngi lp t v vn hnh l bit c cc kt ni ca cc ng vo/ra vi ngoi vi c ng hay khng trc khi np chng trnh iu khin vo CPU. Hoc khi mt h thng ang hot ng bnh thng nhng mt s c h hng xy ra th cc phn ngoi vi no b h v pht hin n bng cch no. Cc phn mm cho cc b iu khin bng PLC thng c trang b thm cng c kim tra vic kt ni dy ng vo/ra vi ngai vi. Trong phn mm Step 7 Micro/Win (phn mm lp trnh cho h S7-200) c trang b thm phn ny l mc Status Chart. s dng phn mm tt hn hy xem thm chng Phn mm STEP 7-Micro/Win v ngn ng lp trnh. 5.2.1 Status Chart Chng ta c th s dng Status Chart c, ghi hoc cng bc cc bin trong chng trnh theo mong mun. c th m Status Chart, ta nhp p chut vo biu tng Status Chart trong ca s Navigation Bar trn mn hnh Step 7-Micro/Win32 hoc vo mc View Component Status Chart. 5.2.2 Gim st v thay i bin vi Status Chart Hnh 5.9 ch mt v d v cch s dng Status Chart. c hay ghi cc bin chng ta thc hin theo cc bc sau: Bc 1: u tin trong ct Address ta nhp vo a ch hay tn k hiu ca mt bin trong chng trnh ng dng m mun gim st hoc iu khin, sau n ENTER. Lp li bc ny cho tt c cc bin c thm vo biu . Bc 2: Nu bin l 1 Bit (v d:I, Q, hoc M), th kiu bin t ct Format l bit. Nu bin l mt byte, word, hay double word th chn ct Format v nhp p chut tm kiu bin mong mun.

Bc 3: xem gi tr hin hnh ca cc bin trong PLC trong biu , hy nhp chut vo biu tng hoc chn Debug Chart Status. chp c mt gi tr ca cc bin ti thi im nhp chut s dng Debug Single Read hoc nhp chut vo biu tng . Bc 4: dng vic gim st th nhp chut vo biu tng hoc chn Debug Chart Status. Bc 5: thay i gi tr ca mt bin hoc nhiu bin, hy nhp gi tr mi vo ct New Value cho cc bin mong mun v nhp chut vo biu tng hoc chn Debug Write All ghi tt c cc gi tr ny vo cc bin tng ng trong CPU.

Hnh 5.13: V d v status chart

5.2.3 Cng bc bin vi Status Chart Trong mt s trng hp cn thit phi p buc mt ng vo hoc mt ng ra hoc bt k mt bin no trong chng trnh theo mt gi tr mong mun cho ph hp vi hon cnh hat ng hin ti ca h thng hoc kim tra cc li xy ra trong h thng iu khin, ta c th s dng cng c cng bc bin (Force).

cng bc bin trong Status Chart vi mt gi tr xc nh, thc hin cc bc sau:

Bc 1: Chn mt trong ct Address, vo a ch hay hay tn ca bin cn cng bc.

Bc 2: Nu bin l 1 Bit (v d:I0.0, Q0.1), th kiu bin ct Format lun lun l bit. Nu bin l mt byte, word, hay double word th chn ct Format v nhp p chut tm kiu bin mong mun.

Bc 3: cng bc bin vi gi tr hin hnh, trc tin hy c gi tr hin hnh trong PLC bng cch nhp chut vo biu tng hoc chn Debug Chart Status.

Nhp hoc cun cha gi tr hin hnh mun cng bc. Nhp chut vo biu tng hoc chn Debug Force trn v tr gi tr hin hnh cng bc bin gi tr . Bc 4: cng bc mt gi tr mi cho mt bin, nhp gi tr vo ct New Value v nhp chut vo biu tng hoc chn Debug Force . Bc 5: xem gi tr hin hnh ca tt c cc bin b cng bc, kch chut vo biu tng Read All Forced hoc chn Debug Read All Forced. Bc 6: cho tt c cc bin tr li trng thi bnh thng, hy kch chut vo biu tng Unforce All hoc chn Debug Unforce All.Mun g b cng bc mt bin, hy chn bin mong mun v nhp chut vo biu tng hoc chn Debug Unforce. 5.2.4 ng dng Status Chart trong vic kim tra kt ni dy trong S7-200 Sau khi kt ni dy ngai vi vi cc ng vo/ra ca PLC, vic k tip l kim tra li kt ni dy ny pht hin ra cc li kt ni. Mt cng c hu hiu l s dng Status Chart. Lu khi kim tra kt ni dy: i vi ng vo Cc ng vo no c ni vi cc tip im thng ng hay tn hiu c mc logic 1 th cc ng vo c in p v n bo trng thi cc ng vo sng. Khi quan st trong status chart, ta s nhn thy cc gi tr ny c mc logic 1. Vic kim tra cc ng vo nn thc hin ln lt cho tng ng vo theo bng kt ni dy vo/ra vi ngoi vi. C ngha l mi ln ta ch thay i trng thi ca mt b to tn hiu (nt nhn, cm bin,...) v quan st trng thi ca ng vo c kt ni vi n trong status chart.

Ghi chp li cc kt ni b sai v sa cha. i vi ng ra trng thi bnh thng khi cha c chng trnh th tt c cc ng ra ca PLC u mc logic 0 (khng c in p) v n bo trng thi cc ng ra u tt. Vic kim tra ni dy ng ra nn thc hin ln lt tng ng ra theo bng kt ni dy bng cch cho ng ra mun kim tra ln mc lodic 1 trong status chart v quan st trng thi ca ngoi vi c kt ni tng ng. Nu ngoi vi tng ng c in chng t n c kt ni ng cn ngc li kt ni sai.

Ghi chp li cc kt ni sai v sa cha.

