Do an Lap Trinh Plc 3846

n hc phn 1A ti PLC

N HC PHN 1A PLC S7-200

GVHD: Nguyn c Ton NHM THC HIN Phm Song Ton Nguyn Vn Thun Dng nh Th

2

Mc Lc

CHNG MT: TNG QUAN V PLC 3 1. GII THIU CHUNG V PLC................................................................... 3 2. CU TRC - NGUYN L HOT NG CA PLC ............................ 5 3. CC HOT NG X L BN TRONG PLC........................................ 9 CHNG HAI: TM HIU S LC V PCL S7-200 CA SIEMEN ...... 11 1. GII THIU PHN CNG S7-200 ......................................................... 11 2. CU TRC B NH S7-200. .................................................................. 14 CHNG BA: TM HIU TP LNH PLC S7-200 CA SIEMEN............ 16 1. CC LNH C BN................................................................................ 16 2. CC LNH NNG CAO .......................................................................... 27 CHNG BN: PHN MN LP TRNH PLC S7-200 ............................. 42 1. PHN MN CI T Step 7 Micro Win V4.0........................................ 42 2. CCH S DNG PHN MN Step 7 Micro Win...................... 46 CHNG NM: PHN MN M PHNG PLC S7-200............................ 55 1. GII THIU.............................................................................................. 55 2. TRNH T THC HIN KHI M PHNG ............................................. 55 CHNG SU: NG DNG PLC S7-200 TRONG M HNH THANG MY ............................................................................................................. 61 1. GII THIU M HNH............................................................................ 61 2. M PHNG HOT NG CA M HNH. ......................................... 62 3. QUY C CC NG RA VO KHI KT NI PLC............................ 63 4. S MCH LP TRNH TRONG STEP 7. ......................................... 63 5. CHNG TRNH LP TRNH. ............................................................... 68 TI LIU THAM KHO.............................................................................. 71



3

CHNG MT: TNG QUAN V PLC

1. GII THIU CHUNG V PLC

PLC vit tt ca Programmable Logic Controlle, l thit b iu khin lp trnh c (kh trnh) cho php thc hin linh hot cc thut ton iu khin logic thng qua mt ngn ng lp trnh. Ngi s dng c th lp trnh thc hin mt lot trnh t cc s kin. Cc s kin ny c kch hot bi tc nhn kch thch (ng vo) tc ng vo PLC hoc qua cc hot ng c tr nh thi gian nh th hay cc s kin c m. Mt khi s kin c kch hot tht s, n bt ON hay OFF thit b iu khin bn ngoi c gi l thit b vt l. Mt b iu khin lp trnh s lin tc lp trong chng trnh do ngi s dng lp ra ch tn hiu ng vo v xut tn hiu ng ra ti cc thi im lp trnh. khc phc nhng nhc im ca b iu khin dng dy ni ( b iu khin bng Relay) ngi ta ch to ra b PLC nhm tha mn cc yu cu sau : - Lp trnh d dng , ngn ng lp trnh d hc . - Gn nh, d dng bo qun , sa cha. - Dung lng b nh ln c th cha c nhng chng trnh phc tp . - Hon ton tin cy trog mi trng cng nghip . - Giao tip c vi cc thit b thng minh khc nh : my tnh, ni mng, cc m Modul m rng. - Gi c c th cnh tranh c. Cc thit k u tin l nhm thay th cho cc phn cng Relay dy ni v cc Logic thi gian .Tuy nhin, bn cnh vic i hi tng cng dung lng nh v tnh d dng cho PLC m vn bo m tc x l cng nh gi c Chnh iu ny gy ra s quan tm su sc n vic s dng PLC trong cng nghip . Cc tp lnh nhanh chng i t cc lnh logic n gin n cc lnh m , nh thi , thanh ghi dch sau l cc chc nng lm ton trn cc my ln S pht trin cc my tnh dn n cc b PLC c dung lng ln , s lng I / O nhiu hn. Trong PLC, phn cng CPU v chng trnh l n v c bn cho qu trnh iu khin hoc x l h thng. Chc nng m b iu khin cn thc hin s c xc nh bi mt chng trnh . Chng trnh ny c np sn vo b nh ca PLC, PLC s thc hin vic iu khin da vo chng trnh ny. Nh vy nu mun thay i hay m rng chc nng ca qui trnh cng ngh , ta ch cn thay i chng trnh bn trong b nh ca PLC . Vic thay i hay m rng chc nng s c thc hin mt cch d dng m khng cn mt s can thip vt l no so vi cc b dy ni hay Relay . Hin nay vi s pht trin ca ngnh cng nghip in t cho php ch to cc h vi x l lin tip, da trn c s ca b vi x l, cc b iu khin logic c kh nng lp trnh c (PLC) ra i, cho php khc phc c rt nhiu nhc im ca cc h iu khin lin kt cng trc y, vic dng PLC tr nn rt ph bin trong cng nghip t ng ho. C th lit k cc u im chnh ca vic s dng PLC gm: - Gim bt vic u ni dy khi thit k h thng, gi tr logic ca nhim v iu khin c thc hin trong chng trnh thay cho vic u ni dy.

