TS. NGUYN NH HIN, TS. NGUYN MNH TNG

IU KHIN LOGIC V PLC Sch chuyn kho dng cho o to i hc v Sau i hc

ngnh iu khin & T ng ho

NH XUT BN KHOA HC T NHIN V CNG NGH H NI - 2007

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MC LC Ni dung Trang CHNG 1 : L THUYT C S

1.1 Nhng khi nim c bn.........................................................................................3 1.2. Cc phng php biu din hm logic ..................................................................8

1.3. Cc phng php ti thiu ho hm logic ...........................................................11

1.4. Cc h mch logic ...............................................................................................15

1.5. Grafcet - m t mch trnh t trong cng nghip ...........................................17

CHNG 2: MT S NG DNG MCH LOGIC TRONG IU KHIN 2.l. Cc thit b iu khin..........................................................................................27

2.2. Cc s khng ch ng c rto lng sc........................................................28

2.3. Cc s khng ch ng c khng ng b rto dy qun..............................32

2.4. Khng ch ng c in mt chiu .....................................................................34

CHNG 3: L LUN CHUNG V IU KHIN LOGIC LP TRNH PLC 3.1. M u.................................................................................................................36

3.2. Cc thnh phn c bn ca mt b PLC..............................................................37

3.3. Cc vn v lp trnh ........................................................................................41

3.4. nh gi u nhc im ca PLC ......................................................................47

CHNG 4: B IU KHIN PLC CPM1A 4.l. Cu hnh cng.......................................................................................................49

4.2. Ghp ni ..............................................................................................................53

4.3. Ngn ng lp trnh...............................................................................................54

CHNG 5: B IU KHIN PLC - S5 5.l. Cu to ca h PLC Step5....................................................................................58

5.2. a ch v gn a ch ..........................................................................................59

5.3. Vng i tng....................................................................................................61

5.4. Cu trc ca chng trnh S5 ..............................................................................62

5.5. Bng lnh ca S5 - 95U.......................................................................................63

5.6. C php mt s lnh c bn ca S5.....................................................................64

CHNG 6: B IU KHIN PLC - S7-20 6.1. Cu hnh cng......................................................................................................74

6.2. Cu trc b nh ...................................................................................................77

6.3. Chng trnh ca S7-200.....................................................................................79

6.4. Lp trnh mt s lnh c bn ca S7-200............................................................80

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CHNG 7: B IU KHIN PLC - S7-300 7.l. Cu hnh cng.......................................................................................................83 7.2. Vng i tng....................................................................................................86 7.3. Ngn ng lp trnh...............................................................................................88 7.4. Lp trnh mt s lnh c bn ...............................................................................89

PH LC 1 CC PHN MM LP TRNH PLC 1. Tp trnh cho OMRON.............................................................................................98 2. Lp trnh cho PLC - S5...........................................................................................105 3. Lp trnh cho PLC - S7200.....................................................................................111 4. Lp trnh cho PLC - S7-300 ...................................................................................116

PH LC 2 BNG LNH CA CC PHN MM PLC 1. BNG LNH CA PLC CPM1A .........................................................................121 2. BNG LNH CA PLC - S5................................................................................125 3. BNG LNH CA PLC - S7-200 ........................................................................128 4. BNG LNH CA PLC S7-300...........................................................................135

TI LIU THAM KHO

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PHN 1 : LOGIC HAI TRNG THI V NG DNG

CHNG 1 : L THUYT C S

1.1 Nhng khi nim c bn

1. Khi nim v logic hai trng thi Trong cuc sng cc s vt v hin tng thng biu din hai trng thi i

lp, thng qua hai trng thi i lp r rt ca n con ngi nhn thc c s vt v hin tng mt cch nhanh chng bng cch phn bit hai trng thi . Chng hn nh ni nc sch v bn, gi c t v r, nc si v khng si, hc sinh hc gii v dt, kt qu tt v xu...

Trong k thut, c bit l k thut in v iu khin, thng c khi nim v hai trng thi: ng v ct nh ng in v ct in, ng my v ngng my...

Trong ton hc, lng ho hai trng thi i lp ca s vt v hin tng ngi ta dng hai gi tr: 0 v 1. Gi tr 0 hm c trng cho mt trng thi ca s vt hoc hin tng, gi tr 1 c trng cho trng thi i lp ca s vt v hin tng . Gi cc gi tr 0 hoc 1 l cc gi tr logic.

Cc nh bc hc xy dng cc c s ton hc tnh ton cc hm v cc bin ch ly hai gi tr 0 v 1 ny, hm v bin c gi l hm v bin logic, c s ton hc tnh ton hm v bin logic gi l i s logic. i s logic cng c tn l i s Boole v ly tn nh ton hc c cng u trong vic xy dng nn cng c i s ny. i s logic l cng c ton hc phn tch v tng hp cc h thng thit b v mch s. N nghin cu cc mi quan h gia cc bin s trng thi logic. Kt qu nghin cu th hin l mt hm trng thi cng ch nhn hai gi tr 0 hoc 1 . 2. Cc hm logic c bn

Mt hm y = f(x1, x2, xn) vi cc bin x1, x2, xn ch nhn hai gi tr: 0 hoc 1 v hm y cng ch nhn hai gi tr: 0 hoc 1 th gi l hm logic. Hm logic mt bin: y = f(x)

Vi bin x s nhn hai gi tr: 0 hoc 1, nn hm y c 4 kh nng hay thng gi l 4 hm yo, y1, y2, y3 cc kh nng v cc k hiu mch rle v in t ca hm mt bin nh trong bng 1.1

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Bng 1.1

Trong cc hm trn hai hm yo v y3 lun c gi tr khng i nn t c quan

tm, thng ch xt hai hm y1 v y2 Hm logic hai bin y = f (x1, x2)

Vi hai bin logic x1, x2 mi bin nhn hai gi tr 0 v 1, nh vy c 16 t hp logic to thnh 16 hm. Cc hm ny c th hin trn bng 1.2

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Bng 1.2

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Cc hm i xng nhau qua trc nm gia gia bng 1.2 l: y7 v y8, ngha l

Hm logic n bin y = f (x1, x2, xn )

Vi hm logic n bin, mi bin nhn mt trong hai gi tr 0 hoc 1 nn vi hm logic n bin c 2n t hp bin, mi t hp bin li nhn hai gi tr 0 hoc 1, do vy s hm logic tng l 22. Do , vi 1 bin c 4 kh nng to hm, vi 2 bin c 16 kh nng to hm, vi 3 bin c 256 kh nng to hm. Nh vy, khi s bin tng th s hm c kh nng to thnh rt ln.

Trong tt c cc hm c to thnh c bit ch n hai loi hm l hm tng chun v hm tch chun. Hm tng chun l hm cha tng cc tch m mi tch c tt c cc bin ca hm. Hm tch chun l hm cha tch cc tng m mi tng u

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c tt c cc bin ca hm. 3. Cc php tnh c bn

Ngi ta xy dng ba php tnh c bn gia cc bin logic l: 1. Php ph nh (o): k hiu bng du "-" pha trn k hiu ca bin. 2. Php cng (tuyn): k hiu bng du "+". (song song). 3. Php nhn (hi): k hiu bng du ".". (ni tip).

4. Tnh cht v mt s h thc c bn 4.1. Cc tnh cht

Tnh cht ca i s logic c th hin bn lut c bn l: lut hon v, lut kt hp, lut phn phi v lut nghch o.