5.3 Cu hi v bi tp BT 5.1: Ng vo ca PLC c th ng in cho cun dy r le iu khin mt ng c c khng? Cc khi vo v khi ra ng vai tr g trong vic giao tip gia PLC v thit b ngai vi? BT 5.2: Cc khi m rng ng vo/ra c li ch g? BT 5.3: iu g xy ra nu mt ng ra AC c cp ngun DC? BT 5.4: Mt khi vo/ra m rng ca PLC h S7-200 loi EM223 gm c 8 ng vo DC/8 ng ra rle. Cc ng vo c ni vi 4 nt nhn, 2 ng ra c ni vi mt rle trung gian s dng ngun 24VDC dng ng mch cho mt contactor 220VAC iu khin ng c 3 pha 220V/380V. 2 ng ra c ni vi 2 n bo 220VAC bo chiu quay ca ng c. 2 ng ra c s dng cho cc van kh nn 24 VDC. Hy v s ni dy cc ng vo v ra ny vi ngoi vi theo yu cu. BT 5.5: Hy thit k mt d n c iu khin bng PLC. Trc khi t hng, cn phi phc tho vic ni dy c bn v chn la cc loi PLC hoc khi vo/ra c cc ng vo/ra tng ng. Cc thit b c s dng ni vi cc ng vo gm c: 2 cng tc hnh trnh, 1 nt nhn thng h, 1 nt nhn thng ng v mt tip im nhit. Ng ra s iu khin mt van solenoid 24VDC, mt n bo 110VAC v mt ng c 220VAC/50HP. Hy la chn loi PLC hoc mt khi vo/ra ph hp v kt ni dy theo yu cu t ra. BT 5.6: Hy phc tho s ni dy cho cc ng ra PLC theo yu cu c lit k di y:

- Mt van kh nn c 2 cun dy solenoid - Mt n bo 24VDC - Mt n bo 120 VAC - Mt ng c cng sut thp 12 VDC. 6. Phn mm Micro/Win v ngn ng lp trnh6.1 Ci t phn mm STEP 7-Micro/WIN STEP 7-Micro/WIN l mt phn mm lp trnh cho h PLC S7-200. Hin phin bn ang c s dng l STEP 7-Micro/Win V4.0 Service Pack 6. 6.1.1 Yu cu h iu hnh v phn cng My tnh c nhn PC, mun ci t c phn mm STEP 7-micro/WIN phi tha mn nhng yu cu sau y: Microsoft Windows 2000 Service Pack 3 hoc cao hn, Windows XP Home, hoc Windows XP Professional. C t nht 350 MB a cng cn trng S dng ch ci t font ch nh phn gii mn hnh ti thiu l 1024x768 pixels. Nu cha c cp kt ni my tnh vi PLC S7-200 th ta vn c th son tho chng trnh ch offline v kim tra hot ng ca chng trnh vi mt phn mm m phng. truyn thng vi S7-200, ta cn mt trong cc phn cng sau: PC/PPI Cable kt ni CPU S7-200 vi PC qua cng USB PC/PPI Cable kt ni CPU S7-200 vi PC qua cng RS232 (COM1 hoc COM2) CP card (Communications processor) v cp MPI (multipoint interface).

EM241 modem

CP243-1 hoc CP243-1 IT Ethernet

6.1.2 Ci t phn mm

Thc hin theo cc bc sau:

1. ng tt c cc ng dng

2. Chn a CD STEP 7-Micro/Win vo a CD-Rom. Chng trnh s c t ng ci t. Ta cng c th khi ng chng trnh ci t bng cch nhp p chut vo file Setup.exe trn CD. 3. Sau s nhn c dn dn tng bc cc ch dn thao tc tip theo trn mn hnh v hon thnh cng vic ci t.

4. Khi ci t xong, hp thoi set PG/PC Interface t ng xut hin. Kch Cancel kt thc.

5. Ta cn khi ng li my hon tt vic ci t.

Sau khi ci t xong c th bt u son tho chng trnh nh phn mm STEP 7 Micro/WIN bng cch nhp p chut vo biu tng STEP 7 MicroWIN trn mn hnh. Ch : Khi ci t phin phn STEP 7-Micro/WIN V4.0 Sevice Pack 6 th trc tin ta cn phi uninstall phin bn c v sau mi ci t c phin bn ny. Sau khi download ta nhp p chut vo file STEP7-MicroWIN_V40_SP6.exe v thc hin theo cc bc sau:

Bc 1: Uninstall phin bn STEP 7-Micro/WIN V4.0 bng cng c Control panel trong Window (Menu StartSettingsControl panelAdd or Remove program).

Bc 2: Khi ng li my tnh

Bc 3: Ci t STEP 7-Micro/WIN V4.0 Service Pack (SP6) bng cch nhp p chut vo file STEP7-MicroWIN_V40_SP6.exe.

6.2 Cc phn t c bn trong chng trnh PLC S7-200 Cc phn t c bn trong mt chng trnh PLC S7-200 l:

1. Chng trnh chnh (main program)

2. Chng trnh con (subroutine)

3. Chng trnh ngt (interrupt rountine)

4. Khi h thng (system block)

5. Khi d liu (data block)

6.2.1 Chng trnh chnh OB1 (main program)

y l phn khung ca chng trnh, cha cc lnh iu khin chng trnh ng dng. Vi mt s chng trnh iu khin nh, n gin chng ta c th vit tt c cc lnh trong khi ny. Chng trnh ng dng c x l bt u t chng trnh chnh, cc lnh c x l ln lt t trn xung di v ch mt ln mi vng qut. Trong S7-200 chng trnh c cha trong khi OB1.

6.2.2 Chng trnh con SUB (subroutine) Cc lnh vit trong chng trnh con ch c th c x l khi chng trnh con c gi (Call) t chng trnh chnh, t mt chng trnh con khc hoc t mt chng trnh ngt. S dng chng trnh con khi chng ta mun phn chia nhim v iu khin. Mi mt chng trnh con vit cho mt nhim v nh hoc khi c cc yu cu iu khin tng t nhau (v d: iu khin bng ti 1, iu khin bng ti 2) th chng ta ch cn to ra chng trnh con mt ln v c th gi ra nhiu ln t chng trnh chnh. S dng chng trnh con c mt s u im sau:

Chng trnh iu khin c chia theo nhim v iu khin nn c cu trc r rng, rt thun tin cho vic chnh sa hay kim tra chng trnh.

Gim thi gian vng qut ca chng trnh. CPU khng phi lin tc x l tt c cc lnh ca chng trnh m ch x l chng trnh con khi c lnh gi tng ng. Chng trnh con cho php gim cng vic son tho khi c cc yu cu iu khin tng t nhau.

6.2.3 Chng trnh ngt INT(interrupt routine)

Chng trnh ngt c thit k s dng cho mt s kin ngt c nh ngha trc. Bt c khi no s kin ngt xc nh xy ra, th S7-200 thc hin chng trnh ngt.

Chng trnh ngt khng c gi bi chng trnh chnh m theo s kin ngt xy ra. Chng trnh ngt s ch c x l mi khi s kin ngt xy ra.

6.2.4 Khi h thng (system block)

System block cho php ta cu hnh cc ty chn phn cng khc nhau cho S7-200.

6.2.5 Khi d liu (data block)

Data block lu tr cc gi tr bin khc nhau (vng nh V) c s dng trong chng trnh. Gi tr ban u ca cc d liu c th nhp vo trong khi d liu.

6.3 Ngn ng lp trnh

c th son tho chng trnh cho cc PLC S7-200, chng ta dng phn mm Step7 MicroWin. V cng ging nh PLC ca cc hng khc, chng ta c 3 dng son tho thng dng l dng LAD, FBD v STL. Vic chn dng son tho no vit chng trnh iu khin l do ngi dng ty chn.