- Tnh mm do cao trong h thng. - B nh: Cng ngt v m tc cao khi vi x l trung tm. - H iu hnh B m vo ra B nh thi B m Bit c Cng vo ra Onboard Qun l ghp ni Bus ca PLC



4

- B nh vo ra:

Hnh 1: Nguyn l chung v cu trc ca b PLC

Cng ngt v m tc cao

+ Khi vi x l

trung tm + H iu

hnh

B m vo-ra

B nh thi

B m

Bit c

Cng vo ra

Onboard

Qun l ghp ni

Bus ca PLC



5

2. CU TRC - NGUYN L HOT NG CA PLC a. Cu trc Tt c cc PLC u c thnh phn chnh l : Mt b nh chng trnh RAM bn trong ( c th m rng thm mt s b nh ngoi EPROM ). Mt b vi x l c cng giao tip dng cho vic ghp ni vi PLC . Cc Modul vo /ra. Bn cnh , mt b PLC hon chnh cn i km thm mt n v lp trnh bng tay hay bng my tnh. Hu ht cc n v lp trnh n gin u c RAM cha ng chng trnh di dng hon thin hay b sung . Nu n v lp trnh l n v xch tay, RAM thng l loi CMOS c pin d phng, ch khi no chng trnh c kim tra v sn sng s dng th n mi truyn sang b nh PLC. i vi cc PLC ln thng lp trnh trn my tnh nhm h tr cho vic vit, c v kim tra chng trnh . Cc n v lp trnh ni vi PLC qua cng RS232, RS422, RS458, i vi PLC c nh cc b phn thng c kt hp thnh mt khi. Cng c mt s hng thit k PLC thnh tng m un ngi s dng c th la chn cu hnh PLC cho ph hp m t tn km nht, ng thi p ng c yu cu ng dng. Mt b PLC c th c nhiu m un nhng thnh phn c bn nht ca phn cng trong b PLC bao gi cng c cc khi sau: Ngun cung cp

M un nhp d liu

M un xut d liu

+ -

Nh chng trnh

Hnh 2: S cu trc phn cng ca b lp trnh PLC

Da vo s khi ta thy PLC gm c 4 khi chnh l: Khi ngun, khi vi x l b nh, khi u vo, khi u ra. Thng thng cc tn hiu xut nhp u



6

dng s (1- 0), cn nu tn hiu l dng lin tc th ta cn gn cc khi xut nhp dng lin tc (Analog).

M un ngun: (Moudule) L khi chc nng dng cung cp ngun v n nh in p cho PLC hot ng. Trong cng nghip ngi ta thng dng in p 24V mt chiu. Tuy nhin cng c b PLC s dng in p 220V xoay chiu.

M un CPU (Centrol rocessor Unit module):

Bao gm b vi x l v b nh

M un nhp: (Input Module) Tn hiu vo: Cc tn hiu u vo nhn cc thng tin iu khin bn ngoi dng tn hiu Logic hoc tn hiu tng t. Cc tn hiu Lgic c th t cc nt n iu khin cc cng tc hnh trnh, tn hiu bo ng, cc tn hiu ca cc quy trnh cng ngh,Cc tn hiu tng t a vo ca PLC c th l tn hiu in p t cc cn nhit iu chnh nhit cho mt l no hoc tn hiu t my pht tc, cm bin.