+ Lut hon v: x1 + x2 = x2 + x1

+ Lut kt hp: x1 + x2 + x3 = (x1 + x2 ) + x3 = x1 + (x2 + x3 ) x1.x2.x3 = (x1.x2).x3 = x1.(x2.x3)

+ Lut phn phi: (x1 + x2).x3 = x1.x3 + x2.x3

x1 + x2.x3 = (x1+x2) . (x1+x3) C th minh ho kim chng tnh ng n ca lut phn phi bng cch lp

bng 1.3. Bng 1.3

x1 0 0 0 0 1 1 1 1 x2 0 0 1 1 0 0 1 1

x3 0 1 0 1 0 1 0 1 (x1+x2) . (x1 +x3) 0 0 0 1 1 1 1 1

x1 + x2.x3 0 0 0 1 1 1 1 1

Lut phn phi c th hin qua s rle hnh 1.1 :

Hnh 1.1. Th hin lut phn phi

+ Lut nghch o:

Cng minh ho tnh ng n ca lut nghch o bng cch thnh lp bng 1.4.

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Bng 1.4

Lut nghch o c th hin qua mch rle nh trn hnh 1.2:

Lut nghch o tng qut c th hin bng nh l De Morgan:

4.2. Cc h thc c bn

Mt s h thc c bn thng dng trong i s logic c cho bng 1.5. Bng 1.5

1.2. Cc phng php biu din hm logic

C th biu din hm logic theo bn cch l: biu din bng bng trng thi, biu din bng phng php hnh hc, biu din bng biu thc i s, biu din bng bng Karnaugh (ba Can).

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1. Phng php biu din bng bng trng thi phng php ny cc gi tr ca hm c trnh by trong mt bng. Nu hm

c n bin th bng c n + 1 ct (n ct cho bin v 1 ct cho hm) v 2n hng tng ng vi 2n t hp ca bin. Bng ny thng gi l bng trng thi hay bng chn l. V d: Mt hm 3 bin y = f(x1, x2, x3) vi gi tr ca hm cho trc c biu din thnh bng 1.6:

Bng 1.6 TT t hp bin x1 x2 x3 y

0 0 0 0 1 1 0 0 1 0 2 0 1 0 1 3 0 1 1 1 4 1 0 0 0 5 1 0 1 0 6 1 1 0 1 7 1 1 1 0

u im ca phng php biu din bng bng l d nhn, t nhm ln, nhc im l cng knh, c bit khi s bin ln. 2. Phng php biu din hnh hc

Vi phng php hnh hc hm n bin c biu din trong khng gian n chiu, t hp bin c biu din thnh mt im trong khng gian, phng php ny rt phc tp khi s bin ln nn thng t dng. 3. Phng php biu din bng biu thc i s

Ngi ta chng minh c rng, mt hm logic n bin bt k bao gi cng c th biu din thnh cc hm tng chun y v tch chun y .

Cch vit hm di dng tng chun y - Hm tng chun y ch quan tm n t hp bin m hm c gi tr bng 1

S ln hm bng 1 s chnh l s tch ca cc t hp bin. - Trong mi tch, cc bin c gi tr bng 1 c gi nguyn, cn cc bin c gi

tr bng 0 th c ly gi tr o; ngha l nu xi = 1 th trong biu thc tch s c vit l xi, cn nu xi =0 th trong biu thc tch c vit l xi. Cc tch ny cn gi l cc mintec v k hiu l m.

- Hm tng chun y s l tng ca cc tch . V d: Vi hm ba bin bng 1.6 trn, c hm dng tng chun y l:

Cch vit hm di dng tch chun y - Hm tch chun y ch quan tm n t hp bin m hm c gi tr bng 0

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S ln hm bng khng s chnh l s tng ca cc t hp bin. Trong mi tng cc bin c gi tr 0 c gi nguyn, cn cc bin c gi tr 1

c ly o; ngha l nu xi = 0 th trong biu thc tng s c vit l xi, cn nu xi = 1 th trong biu thc tng c vit bng xi. Cc tng c bn cn c gi tn l cc Maxtec k hiu M.

- Hm tch chun u s l tch ca cc tng . V d: Vi hm ba bin bng 1.6 trn, c hm dng tch chun y l:

4. Phng php biu din bng bng Karnaugh (ba can)

Nguyn tc xy dng bng Karnaugh l: - biu din hm logic n bin cn thnh lp mt bng c 2n , mi tng ng

vi mt t hp bin. nh s th t cc trong bng tng ng vi th t cc t hp bin.

- Cc cnh nhau hoc i xng nhau ch cho php khc nhau v gi tr ca 1 bin.

- Trong cc ghi gi tr ca hm tng ng vi gi tr t hp bin. V d l: Bng Karnaugh cho hm ba bin bng 1.6 nh bng 1.7 sau:

V d 2: Bng Karnaugh cho hm bn bin nh bng 1.8 sau:

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1.3. Cc phng php ti thiu ho hm logic

Trong qu trnh phn tch v tng hp mch logic, phi quan tm n vn ti thiu ho hm logic. Bi v, cng mt gi tr hm logic c th c nhiu hm khc nhau, nhiu cch biu din khc nhau nhng ch tn ti mt cch biu din gn nht, ti u v s bin v s s hng hay tha s c gi l dng ti thiu. Vic ti thiu ho hm logic l a chng t mt dng bt k v dng ti thiu. Ti thiu ho hm logic mang ngha kinh t v k thut ln, c bit khi tng hp cc mch logic phc tp. Khi chn c mt s ti gin s c s bin (thit b) cng nh cc kt ni (thit b) ti gin, gim c chi ph vt t cng nh gim ng k xc sut hng hc do s phn t nhiu. V d: Hai s hnh 1.3a v hnh 1.3b u c chc nng nh nhau, nhng s a s tip im cn l 3, ng thi cn thm 1 rle trung gian p, trong khi s b ch cn 2 tip im, khng cn rle trung gian.

Thc cht vic ti thiu ho hm logic l tm dng biu din i s n gin nht

ca hm v thng c hai nhm phng php l: - Phng php bin i i s. - Phng php dng thut ton.

1. Phng php ti thiu ho hm logic bng bin i i s phng php ny cn da vo cc tnh cht v cc h thc c bn ca i s

Boole thc hin ti gin cc hm logic. Nhng do tnh trc quan ca phng php nn nhiu khi kt qu a ra vn khng khng nh r c l ti thiu hay cha. Nh vy, y khng phi l phng php cht ch cho qu trnh ti thiu ho. V d: Cho hm

2. Phng php ti thiu ho hm logic dng thut ton

Phng php dng bng Karnaugh y l phng php thng dng v n gin nht, nhng ch tin hnh c vi

h c s bin n 6. phng php ny cn quan st v x l trc tip trn bng Karnaugh.

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Quy tc ca phng php l: nu c 2n c gi tr 1 nm k nhau hp thnh mt khi vung hay ch nht th c th thay 2n ny bng mt ln vi s lng bin gim i n ln. Nh vy, bn cht ca phng php l tm cc k nhau cha gi tr 1 (cc c gi tr hm khng xc nh cng gn cho gi tr 1) sao cho lp thnh hnh vung hay ch nht cng ln cng tt. Cc bin nm trong khu vc ny b loi b l cc bin c gi tr bin i, cc bin c dng l cc bin c gi tr khng bin i (ch l 0 hoc l).

Quy lc ny p dng theo th t gim dn ln cc , sao cho cui cng ton b cc cha gi tr 1 u c bao ph. Cng c th tin hnh ti thiu theo gi tr 0 ca hm nu s lng ca n t hn nhiu so vi gi tr 1, lc by gi hm l hm ph nh. V d: Ti thiu hm

+ Lp bng Karnaugh c nh bng 1.9. Bng Karnaugh c 3 bin vi 6 mintec

c gi tr 1. Bng 1.9

+Tm nhm cc (hnh ch nht) cha cc c gi tr bng 1, c hai nhm,

nhm A v nhm B. + Loi bt cc bin cc nhm: Nhm A c bin z = 1 khng i vy n c

gi li cn hai bin x v y thay i theo tng ct do vy mintec mi A ch cn bin z: A = z. Nhm B c bin x v z thay i, cn bin y khng i vy mintec mi B ch cn bin y : B = y .