6.3.1 Dng hnh thang : LAD (Ladder logic)

dng son tho ny chng trnh c hin th gn ging nh s ni dy mt mch trang b in dng cc relay v contactor. Chng ta xem nh c mt dng in t mt ngun in chy qua mt chui cc tip im logic ng vo t tri qua phi ti ng ra. Chng trnh iu khin c chia ra lm nhiu Network, mi mt Network thc hin mt nhim v nh v c th. Cc Network c x l ln lt t trn xung di v t tri sang phi.

Cc phn t ch yu dng trong dng son tho ny l:

Tip im khng o: Tip im o: Ng ra (hoc trng thi ni ca bin): Cc hp chc nng (Box): cc chc nng c biu din dng hp nh cc php ton s hc, nh thi, b m

V d:

Dng son tho ny c mt s u im:

D dng cho nhng ngi mi bt u lp trnh

Biu din dng ha d hiu v thng dng

Lun lun c th chuyn t dng STL sang LAD

6.3.2 Dng khi chc nng: FBD (Function Block Diagram)

Dng son tho FBD hin th chng trnh dng ha tng t nh s cc cng logic. FBD khng s dng khi nim ng ngun cung cp tri v phi; do khi nim dng in khng c s dng. Thay vo l logic 1. Khng c tip im v cun dy nh dng LAD, nhng c cc cng logic v cc hp chc nng. Cc cng logic nh AND, OR, XORs tng ng vi cc tip im logic ni tip hay song song

V d:

u ra ca cc cng logic hay hp chc nng c th c s dng ni tip vi u vo ca cc cng logic hay cc hp chc nng khc. Vi dng son tho ny c mt s im chnh sau:

Biu din dng ha cc cng chc nng gip chng ta d c hiu theo trnh t iu khin. Lun c th chuyn t hin th dng FBD sang STL. 6.3.3 Dng lit k lnh: STL (StaTement List)

y l dng son tho chng trnh dng tp hp cc cu lnh. Ngi dng phi nhp cc cu lnh t bn phm, gia lnh v ton hng (ton hng c th l a ch, d liu) c khong trng v mi lnh chim mt hng. dng son tho ny s c mt s chc nng m dng son tho LAD hay FBD khng c.

V d:

Dng san tho ny c mt s im chnh:

L dng san tho ph hp cho nhng ngi c kinh nghim lp trnh PLC.

STL cho php gii quyt mt s vn m i khi kh khn khi dng LAD hoc FBD.

Lun lun c th chuyn t dng LAD hay FBD v dng STL nhng khi chuyn ngc li t STL sang LAD hay FBD s c mt s phn t chng trnh khng chuyn c.

6.4 Son tho chng trnh vi phn mm STEP7-Micro/Win V4.0 SP6

6.4.1 M mn hnh son tho chng trnh

m STEP 7--Micro/WIN, nhp p chut vo biu tng STEP 7-Micro/WIN trn mn hnh desktop, hoc chn Start > SIMATIC > STEP 7 MicroWIN V4.0. Giao din mn hnh c dng (hnh 6.1).6.4.1.1 Vng son tho chng trnh

Vng son tho chng trnh cha chng trnh v bng khai bo bin cc b ca khi chng trnh ang c m. Chng trnh con (vit tt l SUB) v chng trnh ngt (vit tt l INT) xut hin cui ca s son tho chng trnh. Ty thuc vo vic nhp chut mc no m ca s mn hnh son tho chng trnh tng ng s c m.

6.4.1.2 Cy lnh

Cy lnh hin th tt c cc i tng ca d n v cc lnh vit chng trnh iu khin. C th s dng phng php drag and drop (ko v th) tng lnh ring t ca s cy lnh vo chng trnh, hay nhp p chut vo mt lnh m mun chn n vo v tr con tr mn hnh son tho chng trnh.

Hnh 6.1: Mn hnh son tho chng trnh STEP 7-Micro/Win

6.4.1.3 Thanh chc nng

Thanh chc nng cha mt hm cc biu tng truy cp cc c im chng trnh khc nhau ca STEP 7--Micro/WIN.

Program Block: Nhp p chut vo biu tng ny m ra ca s son tho cc chng trnh ng dng (OB1, SUB hoc INT)

Symbol Table: Bng k hiu (Symbol table) cho php ngi dng m t cc a ch s dng trong chng trnh di dng cc tn gi gi nh. iu ny gip cho vic c hiu chng trnh d dng v khi vit chng trnh t b sai st do sdng trng a ch.

Status Chart: Bng trng thi (Status chart) cho php ngi dng gim st trng thi cc ng vo v thay i trng thi tng ng ra. S dng bng trng thi kim tra ni dy phn cng v xem ni dung cc vng nh.

Trong :

Ct Address: Cho php nhp a ch cc bin hay vng nh

Ct Format: Cho php chn dng d liu ca a ch

Ct Current Value: Hin th gi tr hin hnh ca a ch

Ct New Value: Cho php thay i trng thi ng ra hay ni dung vng nh

Data Block: S dng Data Block nh mt vng nh t trc d liu cho cc bin thuc vng nh V. C th to ra cc Data block khc nhau v t tn theo d lliu chng trinh. V d:

Ca s son tho d liu:

y l khi chc nng h thng, khi m System Block chng ta c th ci t cc chc nng nh:

Communication ports: Chn cc thng s truyn thng vi thit b khc nh my tnh hay CPU khc.

Retentive Ranges: Chn cc vng nh v a ch s c thuc tnh retentive

Output Tables: Cho php thit lp cu hnh trng thi ON v OFF ca mi ng ra s khi CPU chuyn t trng thi Run sang Stop. Input filter:Cho php chn thi gian tr cho mt vi ng vo hoc tt c ng vo s (t 0.2ms n 12.8 ms). Mc ch l gip chng nhiu vic ni dy ng vo.

Pulse Catch Bits: Cho php thit lp mt ng vo bt ly s chuyn i trng thi tn hiu rt nhanh. Ngay khi c chuyn i, gi tr ng vo s c cht cho n khi c c bi chu k qut ca PLC.

Background Time: Cho php thit lp lng thi gian PLC s dnh cho cc hot ng nn trong ch RUN. c im ny c s dng ch yu iu khin nh hng ca chu k qut khi x l trng thi v trong hot ng son tho runtime.

EM Confuguration:Cc module intelligent v a ch cu hnh tng ng c nh ngha trong d n. Thng th STEP 7-Micro/WIN wizard t cc a ch ny. Configure LED: LED SF/DIAG (System Fault/Diagnostic) c th c chn sng khi thc hin chc nng cng bc (Force) hoc xy ra li vo/ra (I/O).