M un xut (Output Module):

Trong PLC th Module xut cng ht sc quan trng khng km module nhp. N c th c 8 hoc 16 ng ra m trn mt Module xut, do vy ngi s dng c th kt ni nhiu module li vi nhau c s ng ra ph hp. i vi nhng ng dng nh th cn 16 ng ra. Nhng ng dng ln hn c th dng ti 26 hoc 256 ng ra. Cng ging nh Module nhp th cc ng ra ca Module xut l cc tip im ca rle, kh nng chu ti ln 220V/1A. Nu mun khng ch ph ti cng sut ln th thng qua cc thit b trung gian nh: CTT. Aptomat. Triac b. Nguyn l hot ng ca PLC



7

Hnh 3: Chu k thc hin vng qut ca CPU trong b PLC Trong qu trnh thc hin chng trnh CPU lun lm vic vi bng nh ra. Tip theo ca vic qut chng trnh l truyn thng ni b v t kim tra li. Vng qut c kt thc bng giai on chuyn d liu t b m o ra ngoi vi. Nhng trng hp cn thit phi cp nht module ra ngay trong qu trnh thc hin chng trnh. Cc PLC hin i s c sn cc lnh thc hin iu ny. Tp lnh ca PLC cha cc lnh ra trc tip c bit, lnh ny s tm thi dng hot ng bnh thng ca chng trnh cp nht module ra, sau s quay li thc hin chng trnh. Thi gian cn thit PLC thc hin c mt vng qut gi l thi gian vng qut (Scan time). Thi gian vng qut khng c nh, tc l khng phi vng qut no cng c thc hin trong mt khong thi gian nh nhau. C vng qut c thc hin lu, c vng qut c thc hin nhanh tu thuc vo s lnh trong chng trnh c thc hin, vo khi lng d liu c truyn thng trong vng qut . Mt vng qut chim thi gian qut ngn th chng trnh iu khin c thc hin cng nhanh. Nguyn l hot ng da trn cc b phn sau : n v x l trung tm CPU iu khin cc hot ng bn trong PLC. B x l s c v kim tra chng trnh c cha trong b nh, sau s thc hin th t tng lnh trong chng trnh , s ng hay ngt cc u ra. Cc trng thi ng ra y c pht ti cc thit b lin kt thc thi. V ton b cc hot ng thc thi u ph thuc vo chng trnh iu khin c gi trong b nh.