Kt qu ti thiu ho l: f = a+b = z+y. Phng php Quine Mc. Cluskey

y l phng php c tnh tng qut, cho php ti thiu ho mi hm logic vi s lng bin ln. a. Mt s nh ngha

+ nh: l mt tch cha y cc bin ca hm, nu hm c n bin th nh l tch ca n bin.

nh 1 l nh m hm c gi tr bng 1 . nh 0 l nh m hm c gi tr bng 0.

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nh khng xc nh l nh m ti hm c th ly mt trong hai gi tr 0 hoc 1 .

+ Tch cc tiu: l tch c s bin l cc tiu hm c gi tr bng 1 hoc khng xc nh.

+ Tch quan trng: l tch cc tiu m gi tr hm ch duy nht bng 1 tch ny. b. Ti thiu ho bng phng php Quine Mc. Cluskey

r phng php hy xt v d minh ho, ti thiu ho hm f(x1,x2,x3,x4) Vi Cc nh bng 1 l L = 2, 3, 7, 12, 14, 15 v cc nh c gi tr hm khng xc nh l N = 6, 13. Cc bc tin hnh nh sau: Bc 1: Tm cc tch cc tiu

Lp bng biu din cc gi tr hm bng 1 v cc gi tr khng xc nh ng vi m nh phn ca cc bin theo th t s s 1 tng dn (bng 1.10a.

Xp thnh tng nhm theo s lng ch s 1 vi th t tng dn. (bng 1.10b c 4 nhm: nhm 1 c 1 s cha 1 ch s 1 ; nhm 2 gm 3 s cha 2 ch s 1 ; nhm 3 gm 3 s cha 3 ch s 1, nhm 4 c 1 s cha 4 ch s 1).

So snh mi t hp th i vi t hp th i + 1, nu hai t hp ch khc nhau mt ct th kt hp 2 t hp thnh mt t hp mi, ng thi thay ct s khc nhau ca 2 t hp c bng mt gch ngang (-) v nh du v vo hai t hp c (bng 1.10c). V c s ton hc, y thu gn cc t hp dng tnh cht:

C tip tc c ng vic, t bng 1.10c chn ra cc t hp ch khc nhau 1 ch s

1 v c cng v tr gch ngang (-) trong mt ct, ngha l c cng bin va c gin c bng 1.10c, nh vy c bng 1.10d.

Bng 1.10 a b c d

S thp phn

C s 2 x1x2x3x4

S ch s 1

S thp phn

C s 2 x1x2x3x4

Lin kt x1x2x3x4 Lin kt x1x2x3x4

2 0010 1 2 0010v 2,3 001-v 2,3,6,7 2,6,3,7 0-1-

3 0011 3 0011v 2,6 0-10v 6,7,14,15 6,14,7,15 -11-

6 * 0110 6 0110v 3,7 0-11v 12,13,14,15 11- - 12 1100

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12 1100v 6,7 011-v 7 0111 7 0111v 6,14 -110v

13 * 1101 13 1101v 12,13 110-v 14 1110

3 14 1110v 12,14 110v

15 1111 15 1111v 7,15 -111v 13,15 11-1v

4 14,15 111-v

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Qu trnh tip tc cho n khi khng cn kh nng kt hp na. Cc t hp tm c bng 1.10d l t hp cui cng, cc t hp ny khng cn kh nng kt hp na, y chnh l cc tch cc tiu ca hm cho. Theo th t x1x2x3x4, cc xk v tr c du (-) c lc b, cc xk v tr gi tr 0 c ly nghch o, cc tch cc tiu trong v d c vit nh sau:

0-1- (ph cc nh 2, 3, 6, 7) ng vi: x1x3. -11- (ph cc nh 6, 7, 14, 15) ng vi: x2x3. 1 1- - (ph cc nh 12, 13, 14, 15 ) ng vi : x1x2.

Bc 2: Tm cc tch quan trng Vic tm cc tch quan trng cng c tin hnh theo cc bc nh. Gi Li l tp cc nh 1 ang xt bc nh th i, lc ny khng quan tm n

cc nh c gi tr khng xc nh na. Zi l tp cc tch cc tiu ang bc nh th i. Ei l tp cc tch quan trng bc nh th i. Vi i = 0

Xc nh cc tch quan trng Eo t tp Lo v Zo nh sau: + Lp bng trong mi hng ng vi mt tch cc tiu thuc Zo mi ct ng

vi mt nh thuc Lo. nh du "x" vo cc trong bng ng vi tch cc tiu bng 1.11 (tch x1x3 ng vi cc nh 2, 3, 7; tch x2x3 ng vi cc nh 7, 14, 5; tch x1x2 ng vi cc nh 12, 14, 15 bng 1.10).

Bng 1.11

Xt tng ct, ct no ch c mt du "x" th tch cc tiu (hng) ng vi n l

tch quan trng, i thnh du "(x)". Vy tp cc tch quan trng bc ny l:

Vi i = 1

Tm L1 t Lo bng cch loi khi Lo cc nh 1 ca Eo Tm Z1 t Zo bng cch loi khi Zo cc tch trong Eo v cc tch nm trong

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hng c chn t Eo. Khi tm c L1, v Z1, lm li nh bc i = 0 s tm c tch quan trng E1.

Cng vic c tip tc cho n khi Lk = 0. Trong v d ny v Eo = (x1x3, x1 x2 ) m cc nh 1 ca x1x3 l 2, 3, 7; cc nh 1

ca x1, x2 l 12, 14, 15 (b qua nh 6, 13 l cc nh khng xc nh); do L1 = 0, qu trnh kt thc. Kt qu dng hm ti thiu chnh l tng ca cc tch cc tiu. Vy hm cc tiu l:

1.4. Cc h mch logic

Cc php ton v nh l ca i s Boole gip cho thao tc cc biu thc logic. Trong k thut thc t l cch ni cng logic ca cc mch logic vi nhau (theo kt cu ti gin nu c). thc hin mt bi ton iu khin phc tp, s mch logic s ph thuc vo s lng u vo v cch gii quyt bng loi mch logic no, s dng cc php ton hay nh l no. y l mt bi ton ti u nhiu khi c khng ch mt li gii. Tu theo loi mch logic m vic gii cc bi ton c nhng phng php khc nhau. V c bn cc mch logic c chia lm hai loi:

+ Mch logic t hp. + Mch logic trnh t.

1. Mch logic t hp Mch logic t hp l mch m u ra ti bt k thi im no ch ph thuc t

hp cc trng thi ca u vo thi im . Nh vy, mch khng c phn t nh. Theo quan im iu khin th mch t hp l mch h, h khng c phn hi, ngha l trng thi ng m ca cc phn t trong mch hon ton khng b nh hng bi trng thi tn hiu u ra.

S mch logic t hp nh hnh 1.4.

Hnh 1.4. Mch t hp

Vi mch logic t hp tn ti hai loi bi ton l bi ton phn tch v bi ton tng hp.

+ Bi ton phn tch c nhim v l t mch t hp c, m t hot ng v vit cc hm logic ca cc u ra theo cc bin u vo v nu cn c th xt ti vic ti thiu ho mch.

+ Bi ton tng hp thc cht l thit k mch t hp. Nhim v chnh l thit k c mch t hp tho mn yu cu k thut nhng mch phi ti gin. Bi ton tng

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hp l bi ton phc tp, v ngoi cc yu cu v chc nng logic, vic tng hp mch cn ph thuc vo vic s dng cc phn t, chng hn nh phn t l cc loi: rle - cng tc t, loi phn t kh nn hay loi phn t l bn dn, vi mch... Vi mi loi phn t logic c s dng th ngoi nguyn l chung v mch logic cn i hi phi b sung nhng nguyn tc ring lc tng hp v thit k h thng. V d: Mch logic t hp nh hnh 1.5.