Increase Memory: Tng b nh chng trnh bng cch khng cho son tho ch RUN. i vi b nh D liu th khng th.

Password: Cho php t mt khu bo v chng trnh. C 4 cp ngi dng ty chn theo bng sau:M t chc nngLevel 1Level 2Level 3Level 4

c v ghi d liuCho php truy cpCho php truy cpCho php truy cpCho php truy cp

Start, Stop, khi ng CPU

c v ghi ng h thi gian (Time-off-delay clock)

Upload chng trnh, d liu, cu hnh CPUKhng bao gi cho php

Download chng trnh, data block hoc system blockYu cu PasswordYu cu PasswordYu cu Password (khng bao gi cho php vi system block)

Son tho RuntineKhng bao gi cho php

Xa chng trnh, data block hoc system block.Yu cu Password (khng bao gi cho php vi system block)

Copy chng trnh, data block hoc system block vo card nhYu cu Password

Cng bc d liu trong status chart

Ghi ng ra trng thi stop

Xa tc qut trong PLC information

So snh d nKhng bao gi cho php

Cross Reference: Bng tham chiu cho bit nhng a ch vng nh no (Byte, bit, word hay DWord, timer, counter) s dng v v tr (location) trong chng trnh cng nh chc nng ca chng.

Mt v d bng cross reference c cho hnh 6.2. Ti ct Element, nhp p vo a ch no th trnh son tho s m cho chng ta ca s chng trnh c cha a ch tng ng. Vic ny gip cho chng ta d dng kim tra hay thay i a ch khi c nhu cu.

Hnh 6.2: V d bng Cross Reference Communication v Set PG/PC Cc biu tng ny khi kch hot s m ra hp thoi cho php chng ta ci t cc giao tip vi my tnh nh: chn cng giao tip, a ch CPU, tc truyn. y l bc cn thc hin khi bt u giao tip gia PLC vi my tnh.

Hnh 6.3: Ca s Communication

Hnh 6.4: Ca s Set PG/PC Interface.

6.4.2 Thanh cng c (Toolbar) trong STEP7-Micro/WIN

Trong phn mm c t sn nhiu cng c gip ngi lp trnh d dng trong vic s dng. Cc cng c c ngha nh sau:

New Project (File menu): Khi ng mt d n mi

Open Project (File menu): M mt d n tn ti

Save Project (File menu): Lu d n

Print (File menu): In chng trnh v ti liu d n

Print Preview (File menu): Xem trc khi in

Cut (Edit menu): Ct phn chn v a vo clipboard

Copy (Edit menu): Copy phn c chn vo clipboard

Paste (Edit menu): Dn ni dung clipboard vo ca s c kch hot

Undo (Edit menu): Khi phc li phn b xa trc

Compile (PLC menu): Bin dch ca s c kch hot (Program Block hoc Data Block)

Compile All (PLC menu): Bin dch tt c cc phn t d n (Program Block, Data Block, and System Block)

Upload (File menu): Ly (Upload) cc phn t d n t PLC vo mn hnh son tho chng trnh

Download (File menu): Np (download) cc phn t d n t STEP7-MicroWin vo PLC

Option (Tools menu): Truy cp menu Options

RUN (PLC menu): t PLC ch RUN

STOP (PLC menu): t PLC ch STOP

Program Status (Debug menu): ON/OFF trng thi chng trnh trong PLC

Pause Program Status (Debug menu): Dng ON/OFF trng thi chng trnh trong PLC

Chart Status (Debug menu): ON/OFF hin th trng thi d liu trong bng Status chart

Trend View (View menu): ON/OFF xem trng thi d liu trong PLC dng th

Pause Trend View: Dng vic v th d liu

Single Read (Debug menu): S dng Single Read cp nht mt ln tt c cc gi tr trong bng Status Chart

Write All (Debug menu): Ghi tt c cc gi tr ct New Value trong bng Status Chart vo PLC

Force (Debug menu): Cng bc d liu PLC

Unforce For (Debug menu): G b cng bc d liu PLC

Unforce All (Debug menu): G b tt c cc cng bc trong bng Status Chart

Read All Forced (Debug menu): c tt c cc gi tr cng bc trong Status Chart

6.4.3. To d n STEP 7 Micro/Win6.4.3.1 To d n mi

to mt d n mi trong STEP 7 Micro/Win, chn biu menu File New hoc biu tng trong Toolbar m hp thoi New cho php to mi mt d n (project).

Trong thanh chc nng, bm vo biu tng hoc vo menu View Component Program Editor m mn hnh son tho chng trnh (hnh 6.5).

Hnh 6.5: ng dn vo mn hnh son tho chng trnhCng trong menu View, ta c th chn ngn ng lp trnh l STL, Ladder hay FBD theo mong mun. son tho bng k hiu cho cc a ch ta bm vo biu tng trong thanh chc nng, hoc vo menu View Component Symbol Table. Sau c th t k hiu cho cc a ch nh trnh by mc 6.4.1.3. Phn chi tit s c trnh by trong chng php ton nh phn. 6.4.3.2 Lu d n

lu d n, nhp chut vo biu tng , hoc vo menu File Save. Ca s mn hnh xut hin nh hnh 6.6. Chn th mc cn cha d n, t tn d n v nhp chut vo th Save lu d n

Hnh 6.6: Ca s mn hnh lu d n6.4.3.3 M mt d n

m mt d n ang c sn, nhp chut vo biu tng , hoc vo menu File Open. Ca s mn hnh xut hin nh hnh 6.7. Chn th mc cha chng trnh cn m, chn tn d n v sau nhp chut vo th Open.

Hnh 6.7: Ca s mn hnh lu d n cn m6.4.4 Th vin

Th vin (Libraries) c s dng lu tr cc khi chng trnh con c truyn tham s c s dng lp trnh. Cc khi c th copy vo trong mt th vin t mt d n c sn hoc chng c th c to ra trc tip trong th vin c lp vi cc d n. Khi ci t STEP 7 Micro/WIN th cc khi cha c ci t vo trong th vin. ci t th vin chun c th download th vin S7-200 t trang www.siemens.com hoc s dng a phn mm STEP 7 Micro/WIN Add-on: STEP 7 Micro/WIN 32 Instruction Library, V1.1 (CD-ROM).

C th chn thm hoc xa b bt cc khi chng trnh trong th vin s dng File Add/Remove Libraries v sau chn th Add chn khi chng trnh th vin mong mun a vo th vin.

m th vin, vo Cy Lnh chn mc Libraries, chn cc khi chng trnh cn s dng. Vic to thm cc khi chng trnh con truyn tham s c s dng lm th vin c th c to ra t File Create Library v chn chng trnh con cn lm th vin.