Chuyn d liu t u ra Q ti cng ra

Chuyn d liu t u cng vo ti u vo I

Truyn thng v kim tra b nh

Thc hin chng trnh



8

H thng bus H thng Bus l tuyn dng truyn tn hiu, h thng gm nhiu ng tn hiu song song : Address Bus : Bus a ch dng truyn a ch n cc Modul khc nhau. Data Bus : Bus dng truyn d liu. Control Bus : Bus iu khin dng truyn cc tn hiu nh th v iu khin ng b cc hot ng trong PLC . Trong PLC cc s liu c trao i gia b vi x l v cc modul vo ra thng qua Data Bus. Address Bus v Data Bus gm 8 ng, cng thi im cho php truyn 8 bit ca 1 byte mt cch ng thi hay song song. Nu mt modul u vo nhn c a ch ca n trn Address Bus , n s chuyn tt c trnh thi u vo ca n vo Data Bus. Nu mt a ch byte ca 8 u ra xut hin trn Address Bus, modul u ra tng ng s nhn c d liu t Data bus. Control Bus s chuyn cc tn hiu iu khin vo theo di chu trnh hot ng ca PLC . Cc a ch v s liu c chuyn ln cc Bus tng ng trong mt thi gian hn ch. H thng Bus s lm nhim v trao i thng tin gia CPU, b nh v I/O . Bn cch , CPU c cung cp mt xung Clock c tn s t 118 MHZ. Xung ny quyt nh tc hot ng ca PLC v cung cp cc yu t v nh thi, ng h ca h thng. B nh PLC thng yu cu b nh trong cc trng hp : Lm b nh thi cho cc knh trng thi I/O. Lm b m trng thi cc chc nng trong PLC nh nh thi, m, ghi cc Relay. Mi lnh ca chng trnh c mt v tr ring trong b nh, tt c mi v tr trong b nh u c nh s, nhng s ny chnh l a ch trong b nh . a ch ca tng nh s c tr n bi mt b m a ch bn trong b vi x l. B vi x l s gi tr trong b m ny ln mt trc khi x l lnh tip theo . Vi mt a ch mi , ni dung ca nh tng ng s xut hin u ra, qu trnh ny c gi l qu trnh c . B nh bn trong PLC c to bi cc vi mch bn dn, mi vi mch ny c kh nng cha 2000 16000 dng lnh , ty theo loi vi mch. Trong PLC cc b nh nh RAM, EPROM u c s dng . RAM (Random Access Memory ) c th np chng trnh, thay i hay xa b ni dung bt k lc no. Ni dung ca RAM s b mt nu ngun in nui b mt . trnh tnh trng ny cc PLC u c trang b mt pin kh, c kh nng cung cp nng lng d tr cho RAM t vi thng n vi nm. Trong thc t RAM c dng khi to v kim tra chng trnh. Khuynh hng hin nay dng CMOSRAM nh kh nng tiu th thp v tui th ln . EPROM (Electrically Programmable Read Only Memory) l b nh m ngi s dng bnh thng ch c th c ch khng ghi ni dung vo c . Ni dung ca EPROM khng b mt khi mt ngun , n c gn sn trong my , c nh sn xut np v cha h iu hnh sn. Nu ngi s dng khng mun m rng b nh th ch dng thm EPROM gn bn trong PLC . Trn PG (Programer) c sn ch ghi v xa EPROM.



9

Mi trng ghi d liu th ba l a cng hoc a mm, c s dng trong my lp trnh. a cng hoc a mm c dung lng ln nn thng c dng lu nhng chng trnh ln trong mt thi gian di . Kch thc b nh : Cc PLC loi nh c th cha t 300 1000 dng lnh ty vo cng ngh ch to . Cc PLC loi ln c kch thc t 1K 16K, c kh nng cha t 2000 16000 dng lnh. Ngoi ra cn cho php gn thm b nh m rng nh RAM , EPROM. Cc ng vo ra I / O Cc ng tn hiu t b cm bin c ni vo cc modul ( cc u vo ca PLC ) , cc c cu chp hnh c ni vi cc modul ra ( cc u ra ca PLC ) . Hu ht cc PLC c in p hot ng bn trong l 5V , tn hiu x l l 12/24VDC hoc 100/240VAC. Mi n v I / O c duy nht mt a ch, cc hin th trng thi ca cc knh I / O c cung cp bi cc n LED trn PLC , iu ny lm cho vic kim tra hot ng nhp xut tr nn d dng v n gin . B x l c v xc nh cc trng thi u vo (ON,OFF) thc hin vic ng hay ngt mch u ra .

3. CC HOT NG X L BN TRONG PLC a. X l chng trnh Khi mt chng trnh c np vo b nh ca PLC , cc lnh s c trong mt vng a ch ring l trong b nh . PLC c b m a ch bn trong vi x l, v vy chng trnh bn trong b nh s c b vi x l thc hin mt cch tun t tng lnh mt, t u cho n cui chng trnh . Mi ln thc hin chng trnh t u n cui c gi l mt chu k thc hin. Thi gian thc hin mt chu k ty thuc vo tc x l ca PLC v ln ca chng trnh. Mt chu l thc hin bao gm ba giai on ni tip nhau : u tin, b x l c trng thi ca tt c u vo. Phn chng trnh phc v cng vic ny c sn trong PLC v c gi l h iu hnh . Tip theo, b x l s c v x l tun t lnh mt trong chng trnh. Trong ghi c v x l cc lnh, b vi x l s c tn hiu cc u vo, thc hin cc php ton logic v kt qu sau s xc nh trng thi ca cc u ra. Cui cng, b vi x l s gn cc trng thi mi cho cc u ra ti cc modul u ra. b. X l xut nhp Gm hai phng php khc nhau dng cho vic x l I / O trong PLC : Cp nht lin tc iu nay i hi CPU qut cc lnh ng vo (m chng xut hin trong chng trnh ), khong thi gian Delay c xy dng bn trong chc chn rng ch c nhng tn hiu hp l mi c c vo trong b nh vi x l. Cc lnh ng ra c ly trc tip ti cc thit b. Theo hot ng logic ca chng trnh , khi lnh OUT c thc hin th cc ng ra ci li vo n v I / O, v th nn chng vn gi c trng thi cho ti khi ln cp nht k tip.