2. Mch logic trnh t

Mch trnh t hay cn gi l mch dy (sequential circuits) l mch trong trng thi ca tn hiu ra khng nhng ph thuc tn hiu vo m cn ph thuc c trnh t tc ng ca tn hiu vo, ngha l mch c nh cc trng thi. Nh vy, v mt thit b th mch trnh t khng nhng ch c cc phn t ng m m cn c c cc phn t nh.

S nguyn l mch logic trnh t nh hnh 1.6. Xt mch logic trnh t nh hnh 1.7. Xt hot ng ca mch khi thay i trng

thi ng m ca x1 v x2. Biu hnh 1.7b m t hot ng ca mch, trong biu cc nt m biu hin tn hiu c gi tr 1, cn nt mnh biu hin tn hiu c gi tr 0.

Hnh 1.7. S mch trnh t

T biu hnh l.7b thy, trng thi z = 1 ch t c khi thao tc theo trnh t x1 = 1, tip theo x2 = 1. Nu cho x2 = 1 trc, sau cho x1 = 1 th c y v z u khng th bng 1 .

m t mch trnh t c th dng bng chuyn trng thi, dng hnh trng thi Mealy, hnh trng thi Moore hoc dng phng php lu . Trong phng php lu c dng trc quan hn. T lu thut ton d dng chuyn sang dng hnh trng thi Mealy hoc hnh trng thi Moore, v t c th thit k

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c mch trnh t. Vi mch logic trnh t cng c bi ton phn tch v bi ton tng hp.

1.5. Grafcet - m t mch trnh t trong cng nghip

1. Hot ng ca thit b cng nghip theo logic trnh t Trong dy chuyn sn xut cng nghip, cc thit b my mc thng hot ng

theo mt trnh t logic cht ch nhm m bo cht lng sn phm v an ton cho ngi v thit b.

Mt qu trnh cng ngh no cng c th c ba hnh thc iu khin hot ng sau:

+ iu khin hon ton t ng, lc ny ch cn s ch huy chung ca nhn vin vn hnh h thng.

+ iu khin bn t ng, qu trnh lm vic c lin quan trc tip n cc thao tc lin tc ca con ngi gia cc chui hot ng t ng.

+ iu khin bng tay, tt c hot ng ca h u do con ngi thao tc. Trong qu trnh lm vic m bo an ton, tin cy v linh hot, h iu khin

cn c s chuyn i d dng t iu khin bng tay sang t ng v ngc li, v nh vy h iu khin mi p ng ng cc yu cu thc t.

Trong qu trnh lm vic s khng bnh thng trong hot ng ca dy chuyn c rt nhiu loi, khi thit k phi c gng m t chng mt cch y nht. Trong s cc hot ng khng bnh thng ca chng trnh iu khin mt dy chuyn t ng, ngi ta thng phn bit ra cc loi sau:

+ H hng mt b phn trong cu trc iu khin, lc ny cn phi x l ring phn chng trnh c ch h hng, ng thi phi lu tm cho dy chuyn hot ng lc c h hng v sn sng chp nhn li diu khin khi h hng c sa cha xong.

+ H hng trong cu trc trnh t iu khin. + H hng b phn chp hnh (nh h hng thit b chp hnh, h hng cm

bin, h hng cc b phn thao tc...). Khi thit k h thng phi tnh n cc phng thc lm vic khc nhau m

bo an ton v x l kp thi cc h hng trong h thng, phi lun c phng n can thip trc tip ca ngi vn hnh n vic dng my khn cp, x l tc nghn vt liu v cc hin tng nguy him khc. Grafcel l cng c rt hu ch thit k v thc hin y cc yu cu ca h t ng cho cc qu trnh cng ngh k trn. 2. nh ngha Grafcet

Grafcet l t vit tt ca ting Php "Graphe fonctionnel de commande tape transition" (chui chc nng iu khin giai on - chuyn tip), do hai c quan AFCET (Lin hp Php v tin hc, kinh t v k thut) v ADEPA (t chc nh nc v pht trin nn sn xut t ng ho) hp tc son tho thng 11/1982 c ng k

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t chc tiu chun ho Php. Nh vy, mng grafcet c tiu chun ho v c cng nhn l mt ngn ng thch hp cho vic m t hot ng dy ca qu trnh t ng ho trong sn xut.

Mng grafcet l mt hnh chc nng cho php m t cc trng thi lm vic ca h thng v biu din qu trnh iu khin vi cc trng thi v s chuyn i t trng thi ny sang trng thi khc, l mt hnh nh hng c xc nh bi cc phn t l: tp cc trng thi, tp cc iu kin chuyn trng thi.

Mng grafcet m t thnh chui cc giai on trong chu trnh sn xut. Mng grafcet cho mt qu trnh sn xut lun lun l mt hnh khp kn t

trng thi u n trng thi cui v t trng thi cui v trng thi u. 3. Mt s k hiu trong grafcet

- Mt trng thi (giai on) c biu din bng mt hnh vung c nh s th t ch trng thi. Gn lin vi biu tng trng thi l mt hnh ch nht bn cnh, trong hnh ch nht ny c ghi cc tc ng ca trng thi hnh l.8a v b. Mt trng thi c th tng ng vi mt hoc nhiu hnh ng ca qu trnh sn xut

Trng thi khi ng c th hin bng 2 hnh vung lng vo nhau, th t thng l 1 hnh l.8c.

- Trng thi hot ng (tch cc) c thm du trong hnh vung trng thi hnh l.8d.

Hnh 1.8. Cc trng thi trong grafcet

- Vic chuyn tip t trng thi ny sang trng thi khc ch c th c thc hin khi cc iu kin chuyn tip c tho mn. Chng hn, vic chuyn tip gia cc trng thi 3 v 4 hnh 1.9a c thc hin khi tc ng ln bin b, cn chuyn tip gia trng thi 5 v 6 c thc hin sn tng ca bin c hnh 1.9b, hnh l.9c l tc ng sn gim ca bin d. Chuyn tip gia trng thi 9 v 10 hnh 1.9d s xy ra sau 2s k t khi c tc ng cui cng ca trng thi 9 c thc hin.

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- K hiu phn nhnh nh hnh 1.10, s phn nhnh li tn ti hai loi l s

r nhnh v s song song. S r nhnh l phn s c hai iu kin lin h gia ba trng thi nh hnh

1.1a v b . S song song l s ch c mt iu kin lin h gia 3 trng thi nh hnh

1.10c v d . hnh 1.10a, khi trng thi 1 ang hot ng, nu chuyn tip t12 tho mn th

trng thi 2 hot ng; nu chuyn tip t13 tho mn th trng thi 3 hot ng. hnh 1.10b nu trng thi 7 ang hot ng v c t79 th trng thi 9 hot ng,

nu trng thi 8 ang hot ng v c t89 th trng thi 9 hot ng. hnh 1.10c nu trng thi 1 ang hot ng v c t123 th trng thi 2 v 3 ng

thi hot ng. hnh 1.10d nu trng thi 7 v 8 ang cng hot ng v c t789 th trng thi 9

hot ng

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K hiu bc nhy nh hnh 1.11 .

Hnh 1.11. K hiu bc nhy

Hnh 1.11a biu din grafcet cho php thc hin bc nhy, khi trng thi 2 ang hot ng nu c iu kin a th qu trnh s chuyn hot ng t trng thi 2 sang trng thi 5 b qua cc trng thi trung gian 3 v 4, nu iu kin a khng c tho mn th qu trnh chuyn tip theo trnh t 2, 3, 4, 5.