6.4.5 H thng tr gip trong STEP 7 Micro/WIN

Trng hp gp kh khn trong lp trnh cng nh cn tm hiu r hn v mt thng tin no trong phn mm ta c th s dng cng c tr gip. C nhiu cch khc nhau m tr gip:

1. S dng menu Help Contents and Index kch hot tr gip chung.

2. S dng phm F1 tr gip theo ng cnh vi i tng c chn.

Hnh 6.8: Mn hnh tr gip

Th Content: Hin th danh sch cc ch tr gip Th Index: Cho php truy cp thng tin tr gip bng vic hin th danh sch cc thut ng theo th t alphabe.

Th Find: Cho php tm kim cc t c th v thut ng trong ch tr gip.

Khi nhp chut vo cc t c ni ln c mu xanh v gch chn (hotwords) s xut hin cc tr gip chi tit hn.

6.4.6 Xa b nh CPU

Khi xa PLC th PLC phi t ch STOP v reset PLC theo chun nh my, ngoi tr a ch PLC, tc truyn, v ng h thi gian (time-of-date clock). xa chng trnh trong PLC thc hin nh sau:

1. Chn PLC Clear... th hp thoi Clear xut hin

2. Chn tt c cc mc chp nhn bng cch nhp OK.

3. Nu c password trong b nh PLC th hp thoi yu cu password xut hin. xa password th nhp CLEARPLC vo hp thoi v tip tc hot ng xa tt c.

6.4.7 M mt d n ang tn ti sn

M mt d n tn ti (tp tin c phn m rng .mwp) hay thnh phn ca d n v bt u mt phn son tho mi bng cch s dng cc phng php sau:

1. Nhp chut vo biu tng Open Project 2. Chn menu lnh File Open.

3. n t hp phm Ctrl+O

4. M Windows Explorer v nhp p chut v tp tin c phn m rng .mwp.

5. M mt thnh phn d n bng cch nhp chut phi vo cc ghi ch trong cy lnh (Instruction Tree). Chn Open m.

m cc d n c to vi cc phin bn trc ca STEP 7 Micro/WIN hay STEP 7-Micro/DOS th nhp chut vo Open hay chn File Open v chn tp tin mong mun.Ch :

- D n to bng cc phin bn trc ca STEP 7 Micro/WIN hay STEP 7 Micro/DOS c th cha mt hay nhiu cu trc logic m STEP 7 Micro/WIN V4.0 v cao hn khng h tr. m c d n, ta phi s dng phin bn c to d n v lu li d n theo th tc sau:

1. Chuyn mn hnh son tho sang STL.

2. Tt a ch theo k hiu.

3. Lu tp tin d n.

- Chng trnh to vi STEP 7-Micro/WIN V4.0 s dng lnh AND c ng vo n FBD, v c lu xem FBD, th khng th m c vi STEP 7 Micro/WIN V4.0. m cc d n ny vi STEP 7-Micro/WIN V4.0, d n trc tin nn c chuyn sang xem STL v lu li dng ny.

- Khng th s dng lnh Open m mt d n trong PLC; Cc tp tin d n ch c th m c nu n c lu tr trn PC hoc PG (thit b lp trnh)

- Vi phn mm STEP-7 Micro/WIN mi ln m ch c mt d n. V vy mun m 2 d n ti cng mt thi im th phi chy hai ln STEP-7 Micro/WIN. Khi m hai d n, ta c th copy cc phn t chng trnh ln nhau.

6.4.8 Kt ni truyn thng S7-200 vi thit b lp trnh

kt ni truyn thng S7-200 vi thit b lp trnh th cn phi c cp kt ni. Vic kt ni truyn thng thc hin theo cc bc sau:

1. Nhp chut vo biu tng communication trong thanh chc nng hay vo View Component Communications

Hnh 6.9: Mn hnh thit lp truyn thng

2. Kim tra xem a ch ca cp PC/PPI trong hp thoi c c t l 0 cha? Thng mc nh l 0.

3. Kim tra tham s mng (Network Parameters) v tc truyn (Transmission Rate) c ng cha. Nu cha ng th nhp chut vo th thit lp li giao tip gia PC v PLC.

4. Nhp p chut vo biu tng tm trm S7-200 v mt biu tng CPU cho trm S7-200 c kt ni s c hin th (v d biu tng ).5. Chn S7-200 v nhp OK. Nu STEP 7--Micro/WIN khng tm ra CPU S7 200, kim tra vic t chnh cc tham s truyn thng v lp li bc ny.

6. Sau khi thit lp truyn thng vi S7-200, ta c th sn sng to v download chng trnh vo CPU.

6.4.9 Ti d n t PLC

C th s dng biu tng trn toolbar hoc menu File ti (upload) chng trnh t PLC v my tnh khi s dng phn mm STEP 7-Micro/WIN. Cn lu l PLC c kt ni truyn thng vi thit b lp trnh. 6.4.9.1 Ti mt khi hoc ba khi

C th ti khi chng trnh (OB1, chng trnh con, chng trnh ngt), System Block, v Data Block hay chn la mt trong ba khi ny t PLC v my tnh. Chng trnh trong PLC khng cha cc a ch k hiu hay thng tin status chart. Do , ta khng th ti mt bng Symbol Table hay Status Chart. 6.4.9.2 Ti vo mt d n mi hoc d n rng

ti chng trnh v my tnh th mt cch khng lm nh hng n cc chng trnh ang m l ng n li v to mt d n mi, v d n mi l rng nn khng th v tnh ph hy d liu. y l cch thc an ton ly khi chng trnh, system block hoc thng tin data block. Nu mun ly s dng bng k hiu (symbol table) hoc status chart c to cho d n ny, th c th m d n c mn hnh STEP 7-Micro/WIN khc v copy cc thng tin ny vo d n c upload v.

6.4.9.3 Ti vo mt d n tn ti

y l mt cch vit tt c cc phn ca chng trnh hin hnh bng chng trnh c np vo PLC trc .

6.4.9.4 Th tc ti d n t PLC v thit b lp trnh

thc hin ti, thc hin cc bc sau:

1. Trong STEP 7 Micro/WIN m mt d n gi cc khi s c upload t PLC.

Nu mun upload vo mt d n rng, chn File New hoc s dng biu tng New Project trn toolbar.

Nu mun upload vo mt d n tn ti, chn File Open hoc s dng biu tng Open Project trn toolbar.

2. Chn File > Upload hoc s dng biu tng Upload trn toolbar khi ng qu trnh upload. 3. Hp thoi Upload xut hin yu cu chn cc khi: program block, data block, and system block. Hy chn cc khi mun Upload, v sau nhp OK.

Hnh 6.10: Hp thoi Upload4. STEP 7-Micro/WIN hin th ch sau:

Hnh 6.11: Ch khi upload t PLC v thit b lp trnh

Nhn Yes chp nhn vic upload.