10

Chp nh qu trnh xut nhp Hu ht cc PLC loi ln c th c vi trm I / O, v th CPU ch c th x l mt lnh mt thi im . Trong sut qu trnh thc thi, trng thi mi ng nhp phi c xt n ring l nhm d tm cc tc ng ca n trong chng trnh. Do chng ta yu cu relay 3ms cho mi ng vo, nn tng thi gian cho h thng ly mu lin tc tr nn rt di v tng theo s ng vo. lm tng tc thc thi chng trnh, cc ng I / O c cp nht ti mt vng c bit trong chng trnh. y, vng RAM c bit ny c dng nh mt b m lu trng thi cc logic iu khin v cc n v I / O. Mi ng vo ra u c mt a ch I / O RAM ny. Sut qu trnh copy tt c cc trng thi vo trong I / O RAM. Qu trnh ny xy ra mt chu k chng trnh (t Start n End ). Thi gian cp nht tt c cc ng vo ra ph thuc vo tng s I/O c copy tiu biu l vi ms. Thi gian thc thi chng trnh ph thuc vo chiu di chng trnh iu khin tng ng mi lnh mt khong t 110 s.



11

CHNG HAI: TM HIU S LC V PCL S7-200 CA SIEMEN

1. GII THIU PHN CNG S7-200 PLC S7-200 l mt loi PLC c nh ca cng ty Siemens. Cu trc S7-200 gm 1 CPU v cc module m rng cho nhiu ng dng khc nhau.S7-200 gm nhiu loi: CPU 221, 222, 224, 226.c nhiu nht 7 module m rng khi c nhu cu: tng s ng vo/ra, ng vo/ra Analog, kt ni mng ( AS-I, Profibus ).

Hinh 4 . Hnh dng S7-200 PLC S7-200 c cc c trng v thng s k thut nh sau :



12

Cc n bo: C 3 loi n bo hot ng:

- RUN: n xanh bo hiu PLC ang hot ng - STOP :n vng bo hiu PLC - SF (stem Failure):n bo hiu PLC b s c.

C 2 loi n ch th : - Ix.x: ch trng thi logic ng vo. - Qx.x: ch trng thi logic ng ra

c im ng vo

- Mc logic 1 : 24VDC/7mA - Mc logic 0 : n 5VDC/1MA - p ng thi gian : 0.2ms



13

- Cch ly quang : 500ACV - a ch ng vo : Ix.x

c im ng ra: - in p tc ng: 24 -28VDC/2A - Ng ra Relay hoc transitor Sourcing - Chu qu dng n 7. - in tr cch ly nh nht 100 m - in tr cng tc 200 - in tr cng tc: 200 m - Thi gian chuyn mch ti a 10 ms - Khng c ch bo v ngn mch - a ch ng ra: Qx.x - Ngun cung cp - in p ngun 20-24 VDC - Dng ti a 900 mA - Thi gian duy tr khi mt ngun 10 ms - Cu ch bn trong 2A/250V - Cng tc chn mode - Khng c cch ly ngun in .