Hnh 1.11b khi trng thi 8 ang hot ng nu tho mn iu kin f th qu trnh

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chuyn sang trng thi 9, nu khng tho mn iu kin 8 th qu trnh quay li trng thi 7. 4. Cch xy dng mng grafcet

xy dng mng grafcet cho mt qu trnh no th trc tin phi m t mi hnh vi t ng bao gm cc giai on v cc iu kin chuyn tip, sau la chn cc dn ng v cc cm bin ri m t chng bng cc k hiu, sau kt ni chng li theo cch m t ca grafcet. V d : kp cht chi tit c v khoan trn mt l hnh 1.12 th trc tin ngi iu khin n nt khi ng d khi ng chu trnh cng ngh t ng, qu trnh bt u t giai on 1 :

Hnh 1.12. S quy trnh khoan

+ Giai on 1: S1 Pttng A chuyn ng theo chiu A+ kp cht chi tit c. Khi lc kp t yu cu c xc nh bi cm bin p sut a1 th chuyn sang giai on 2.

+ Giai on 2: S2 u khoan B i xung theo chiu B+ v mi khoan quay theo chiu R, khi khoan su, xc nh bng nt b1 th kt thc giai on 2, chuyn sang giai on 3.

+ Giai on 3: S3 mi khoan i ln theo chiu B- v ngng quay. Khi mi khoan ln cao, xc nh bng bo th khoan dng v chuyn sang giai on 4.

+ Giai on 4: S4 Pttng A tr v theo chiu A- ni lng chi tit, v tr tr v c xc nh bi ao khi mung ngng chuyn ng, kt thc mt chu k gia cng.

S grafcet nh hnh 1.13 . 5. Phn tch mng grafcet 5.1. Quy tc vt qua, chuyn tip

- Mt trng thi trc ch chuyn tip sang trng thi sau khi n ang hot ng (tch cc) v c iu kin chuyn tip.

- Khi qu trnh chuyn tip sang trng thi sau th giai on sau hot ng (tch cc) v s kh b hot ng ca trng thi trc (giai on trc ht tch cc)

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Vi cc iu kin hot ng nh trn th c nhiu khi s khng hot ng

c hoc hot ng khng tt. Ngi ta gi: + S khng hot ng c l s c nhnh cht. (S c nhnh cht c

th vn hot ng nu nh khng i vo nhnh cht). + S khng sch l s m ti mt v tr no c pht lnh hai ln. V d 1 : S hnh 1.14 l s c nhnh cht. S ny khng th lm vic

c do S2 v S4 khng th cng tch cc v gi s h ang trng thi ban u So nu c iu kin 3 th So ht tch cc v chuyn sang S3 tch cc. Sau nu c iu kin 4 th S3 ht tch cc v S4 tch cc. Nu lc ny c iu kin 1 th S1 cng khng th tch cc c v So ht tch cc. Do khng bao gi S2 tch cc c na, m S5 tch cc th phi c S2 v S4 cng tch cc km iu kin 5 nh vy h s nm im v tr S4

Mun s trn lm vic c phi chuyn mch r nhnh thnh mch song song.

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V d 2: S hnh 1.15 l s khng sch. Gi s mng ang trng thi

ban u nu c iu kin 1 th s chuyn trng thi cho c S1 v S3 tch cc, nu c iu kin 3 ri 4 th s chuyn cho S5 tch cc, khi cha c iu kin 6 m li c iu kin 2 ri 5 trc th S5 li chuyn tch cc ln na. Tc l c hai ln lnh cho S5 tch cc, vy l s khng sch.

V d 3: S hnh 1.16 l s sch. s ny nu c S3 tch cc (diu kin 3) th nu c iu kin 1 cng khng c ngha v So ht tch cc. Nh vy, mch r sang nhnh 2, nu ln lt c cc iu kin 4 v 6 th S5 s tch cc sau nu c iu kin 7 th h li tr v trng thi ban u. 5.2. Phn tch mng grafcet

Nh phn tch trn th nhiu khi mng grafcet khng hot ng c hoc hot ng khng tt. Nhng i vi cc mng khng hot ng c hoc hot ng khng tt vn c th lm vic c nu nh khng i vo nhnh cht. Trong thc t sn xut mt h thng c th ang hot ng rt tt, nhng nu v l do no m h thng phi thay i ch lm vic (do s c tng phn hoc do thay i cng ngh...) th c th h thng s khng hot ng c nu l nhnh cht.

Vi cch phn tch s nh trn th kh nh gi c cc mng c phc - tp ln. Do , phi xt mt cch phn tch mng grafcet l dng phng php gin im.

thnh lp gin im cn i theo cc bc sau: + V mt u tin cho gin im, ghi s 0. Xut pht t giai on u trn

grafcet c coi l ang tch cc, giai on ny ang c du ".", khi c mt iu kin c thc hin, s c cc giai on mi c tch cc th:

- nh du "." vo cc giai on va c tch cc trn grafcet,

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- Xo du "." giai on ht tch cc trn grafcet, - To mt mi trn gin im sau iu kin va thc hin, - Ghi ht cc giai on tch cc ca h (c du ".") vo mi va to. + T cc thnh lp khi mt iu kin no li c thc hin th cc giai

on tch cc li c chuyn i, li lp li bn bc nh trn. + Qu trnh c nh vy tip tc, c th v hon thin c gin im (s

to thnh mch lin tc, sau khi kt thc li tr v im xut pht) hoc khng v hon thin c. Nhn vo gin im s c cc kt lun sau:

- Nu trong qu trnh v n giai on no khng th v tip c na (khng hon thin s ) th s l s c nhnh cht, v d 2.

- Nu v c ht m v tr no c cc im lm vic cng tn th l s khng sch v d 3.

- Nu v c ht v khng c v tr no c cc im lm vic cng tn th l s lm vic tt, s sch v d 1 .

V d 1 : V gin im cho s sch hnh 1.17a. thi im u h ang giai on So (c du "."), khi iu kin 1 c thc

hin th c Sl v S3 cng chuyn sang tch cc, nh du "." vo Sl v S3 xo du "." So. Vy, sau iu kin 1 to mi v trong ny cn ghi hai trng thi tch cc l 1,3. Nu cc iu kin khc khng din ra th mch vn trng thi 1 v 3.

Khi h ang 1,3 nu iu kin 4 c thc hin th giai on 4 tch cc (thm du "."), giai on 3 ht tch cc (mt du "."). Vy sau iu kin 4 to mi (ni vi 1,3), ny ghi hai trng thi tch cc cn li trn grafcet l 1, 4.

Hnh 1.17. Gin im s sch

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Khi h ang 1,3 nu iu kin 2 c thc hin th giai on 2 tch cc (thm du "."), giai on 1 ht tch cc (mt du "."). Vy sau iu kin 2 to mi (ni vi l,3), ny ghi hai trng thi tch cc cn li trn grafcet l 2,3.

Khi h ang 1,4 hoc 2,3 nu c iu kin 5 th qu trnh vn khng chuyn tip v chuyn giai on 5 phi c S2 v S4 Cng tch cc kt hp iu kin 5.

Khi h ang 1,4 nu iu kin 2 c thc hin th giai on 2 tch cc (thm du "."), giai on 1 ht tch cc (mt du "."). Vy sau iu kin 2 to mi (ni vi l,4), ny ghi hai trng thi tch cc cn li trn grafcet l 2,4.

Khi h ang 2,3 nu iu kin 4 c thc hin th giai on 4 tch cc (thm du "."), giai on 3 ht tch cc (mt du "."). Vy sau iu kin 4 to mi (ni vi 2,3), ny ghi hai trng thi tch cc cn li trn grafcet l 2,4.