STEP 7-Micro/WIN hin th mt thng bo khi upload cc khi thnh cng t PLC v thit b lp trnh hoc my tnh PC.

6.4.10 Np (download) mt d n vo PLC

Khi cho php kt ni truyn thng gia PC v PLC, ta c th download chng trnh vo PLC. Cn lu rng khi download mt program block, data block hay system block vo PLC th ni dung ca cc khi c download vo s vit ln cc khi hin hnh trong PLC. Cc bc thc hin nh sau:

1. Trc khi download vo PLC, cn phi kim tra xem PLC ch Stop cha thng qua n bo STOP trn PLC. Nu cng tc chn ch trn PLC t v tr TERM th ta c th chn PLC ch RUN hoc STOP t my lp trnh. Nu PLC khng ch STOP, th nhp chut vo biu tng STOP trong toolbar hoc chn PLC STOP. Trong trng hp khng dng phn mm th chuyn cng tc chn ch cho PLC v v tr STOP.

2. Nhp chut vo biu tng download trong toolbar hoc chn File Download. Hp Download xut hin.

3. Chn cc khi cn download. Thng thng l chn tt c.

4. Nhp OK bt u qu trnh download.

5. Nu download thnh cng, th mt hp thoi hin th thng bo: Download Successful. Tip tc n bc 12.

6. Nu loi PLC c chn cho chng trnh trong STEP 7/Micro/WIN khng ph hp vi PLC thc t, th mt hp thoi xut hin vi thng bo: "The PLC type selected for the project does not match the remote PLC type. Continue Download?".

7. t li loi PLC cho ph hp, chn No dng tin trnh downoad.

8. Chn PLC Type vo hp thoi chn loi PLC.

9. C th chn ng loi PLC theo danh sch trong mc ca hp thoi. Hoc nhp chut vo th STEP 7-Micro/WIN t ng tm ng loi PLC ang kt ni.

10. Nhp OK chp nhn loi PLC v ng hp thoi.

11. Khi ng li qu trnh download bng cch nhp chut vo biu tng download trong toolbar hay chn File Download.

12. Ngay khi download thnh cng, ta phi chuyn PLC t STOP sang RUN trc khi PLC c th thc hin chng trnh. Nhp chut vo biu tng RUN trong toolbar hay chn PLC RUN chuyn PLC sang ch RUN khi cng tc chn ch cho PLC v tr TERM. Trng hp s dng cng tc th chuyn t v tr STOP sang RUN.6.4.11 Thit lp cu hnh chung cho phn mm (menu option v customize)

6.4.11.1 Menu Option

C th nh ngha mt ng dn mc nh n mt th mc tp tin xc nh m v lu cc d n STEP 7-Micro/WIN. Ta s dng menu lnh Tools Options.

Ngoi ra, truy cp trc tip Option cho tng thnh phn trong cy lnh (Instruction tree) th tr chut vo thnh phn mong mun v nhp chut phi, sau chn mc option.

Hnh 6.12: Ca s Options

General Options

- Th General: Chn th ny la chn Program Editor, Mnemonic Set, Programming Mode, Language, v Regional Settings(Measurement System, Time Format, and Date Format) mc nh.

- Th Defaults: Chn th ny t v tr tp tin v loi PLC mc nh cho cc d n mi. Ta cng c th chn thm System Symbol Table cho tt c cc d n mi.

- Th Colors: Chn th ny gn Font v Color cho cc ca s khc nhau.

Program Editor Options

- Th Program Editor: Chn th ny nh kch thc, hin th v font ca ca s son tho chng trnh. Chn trng thi hin th bn trong hay bn ngoi lnh. Cu hnh a ch theo k hiu. Ta cng c th chn cho php son tho ton t sau khi t mt lnh v nh dng t ng bt k m lnh STL c nhp vo.

- Th STL Status: Chn th ny ty bin cch thc m Program Status c trnh din STL. Ta c th thay i cc t chnh sau: Watch Values, Operands, Logic Stack, Instruction Status Bits. Other Options

- Th Symbol Table: Chn th ny thit lp kiu font, kiu dng v kch thc ca bng k hiu (symbol table). Ta c th chn hin th cc k hiu trng nhau, khng c s dng.

- Th Status Chart: Chn th ny thit lp kiu font, kiu dng v kch thc ca status chart. Cng c th thit lp vic nh a ch theo k hiu.

- Th Data Block: Chn th ny thit lp kiu font, kiu dng v kch thc v rng ca data block.

- Th Cross Reference: Chn th ny thit lp kiu font, kiu dng v kch thc ca bng cross reference. Cng c th thit lp vic nh a ch theo k hiu.

- Th Output Window: Chn th ny thit lp kiu font, kiu dng v kch thc ca output window.

- Th Instruction Tree: Chn th ny thit lp kiu font, kiu dng v kch thc ca Instruction Tree (cy lnh). Ta cng c th chn cho php t ng xp li ca instruction tree.

- Th Navigation Bar: Chn th ny thit lp kiu font, kiu dng v kch thc ca navigation bar.

- Th Print: Chn th ny thit lp kiu font, kiu dng v kch thc ca cc d n mun in. 6.4.11.2 Menu Custommize

Menu custommize cho php ta thay i s xut hin ni dung trong toolbar v thm vo cc cng c c s dng thng xuyn vo menu Tools.

Hnh 6.13: Ca s custommize.

Chn menu lnh Tools Customize thit lp cc la chn sau:

- Th Commands: Cho php thay i s xut hin cc ni dung ca toolbars.

- Th Add-On Tools: Cho php thm vo cc cng c c s dng thng xuyn vo menu Tools. Thay i s xut hin:

- Chn Show Tooltips nu mun cc nt nhn hin th cc thng tin v n khi con tr chut dng trn nt nhn.

- Chn Show Flat Buttons nu mun cc nt nhn xut hin dng phng thay v xut hin dng 3-D. Di chuyn mt nt nhn:

- Chn mt toolbar t hp danh sch Category hin th cc nt nhn ca toolbar . di chuyn mt nt nhn t toolbar mc nh sang toolbar khc, th chn tn ca toolbar cha nt nhn cn di chuyn t hp danh sch Category. Ko nt nt nhn mong mun trong vng nt nhn ra vng toolbar thm n vo toolbar.

- loi b mt nt nhn trn toolbar, ko nt nhn trn toolbar v b vo vng nt nhn ca hp thoi Customize. Th Add-On Tools: Thm mt cng c vo menu Tools.

c im ny c d nh tit kim thi gian i vi cc cng c c s dng thng xuyn. thm mt cng c, nhp vo th Add-On Tools, nhp vo nt , v in vo cc vng di:Bt k lnh c yu cu c bt u v kt thc bi du ngoc kp khi nhp vo vng command (v d: "xxx xxx").