Mode cng tc chn C 3 v tr la chn cng tc

- RUN: cho php PLC thc hin chng trnh - PLC s dng chng trnh khi c s c

- TERM :cho php my lp trnh quyt nh ch hot ng PLC Cng truyn thng

- S dng cng RS485 ghp ni vi my tnh hoc thit b khc. - Tc truyn l 9600 bauds. - Cu trc cng truyn thng c m phng nh sau :



14

- Ghp ni PLC v my tnh - S dng cp PC/PPI chuyn i gia RS232 v RS485 - Chuyn i v kt ni nh hnh sau :

Hnh 5. Kt ni PLC vi my tnh

2. CU TRC B NH S7-200. B iu khin lp trnh S7-200 c chia thnh 4 vng nh. Vi 1 t c nhim v duy tr d liu trong thi gian nht nh khi mt ngun b nh S7-200 c tnh nng ng cao, c v ghi trong phm vi ton vng loi tr cc bt nh c bit SM ( Special Memory) ch c th truy nhp c.

Vng chng trnh: L vng b nh c s dng lu tr cc lnh chng trnh vng ny thuc b nh trong c v ghi c.

Vng tham s: L vng lu gi cc tham s nh: T kho, a ch trm.cng ging nh vng chng trnh thuc b nh trong c v ghi c. Vng d liu: L vng nh ng c s dng ct cc d liu ca chng trnh bao gm cc kt qu cc php tnh n c truy cp theo tng bit tng byte vng ny c chia thnh nhng vng nh vi cc cng dng khc nhau. - Vng I (Input image register): L vng nh gm 16 byte I (c/ghi): I.O - I.15



15

- Vng Q (Output image register): L vng nh gm 16 byte Q (c/ghi): Q.O- Q.15

- Vng M (Internal memory bits): l vng nh gm c 32 byte M (c/ghi): M.O -M.31 - Vng V (Variable memory): L vng nh gm c 10240 byte V (c/ghi): V.O - V.10239 - Vng SM: (Special memory): L vng nh gm: 194 byte ca CPU chia lm 2 phn: SM0 SM29 ch c v SM30 SM194 c/ghi. - SM200-SM549 c/ghi ca cc module m rng Vng i tng: L timer (nh th), counter (b m) tc cao v cc cng vo/ra tng t c t trong vng nh cui cng vng ny khng thuc kiu non volatile nhng c ghi c.

- Timer (b nh th): c/ghi T0 -T255 - Counter (b m): c/ghi C0 - C255 - B m vo analog (c): AIW0 - AIW30 - B m ra analog (ghi): AQW0 - AQW30 - Accumulator (thanh ghi): AC0 - AC3 - B m tc cao: HSC0 - HSC5 Tt c cc min ny u c th truy nhp c theo tng bit, tng byte, tng t n (word 2byte), t kp (Double word). Cu trc chng trnh:

- Chng trnh cho S7-200 phi c cu trc bao gm chng trnh chnh (main program) sau n cc chng trnh con v cc chng trnh x l ngt.

- Chng trnh chnh c kt thc bng lnh kt thc chng trnh (MEND). - Cc chng trnh x l ngt l mt b phn ca chng trnh, nu cn s dng chng trnh x l ngt phi vit sau lnh kt thc MEND. - Cc chng trnh con c nhm li thnh mt nhm ngay sau chng trnh chnh, sau n ngay cc chng trnh x l ngt bng cch vit nh vy cu trc chng trnh c r rng v thun tin hn trong vic c chng trnh c th trn ln cc chng trnh con v chng trnh x l ngt ng sau chng trnh chnh.



16

CHNG BA: TM HIU TP LNH PLC S7-200 CA SIEMEN

1. CC LNH C BN. a. 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 trong ngn xp b y li xung mt bit.

Ton hng gm: I, O, M, SM, V, C, T.

Tip im thng m s ng khi ng vo PLC c a ch l 1.

Dng LAD Dng STL

LD I0.0

= Q0.0

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.

Tip im thng ng s m khi ng vo PLC c a ch l 1

Dng LAD Dng STL

LDN I0.0

= Q0.0



17

Hnh 6. M t lnh LD v LDN Cc dng khc nhau ca lnh LD,LDN:

STL LAD M t Ton hng

LD n n Tip im thng m s ng khi n = 1

LDN n n / Tip im thng ng s m khi n = 1

n: I, Q, M, SM, (bit) T,

C

LDI n n I

Tip im thng m s ng tc thi khi n = 1

LDNI n n /I Tip im thng ng s m tc thi

khi n = 1

n:1

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.