Khi h ang 2,4 nu iu kin 5 c thc hin th giai on 5 tch cc (thm du "."), giai on 2 v 4 ht tch cc (mt du "."). Vy sau iu kin 5 to mi (ni vi 2,4), ny ghi trng thi tch cc cn li trn grafcet l 5.

Khi h ang 5 nu iu kin 6 c thc hin th giai on 0 tch cc (thm du "."), giai on 5 ht tch cc (mt du "."), h tr v trng thi ban u.

T gin im, thy khng c no c 2 im lm vic cng tn v v c c s , vy l s sch.

V d 2 : V gin im cho s c nhnh cht hnh 1.14 Gin im nh hnh 1.18. Trong trng hp ny khng th v tip c na

v S5 tch cc phi c c S2 v S4 cng tch cc cng iu kin 5, nhng khng c no c 2, 4. V d 3: V gin im cho s khng sch hnh 1.5.

Cch tin hnh v gin im nh trn, gin im nh hnh 1.19. T gin

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im nhn thy c nhiu c 2 im lm vic trng nhau (cng tn), vy l s khng sch. gin im hnh 1.19 c th tip tc v gin s m rng.

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CHNG 2: MT S NG DNG MCH LOGIC TRONG IU KHIN

2.l. Cc thit b iu khin

1. Cc nguyn tc iu khin Qu trnh lm vic ca ng c in truyn ng mt my sn xut thng

gm cc giai on: khi ng, lm vic v iu chnh tc , dng v c th c c giai on o chiu. Xt ng c l mt thit b ng lc, qu trnh lm vic v c bit l qu trnh khi ng, hm thng c dng in ln, t thn ng c in va l thit b chp hnh nhng cng va l i tng iu khin phc tp. V nguyn l khng ch truyn ng in, khi ng v hm ng c vi dng in c hn ch trong gii hn cho php, thng dng ba nguyn tc khng ch t ng sau:

- Nguyn tc thi gian: Vic ng ct thay i tc ng c da theo nguyn tc thi gian, ngha l sau nhng khong thi gian xc nh s c tn hiu iu khin thay i tc ng c. Phn t cm bin v khng ch c bn y l rle thi gian.

- Nguyn tc tc : Vic ng ct thay i tc ng c da vo nguyn l xc nh tc tc thi ca ng c. Phn t cm bin v khng ch c bn y l rle tc .

- Nguyn tc dng in: Bit tc ng c do m men ng c xc nh, m m men li ph thuc vo dng in chy qua ng c, do vy c th o dng in khng ch qu trnh thay i tc ng c in. Phn t cm bin v khng ch c bn y l rle dng in.

Mi nguyn tc iu khin u c u nhc im ring, ty tng trng hp c th m chn cc phng php cho ph hp. 2. Cc thit b iu khin

iu khin s lm vic ca cc thit b cn phi c cc thit b iu khin. ng ct khng thng xuyn thng dng ptmt. Trong ptmt h thng

tip im c b phn dp h quang v cc b phn t ng ct mch bo v qu ti v ngn mch. B phn ct mch in bng tc ng in t theo kiu dng in cc i. Khi dng in vt qu tr s cho php chng s ct mch in bo v ngn mch, ngoi ra cn c rle nhit bo v qu ti.

Phn t c bn ca rle nhit l bn lng kim gm hai ming kim loi c dn n nhit khc nhau dn li vi nhau. Khi bn lng kim khi b t nng (thng l bng dng in cn bo v) s b bin dng (cong), bin dng ti ngng th s tc ng vo cc b phn khc ct mch in.

Cc rle in t, cng tc t tc dng nh lc ht in t. Cu to ca rle in

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t thng gm cc b phn chnh sau: cun ht; mch t tnh lm bng vt liu st t; phn ng cn gi l phn ng v h thng cc tip im.

Mch t ca rle c dng in mt chiu chy qua lm bng thp khi, cn mch

t ca rle dng in xoay chiu lm bng l thp k thut in. chng rung v lc ht ca nam chm in c dng xung trn mt cc ngi ta t vng ngn mch. Sc in ng cm ng trong vng ngn mch s to ra dng in v lm cho t thng qua vng ngn mch lch pha vi t thng chnh, nh lc ht phn ng khng b gin on, cc tip im lun c tip xc tt.

Tu theo nguyn l tc ng ngi ta ch to nhiu loi thit b iu khin khc nhau nh rle dng in, rle in p, rle thi gian....

H thng tip im ca cc thit b iu khin c cu to khc nhau v thng m bc hay thic m bo tip xc tt. Cc thit b ng ct mch ng lc c dng in ln, h thng tip im chnh c b phn dp h quang, ngoi ra cn c cc tip im ph ng ct cho mch iu khin. Tu theo trng thi tip im ngi ta chia ra cc loi tip im khc nhau. Mt s k hiu thng gp nh bng 2.1.

2.2. Cc s khng ch ng c rto lng sc

Tu theo cng sut v yu cu cng ngh m ng c khng ng b rto lng sc c th c ni trc tip vo li in, dng i ni sao-tam gic, qua in khng, qua bin p t ngu, ngy nay thng dng cc b khi ng mm khi ng ng c. Xt mt s s n gin. 1. Mch khng ch n gin

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Vi ng c cng sut nh c th ng trc tip vo li in. Nu ng c ch quay theo mt chiu th mch ng ct c th dng cu dao, ptmt. Vi thit b ng ct ny c nhc im l khi ang lm vic nu mt in, th khi c in tr li ng c s t khi ng. trnh iu dng khi ng t n ng ct cho ng c.

Xt s ng ct c o chiu dng khi ng t kp nh hnh 2.1. Cu dao trn mch ng lc l cu dao cch ly (cu dao ny ch yu ng ct

khng ti, cch ly khi sa cha). Cc tip im T1, T2, T3 ng ng c chy thun, cc tip im N1, N2, N3

ng ng c chy ngc (o th t hai trong ba pha li in). Cc tip im T5 v N5 l cc kho lin ng v in khng ch cc ch

chy thun v ngc khng th cng ng thi, nu ang chy thun th T5 m, N khng th c in, nu ang chy ngc th N5 m, T khng th c in. Ngoi cc lin ng v in khi ng t kp cn c lin ng c kh. Khi cun T ht th ly c kh kho khng cho cun N ht na, khi cun N ht th ly c kh kho

Trong mch dng hai rle nhit RN1 v RN2 bo v qu ti cho ng c, khi

ng c qu ti th rle nhit tc ng lm cc tip im ca n bn mch iu khin m, cc cun ht mt in ct in ng c.

khi ng ng c chy thun (hoc ngc) n nt KT (hoc KN) cun ht T c in, ng cc tip im T1... T3 cp in cho ng c chy theo chiu thun, tip im T4 ng li t duy tr.

dng ng c n nt dng D, cc cun ht mt in, ct in ng c khi li in, ng c t dng.

o chiu ng c trc ht phi n nt dng D, cc cun ht mt in mi n nt o chiu. 2. Mch khng ch o chiu c gim st tc

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Xt s khng ch ng c rto lng sc quay theo hai chiu v c hm ngc. Hm ngc l hm xy ra lc ng c cn ang quay theo chiu ny (do qun tnh), nhng li ng in cho ng c quay theo chiu ngc li m khng ch cho ng c dng hn ri mi ng in cho ng c o chiu. Hm ngc c kh nng hm nhanh v c th to m men hm ln (do s dng c hai ngun nng lng l ng nng v in nng to thnh nng lng hm), tuy vy dng in hm s ln v trong ng dng c th phi lu hn ch dng in hm ny.

S hnh 2.2 thc hin nhim v c nhim v khi ng, o chiu. Trong s c thm rle trung gian, hai rle tc (gn vi ng c), rle tc thun c tip im KT v rle tc ngc c tip im KN cc rle ny khi tc cao th cc tip im rle kn, tc thp th tip im rle h.