- Menu Text: Chn mt tn nhn dng cng c trn menu Tools.

- Command: Cung cp tn tp tin ca chng trnh cng c hay bat. file.

- Arguments: Cung cp cc ch dng lnh s dng bi tp tin *.exe.

- Initial Directory: Cung cp ng dn th mc ang m cho cng c. S dng nt tm cc tp tin v th mc.Khi thm vo mt cng c thnh cng, trong menu Tools xut hin cng c thm.6.4.12 Son tho chng trnh

Trc khi son tho chng trnh, cc bc sau y cn phi hon thnh:

-Kt ni gia PLC v my tnh

-Kt ni dy ng cc ng vo v ra vi ngoi vi

Trng hp khng c PLC, th ta ch c th son tho chng trnh v lu tr li. Cn nu mun kim tra th cn phi c phn mm m phng S7-200. Cc bc son tho mt d n mi:

1. M mn hnh son tho chng trnh

2. Nhp bng k hiu

3. Nhp chng trnh

4. Lu chng trnh

5. Download chng trnh vo CPU.

6. t CPU ch RUN.

7. Tm li v chnh sa chng trnh.

hiu c phn mm STEP 7-Micro/WIN d dng, chng ta nn vit mt v d n gin c cho hnh 6.14 v bng thit lp vo/ra cho bng 6.1. Do mi bt u, ta nn vit chng trnh dng LAD, ri sau c th xem dng FBD hay STL.Bng 6.1: Bng xc nh kt ni dy vo/ra vi ngoi vi

Hnh 6.14: Son tho mt chng trnh miCc bc thc hin:

Bc 1: M mn hnh son tho chng trnh

Nhp chut vo biu tng Program Block m mn hnh son tho chng trnh (hnh 6.15). Ch ca s cy lnh (instruction tree) v vng son tho chng trnh. S dng cy lnh chn cc lnh c biu din dng LAD vo cc networks ca mn hnh son tho chng trnh bng cch ko v th cc lnh t cy lnh vo cc networks. c th nhp y cc ch thch (comment), th cn hin th cc ch thch trong mn hnh son tho chng trnh. Vo View POU Comment hin th dng ch thch tiu chng trnh v View Network comments hin th dng ch thch ca tng network.

Hnh 6.16: Mn hnh son tho chng trnh

Bc 2: Nhp bng k hiu

Nhp chut vo biu tng Symbol Table m mn hnh son tho bng k hiu (hnh 6.17).

Nhp cc thng tin (ch khng du) bng 6.1 vo bng Symbol Table. Vi:

-Ct k hiu tng ng vi ct Symbol.

-Ct a ch tng ng vi ct Address.

-Ct ch thch tng ng vi ct comment.

Hnh 6.17: Mn hnh son tho bng k hiu

Sau khi nhp xong, ta c bng k hiu nh hnh 6.18.

Hnh 6.18: Bng k hiu cc phn t trong chng trnh

Trong qu trnh lp trnh c th pht sinh thm cc a ch mi. Khi pht sinh thm a ch mi, ta nn b sung a ch vo trong bng k hiu d dng cho qu trnh tm v x l li sau ny.

Bc 3: Nhp chng trnh

Nhp chut vo biu tng Program Block m li mn hnh son tho chng trnh (hnh 6.15). Nhp Network 1: Dong co quay thuan

Khi n nt nhn S_Right (I0.0), th tip im I0.0 ng, nt nhn S_Stop l thng ng nn ng vo I0.2 lun lun c in hay tip im I0.2 cng ng, v bnh thng ng ra Q0.1 cng khng c in (0) nn tip im ny cng ng. Kt hp 3 tip im ny s c dng in cung cp cho cun dy Q0.0 (ni vi K1). Contactor K1 c in ng tip im ng lc ca n cp ngun cho ng c quay thun. Tip im Q0.0 (song song I0.0) ng duy tr dng cung cp cho Q0.0 khi nt nhn S_Right h ra.

Nhp cc dng ch thch nh cho trong hnh 6.14. Nhp cc tip im nh sau:

1. Nhp p chut vo hnh tng Bit Logic hoc nhp chut vo du cng (+) ca s cy lnh hin th cc lnh trong bit logic. 2. Chn tip im Normally Open .3. Gi chut tri v ko tip im vo network u tin.

4. Nhp chut vo ??? trn tip im v nhp vo a ch: I0.0 v sau nhn phm Enter.

5. Chn tip im Normally Closed v nhp a ch I0.2

6. Chn tip im Normally Closed v sau nhp vo a ch Q0.1

7. Chn cun dy Output v nhp vo ??? a ch Q0.0

Ch : khi g cc a ch I0.0, I0.2, Q0.0, Q0.1 c th ta s nhn c kt qu l cc a ch theo k hiu. hin li cc a ch tuyt i ta b kch hot View Symbolic Addressing.

R nhnh Network 1.

1. Tng t chn tip im Normally Open gi chut tri v ko tip im vo v tr con tr chut (hnh 6.18) v t tn Q0.0.

Hnh 6.18: R nhnh network

2. con tr chut v tr nh hnh 6.19a v nhp chut vo biu tng line up kt thc (hnh 6.19b).

Hnh 6.19: R nhnh network

Nhp network 2: Dong co quay trai

Tng t nh network 1. Bc 4: Lu chng trnh

Sau khi nhp hai network lnh, ta nhp xong chng trnh. Khi lu chng trnh, ta to mt d n bao gm loi CPU S7-200 v cc tham s khc. lu mt d n, thc hin nh sau:

1. Chn File Save As

2. Nhp vo tn ca d n trong hp thoi Save As

3. Nhp OK lu d n. Bc 5: Download chng trnh vo CPU

Sau khi lu d n, ta c th download chng trnh vo S7-200.

Mi d n c lin kt vi mt loi CPU (CPU 221, CPU 222, CPU 224, CPU 224XP, hoc CPU 226). Nu kiu d n khng ph hp vi CPU ang kt ni, th STEP 7--Micro/WIN bo li khng tng thch v cc ng dn ta tip tc cng vic. Nu iu ny xy ra, chn Continue Download.