LAD M t Ton hng n ( )

Cun dy u ra trng thi kch thch khi

c dng iu khin i qua

n: I, Q, M, SM, T, C (bit)

n ( I )

Cun dy u ra c kch thch tc thi

khi c dng iu khin i qua

n: Q (bit)

b. Cc lnh ghi/xa gi tr cho tip im:

Lnh SET ( S ) v RESET ( R )

Hai lnh ny dng ng v ngt cc im gin on c thit k. Trong



18

LAD, logic iu khin dng in ng hay ngt cc cun dy u ra. Khi dng iu

khin n cc cun dy th cc cun dy ng hoc m cc tip im. Trong STL,

lnh truyn trng thi bit u tin ca ngn xp n cc im thit k. Nu bit ny c

gi tr bng 1, cc lnh S hoc R s ng ngt tip im hoc mt dy cc tip im

(gii hn t 1 n 255). Ni dung ca ngn xp khng b thay i bi cc lnh ny.

VD: Khi tip im I0.0 ng lnh Set hoc Reset s ng (ngt) mt mng

gm n (5) tip im k t Q0.0.

M t lnh S (Set) v R (Reset) :

STL LAD M t Ton hng S S-bit n

S bit n

( S )

ng mt mng gm n cc tip

im k t a ch S-bit

R S-bit n S bit n

( R )

Ngt mt mng gm n cc tip

im k t S-bit. Nu S-bit li

ch vo Timer hoc Counter th

lnh s xo bit u ra ca

Timer/Counter .

S-bit: I, Q, M, SM, T, C,V(bit) n (byte): IB, QB, MB, SMB, VB, AC

SI S-bit n

S bit n

( SI )

ng tc thi mt mng gm n

cc tip im k t a ch S-bit

RI S-bit n S bit n

( RI )

Ngt tc thi mt mng gm n

cc tip im k t a ch S-bit

S-bit: Q (bit)

n(byte): IB, QB,

MB, SMB, VB,

AC

c. Cc lnh logic i s Boolean:

Cc lnh tip im i s Boolean cho php to lp cc mch logic (khng c

nh). Trong LAD cc lnh ny c biu din thng qua cu trc mch, mc ni tip

hay song song cc tip im thng ng hay cc tip im thng m. Trong STL

c th s dng lnh A (And) v O (Or) cho cc hm h hoc cc lnh AN (And Not),

ON (Or Not) cho cc hm kn. Gi tr ca ngn xp thay i ph thuc vo tng lnh.

AND (A)

Dng LAD Dng STL



19

LD I0.0 A I0.1 = Q0.0

AND NOT (AN) Tn hiu ra s l nghch o ca tn hiu vo.

Dng LAD Dng STL

LD I0.0 AN I0.1 = Q0.0

OR (O).

Tn hiu ra s bng 1 khi t nht c mt tn hiu vo bng 1.

Dng LAD Dng STL

LD I0.0 O I0.1 = Q0.0

OR NOT (ON)

Dng LAD Dng STL

LD I0.0 O I0.1 = Q0.0

d. Cc lnh v tip im c bit:

Tip im no tc ng cnh xung, tc ng cnh ln:



20

C th dng cc lnh tip im c bit pht hin s chuyn tip trng thi

ca xung (sn xung) v o li trng thi ca dng cung cp (gi tr nh ca ngn

xp). LAD s dng cc tip im c bit ny tc ng vo dng cung cp. Cc

tip im c bit ny khng c ton hng ring ca chng v th phi t chng pha

trc cun dy hoc hp u ra. Tip im chuyn tip dng/m (cc lnh trc v

sn sau) c nhu cu v b nh, bi vy i vi CPU 224 c th s dng nhiu nht

l 256 lnh.

Dng LAD Dng STL

I0.0 Q0.0

P

I0.0 Q0.1

N

I0.0 Q0.2

NOT

LD I0.0

EU

= Q0.0

LD I0.0

ED

= Q0.1

LD I0.0

NOT

= Q0.2

Biu thi gian

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Do an Lap Trinh Plc 3846