Khi khi ng chy thun n nt khi ng thun KT, tip im KT1 h ngn

khng cho P c in, KT3 h ngn khng cho cun ht N c in, tip im KT2 kn cp in cho cun ht T, cc tip im T1... T3 kn cp in cho ng c chy thun, tip im T4 kn t duy tr, tip im T5 h cm cun N c in.

Khi ang chy thun cn chy ngc n nt khi ng ngc KN, tip im KN1 h khng cho P c in, tip im KN2 h ct in cun ht T lm mt in ch chy thun, tip im KN3 kn cp in cho cun ht N cp in cho ch chy ngc, khi N ht tip im N4 kn t duy tr.

Nu mun dng n nt dng D, cp in cho cun ht P, cun ht P ng tip im Pl t duy tr, h P2 ct ng ngun ang cp cho cun ht T hoc N, nhng lp tc P3 kn cun ht N hoc T li c cp in, nu khi trc ng c ang chy thun (cun T lm vic) tc ang ln th KT kn, cun N c cp in ng in cho ch chy ngc lm ng c dng nhanh, khi tc gim thp th KT m ct in cun ht N, ng c dng hn.

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Khi cc rle nhit tc ng th ng c dng t do.

3. Khng ch ng c lng sc kiu i ni / c o chiu Vi mt s ng c khi lm vic nh mc ni th khi khi ng c th ni hnh

sao lm in p t vo dy cun giml(do dng in khi ng gim. S hnh 2.3 cho php thc hin i ni Y c o chiu.

Hnh 2.3. Khng ch ng c lng sc kiu i ni / c o

Trong s c khi ng t T ng in cho ch chy thun, khi ng t N ng in cho ch chy ngc, khi ng t S ng in cho ch khi ng hnh sao, khi ng t ng in cho ch chy tam gic. Rle thi gian Tg duy tr thi gian khi ng, c hai tip im Tg1 l tip im thng kn m chm thi gian t1, Tg2 l tip im thng m ng chm thi gian t2 vi t1 > t2.

Khi cn khi ng thun n nt khi ng thun KT, tip im KT2 ngn khng cho cun N c in, tip im KT1 kn ng in cho cun thun T, T c in ng cc tip im T1...T3 a in p thun vo ng c, T4 ng t duy tr, T5 m ngn khng cho N c in, T6 ng cp in cho rle thi gian Tg, ng thi cp in ngay cho cun ht S, ng c khi ng kiu ni sao, tip im S5 m cha cho cun c in. Khi Tg c in, sau thi gian ngn t2 th Tg2 ng chun b cp in cho cun ht . Sau khong thi gian duy tr t1 tip im Tg1 m ra cun ht S mt in ct ch khi ng sao ca ng c, tip im S5 kn cp in cho cun ht , a ng c vo lm vic ch ni tam gic v t duy tr bng tip im 4

Khi cn o chiu (nu ang chy thun) n nt khi ng ngc KN, T mt in lm T6 m qu trnh li khi ng theo ch ni sao nh trn vi cun ht N, cc tip im N1 ... N3 i th t hai trong ba pha (i pha A v B cho nhau) lm chiu quay i chiu.

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Khi mun ng n nt dng D, ng c dng t do.

2.3. Cc s khng ch ng c khng ng b rto dy qun

Cc bin php khi ng v thay i tc nh ng c rto lng sc cng c th p dng cho ng c rto dy qun. Nhng nh vy khng tn dng c u im ca ng c rto dy qun l kh nng thay i dng khi ng cng nh thay i tc bng cch thay i in tr ph mc vo mch rto. Do , vi ng c rto dy qun gim dng khi khi ng cng nh thay i tc ng c ngi ta dng phng php thay i in tr ph mc vo mch rto. 1. Khi ng ng c rto dy qun theo nguyn tc thi gian

Cch ny thng dng cho h thng c cng sut trung bnh v ln. S khng ch nh hnh 2.4.

Trong s c 2 rle nhit RN1 v RN2 bo v qu ti cho ng c, hai rle thi gian 1Tg v 2Tg vi hai tip im thng m ng chm duy tr thi gian loi in tr ph mch rto.

khi ng n nt khi ng K cp in cho cun ht K, cc tip im K,, K2, K3 ng cp in cho ng c, ng c khi ng vi hai cp in tr ph, tip im K4 ng t duy tr, tip im K5 ng cp in cho cc rle thi gian. Sau khong thi gian chnh nh tip im thng m ng chm 1Tg ng li cp in cho 1K loi in tr ph R2 ra khi mch rto, tip im 1K3 ng cp in cho rle thi gian 2Tg. Sau thi gian chnh nh tip im thng m ng chm 2Tg ng li cp in cho 2K loi nt in tr R1 khi mch khi ng, ng c lm vic trn c tnh c t nhin. Tip im 2K4 t duy tr, 2K5 ct in cc rle thi gian.

Khi mun dng n nt dng D, ng c c ct khi li v dng t do.

Hnh 2.4. Khi ng ng c rto dy qun theo nguyn tc thi gian

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2. Thay i tc ng c rto dy qun bng thay i in tr ph Trong cng nghip c nhiu my sn xut dng truyn ng ng c rto dy

qun iu chnh tc nh cu trc, my cn.... v y thng dng thm khu hm ng nng dng my. Hm ng nng l cch hm s dng ng nng ca ng c ang quay to thnh nng lng hm. Vi ng c rto dy qun, mun hm ng nng th khi ct in phi ni cc cun dy stato vo in p mt chiu to thnh t thng kch thch cho ng c to m men hm. S nguyn l ca h thng nh hnh 2.5.

ng c rto dy qun c th quay theo hai chiu, theo chiu thun nu 1S, 2S ng v theo chiu ngc nu 1S, 3S ng. Cng tc t H ng ngun mt chiu lc hm ng nng, cng tc t 1K, 2K ct in tr ph trong mch rto lm thay i tc ng c khi lm vic. Khi hm ng nng ton b in tr ph r1 v r2 c a vo mch rto hn ch dng in hm, cn in tr ph R trong mch mt chiu t gi tr mmen hm.

Hnh 2.5. Thay i tc ng c rto dy qun

Trong h thng c b khng ch ch huy kiu chuyn mch c kh KC. B KC c nguyn l cu to l mt tr trn c kh, c th quay hai chiu, trn trc c gn cc tip im ng v kt hp vi cc tip im tnh to thnh cc cp tip im c ng ct tu thuc vo v tr quay ca tr. th ng m tip im ca b khng ch

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KC c th hin trn hnh 2.5c. V d, v tr 0 ca b khng ch ch c tip im 1-2 ng, tt c cc v tr cn li ca cc tip im u ct hoc cp tip im 9- 1 0 s ng cc v tr 2, 3 bn tri v 2, 3 bn phi.