Thc hin download chng trnh nh sau:

1. Nhp chut vo biu tng Download trn toolbar hoc chn File Download download chng trnh. 2. Nhp OK download cc phn t chng trnh vo S7-200. Nu S7-200 ch RUN, mt hp thoi xut hin yu cu bn t S7-200 ch STOP. Nhp chut vo Yes t S7-200 ch STOP. Bc 6: t S7-200 ch RUN

i vi phn mm STEP 7-Micro/WIN t CPU S7-200 vo ch RUN, th cng tc chn ch ca S7-200 phi c t v tr TERM hoc RUN. Khi t S7-200 ch RUN, th S7-200 thc hin chng trnh:

1. Nhp chut vo biu tng RUN trn toolbar hoc chn PLC > RUN.

2. Nhp OK chuyn ch hot ng ca S7-200.

3. Khi S7-200 i vo ch RUN th n RUN trn PLC sng. Bc 7: Tm li v chnh sa chng trnh

Sau khi CPU ch RUN, ta c th kim tra li chng trnh bng cch n cc nt nhn S_Right, S_Stop, S_Left v quan st cc n LED Q0.0 v Q0.1. Nu n nt nhn S_Right, th n LED Q0.0 sng. n nt S_Stop, th n LED Q0.0 tt.

n nt S_Left, th n Q0.1 sng.

n nt S_Stop, th n LED Q0.1 tt.

Nu vic kim tra khng t c kt qu nh m t, th c th gim st chng trnh bng cch chn Debug Program Status hoc nhp chut vo biu tng . Da vo trng thi ca cc tip im v cc cun dy trong chng trnh m c th tm ra cc li v chnh sa cho ph hp vi yu cu cng ngh. dng chng trnh, t S7-200 v ch STOP bng cch nhp chut vo biu tng STOP hoc chn PLC STOP.

7. Cc php ton logic 7.1. Ngn xp (Logic stack)PLC S7-200 s dng mt ngn xp gm 9 bit, chng c s dng cho cc cu lnh m d liu l dng bit. Khi vit chng trnh bng ngn ng STL th lp trnh vin cn hiu r v phng thc hot ng ca cc bit trong ngn xp. Cc thut ton lin quan n ngn xp ch lm vic vi bit u v bit th hai ca ngn xp. Khi thc hin php ton kt hp hai bit u tin ca ngn xp th ngn xp c ko ln mt bit. Cu trc ca ngn xp c biu din di y:S0Stack 0 Bit u tin hay bit trn cng ca ngn xp

S1Stack 0 Bit th hai ca ngn xp

S2Stack 0 Bit th ba ca ngn xp

S3Stack 0 Bit th t ca ngn xp

S4Stack 0 Bit th nm ca ngn xp

S5Stack 0 Bit th su ca ngn xp

S6Stack 0 Bit th by ca ngn xp

S7Stack 0 Bit th tm ca ngn xp

S8Stack 0 Bit th chn ca ngn xp

Trong 9 ngn xp, Stack 0 l ngn xp quan trng nht. Gi tr logic ca Stack 0 s l kt qu ca php ton logic. Hay ni khc i, sau mt php ton logic nh phn th kt qu ca php ton s c lu Stack 0. Nu gi tr logic Stack 0 c gi tr l 0 th kt qu thu c l 0, tng t nu c gi tr l 1 th kt qu thu c l 1.

Ngoi ra, gi tr logic 1 ca Stack 0 cn l iu kin bt buc cho vic thi hnh i vi mt s lnh.

7.2. Cc lnh logic c bnMt vn quan trng i vi ngi mi lm quen vi chng trnh PLC vit di dng ngn ng LAD l vic xc nh ng trng thi cc loi tip im, c bit l cc tip im ng vo.Cc cm bin, cng tc hoc nt n thng c hai dng l thng ng (NC-Normal Closed) hoc thng m (NO-Normal Opened). V cc ng vo s c ni vi cc i tng ny nn cc tip im trong chng trnh, ty theo trng hp cng s c dng tng ng.Tip im thng m Tip im thng m s ng li khi gi tr ca bit c a ch l ??? bng 1.

Tip im thng ng Tip im thng ng s m ra khi gi tr ca bit c a ch ??? bng 0.

Ngn ngK hiu

LAD

FBD

STL

c th hiu r bn cht ca tip im thng m v tip im thng ng chng ta hy quan st hnh nh sau v a ra cu tr li cho cu hi.

(a). iu g xy ra i vi bng n H1, H2 khi cha tc ng n nt n NO v NC?

(b). iu gi xy ra i vi bng n H1 khi n nt NO?

(c). iu g xy ra i vi bng n H2 khi n nt NC?

1. Lnh lin kt logic

1.1. Lnh vo/ra

Lnh LOAD (LD):

Lnh LD np gi tr logic ca mt tip im vo trong bit u tin ca ngn xp, cc gi tr cn li ca ngn xp b y li xung mt bit.

Ton hng: I, Q, M, SM, V, C, T.

Lnh LOAD NOT (LDN):

Lnh LDN np gi tr logic ca mt tip im vo trong bit u tin ca ngn xp, cc gi tr cn li trong ngn xp b y li xung mt bit.

Ton hng: I, Q, M, SM, V,C,T.

Lnh OUTPUT (=):

Lnh sao chp ni dung ca bit u tin trong ngn xp vo bit c ch nh trong lnh. Ni dung ngn xp khng b thay i.

Ton hng bao gm: I, Q, M, SM, T, C (bit).

Lnh nhn bit cnh ln (EU) s t gi tr logic 1 vo bit u tin ca ngn xp trong mt chu k qut chng trnh khi pht hin s chuyn trng thi t 0 ln 1 ca tn hiu u vo.Lnh nhn bit cnh xung (ED) s t gi tr logic 1 vo bit u tin ca ngn xp trong mt chu k qut ca chng trnh khi pht hin s chuyn trng thi t 1 xung 0 ca tn hiu u vo.

AND

AND NOT

OR

OR NOT

II. Phn thc hnh

Bi 1: Mt ng c in KB 3 pha c iu khin bng PLC S7-200 CPU224 AC/DC/RLY. Khi n nt S1 (NO-thng h) th ng c s chy v n bo H1 mu xanh sng. Khi n nt S0 (NC-thng ng) th ng c s dng, n bo H2 mu sng, S1 tt. Khi xy ra s c qu dng lm cho tip im thng ng OL ca r le nhit ngt ra th ng c dng.

(a). Lp bng k hiu vo/ra cho PLC S7-200 CPU224 AC/DC/RLY?

(b). V s kt ni u vo/ra vi PLC S7-200 CPU224 AC/DC/RLY?

(c). V s kt ni mch ng lc cho ng c in KB 3 pha?

(d). Vit chng trnh iu khin ng c in KB 3 pha theo yu cu ca bi dng phn mm Step 7 MicroWIN 4.0?

(e). Nu thay i nt n S0 t thng ng thnh thng m v tip im thng ng ca rle nhit RN thnh tip im thng m th chng trnh iu khin phi thay i nh th no?

Gii:

(a). Bng k hiu u vo/ra cho PLC S7-200 CPU224 AC/DC/RLY

(b). S ni dy PLC vi cc thit b vo/ra vi PLC S7-200 CPU224 AC/DC/RLY

(c). S kt ni mch ng lc cho ng c in KB 3