Hot ng ca b khng ch nh sau: khi ng in cp ngun cho h thng. Ban u b khng ch c t v tr 0 cng tc t K c in, cc tip im K mch khng ch ng li, chun b cho h thng lm vic. Nu mun ng c quay theo chiu thun th quay b KC v pha tri, nu mun ng c quay ngc th quay b KC v pha phi. Gi thit quay b KC v v tr 2 pha tri, lc ny cc tip im 3-4, 5-6, 9-10 ca b KC kn, cc cun dy cng tc t 1S, 2S, 1K v cc rle thi gian 1Tg, 2Tg c in, cc tip im 1S, 2S mch ng lc ng li, cun dy stato c ng vo ngun 3 pha, tip im 1K trong mch rto ng li ct phn in tr ph r2 ra, ng c c khi ng v lm vic vi in tr ph r1 trong mch rto, tip im 1Tg m ra, 2Tg ng li chun b cho qu trnh hm ng nng khi dng. Nu mun dng ng c th quay b KC v v tr 0, cc cng tc t 1S, 2S, 1K v cc rle thi gian 1Tg, 2Tg mt in, ng c c ct khi ngun in 3 pha vi ton b in tr r1, r2 c a vo rto, ng thi tip im thng kn ng chm 1Tg ng li (ng chm mt thi gian ngn m bo h c ct khi li in), tip im thng m m chm 2Tg cha m (t2 > t1) cng tc t H c in tip im H1, H2 ng li cp ngun mt chiu cho stato ng c v ng c c hm ng nng. Sau thi gian chnh nh t2 tip im thng m m chm m ra tng ng vi tc ng c nh, cun dy H mt in, ngun mt chiu c ct khi cun dy stato, kt thc qu trnh hm ng nng. Trong thc t, ngi ta yu cu ngi vn hnh khi quay b khng ch KC qua mi v tr phi dng li mt thi gian ngn h thng lm vic an ton c v mt in v c.

2.4. Khng ch ng c in mt chiu

Vi ng c in mt chiu khi khi ng cn thit phi gim dng khi ng. gim dng khi khi ng c th a thm in tr ph vo mch phn ng. Ngy nay nh k thut in t v tin hc pht trin ngi ta ch to cc b bin i mt chiu bng bn dn cng sut ln lm ngun trc tip cho ng c v iu khin cc b bin i ny bng mch s logic kh trnh. Cc b bin i ny ni trc tip vo ng c, vic khng ch khi ng, hm v iu chnh tc u thc hin bng cc mch s kh trnh rt thun tin v linh hot. Tuy nhin, mt s mch n gin vn c th dng s cc mch logic nh hnh 2.6.

khi ng ng c n nt khi ng K lc cng tc t K c in, cc tip im thng m K, ng li cp in cho ng c vi 2 in tr ph, K2 ng li t duy tr, K3 ng li, K4 m ra lm rle thi gian 3Tg mt din, sau thi gian chnh nh tip im thng ng ng chm 3Tg, ng li lm cng tc t 1K c in, ng tip im 1K1 loi in tr ph r2 khi mch ng c v lm rle thi gian

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2Tg mt in, sau thi gian chnh nh tip im thng ng ng chm 2Tg1 ng li cp in cho cng tc t 2K ng tip im 2K2 loi r1 ra khi mch ng lc qu trnh khi ng kt thc.

Hnh 2.6. Khng ch ng c in mt chiu

dng ng c n nt dng D lc cng tc t K mt in, tip im K1 mch ng lc m ra ct phn ng ng c khi ngun in. ng thi tip im K2 K3 m ra lm rle thi gian 1 Tg mt in bt u tnh thi gian hm, K4 ng li lm cng tc t H c in ng tip im H1 a in tr hm Rh vo thc hin qu trnh hm. Sau thi gian chnh nh tip im thng m m chm 1 Tg1 m ra, cng tc t H mt in kt thc qu trnh hm, h thng khng ch v mch ng lc tr v trng thi ban u chun b cho ln khi ng sau.

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PHN 2: IU KHIN LOGIC C LP TRNH (PLC)

CHNG 3: L LUN CHUNG V IU KHIN LOGIC LP TRNH PLC

3.1. M u

S pht trin ca k thut iu khin t ng hin i v cng ngh iu khin logic kh trnh da trn c s pht trin ca tin hc m c th l s pht trin ca k thut my tnh.

K thut iu khin logic kh trnh PLC (Programmable Logic Control) c pht trin t nhng nm 1968 -1970. Trong giai on u cc thit b kh trnh yu cu ngi s dng phi c k thut in t, phi c trnh cao. Ngy nay cc thit b PLC pht trin mnh m v c mc ph cp cao.

Thit b iu khin logic lp trnh c PLC l dng thit b iu khin c bit da trn b vi x l, s dng b nh lp trnh c lu tr cc lnh v thc hin cc chc nng, chng hn cho php tnh logic, lp chui, nh gi, m, v cc thut ton iu khin my v cc qu trnh cng ngh. PLC c thit k cho cc k s, khng yu cu cao v kin thc my tnh v ngn ng my tnh, c th vn hnh. Chng c thit k cho cc nh k thut c th ci t hoc thay i chng trnh. V vy, cc nh thit k PLC phi lp trnh sn sao cho chng trnh iu khin c th nhp bng cch s dng ngn ng n gin (ngn ng iu khin). Thut ng logic c s dng v vic lp trnh ch yu lin quan n cc hot ng logic, v d nu c cc iu kin A v B th C lm vic... Ngi vn hnh nhp chng trnh (chui lnh) vo b nh PLC. Thit b iu khin PLC s gim st cc tn hiu vo v cc tn hiu ra theo chng trnh ny v thc hin cc quy tc iu khin c lp trnh.

Cc PLC tng t my tnh, nhng my tnh c ti u ho cho cc tc v tnh ton v hin th, cn PLC c chuyn bit cho cc tc v iu khin v mi trng cng nghip. V vy cc PLC:

+ c thit k bn chu c rung ng, nhit, m v ting n, + C sn giao din cho cc thit b vo ra, + c lp trnh d dng vi ngn ng iu khin d hiu, ch yu gii quyt cc

php ton logic v chuyn mch. V c bn chc nng ca b iu khin logic PLC cng ging nh chc nng ca

b iu khin thit k trn c s cc rle cng tc t hoc trn c s cc khi in t l:

+ Thu thp cc tn hiu vo v cc tn hiu phn hi t cc cm bin, + Lin kt, ghp ni cc tn hiu theo yu cu iu khin v thc hin ng m

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cc mch ph hp vi cng ngh, + Tnh ton v son tho cc lnh iu khin trn c s so snh cc thng tin thu

thp c, + Phn pht cc lnh iu khin n cc a ch thch hp. Ring i vi my cng c v ngi my cng nghip th b PLC c th lin kt

vi b iu khin s NC hoc CNC hnh thnh b iu khin thch nghi. Trong h thng ca cc trung tm gia cng, mi quy trnh cng ngh u c b PLC iu khin tp trung.

3.2. Cc thnh phn c bn ca mt b PLC

1. Cu hnh phn cng B PLC thng dng c nm b phn c bn gm: b x l, b nh, b ngun,

giao din vo/ra v thit b lp trnh. S h thng nh hnh 3.1 . 1.1 B x l

B x l cn gi l b x l trung tm (CPU), l linh kin cha b vi x l. B x l bin dch cc tn hiu vo v thc hin cc hot ng iu khin theo chng trnh c lu trong b nh ca CPU, truyn cc quyt nh di dng tn hiu hot ng n cc thit b ra.

Nguyn l lm vic ca b x l tin hnh theo tng bc tun t, u tin cc thng tin lu tr trong b nh chng trnh c gi ln tun t v c kim sot bi b m chng trnh. B x l lin kt cc tn hiu v a kt qu iu khin ti u ra. Chu k thi gian ny gi l thi gian qut (scan). Thi gian mt vng qut ph thuc vo dung lng ca b nh, vo tc ca CPU. Ni chung chu k mt vng qut nh hnh 3.2.

S thao tc tun t ca chng trnh dn dn mt thi gian tr trong khi b m ca chng trnh i qua mt chu trnh y , sau bt u li t u.

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nh gi thi gian tr ngi ta o thi gian qut ca mt chng trnh di 1K byte v coi l ch tiu so snh cc PLC. Vi nhiu loi PLC thi gian tr ny c th ti 20ms hoc hn. Nu thi gian tr gy tr ngi cho qu trnh iu khin th phi dng cc bin php c bit, chng hn nh lp li nhng ln gi quan trng trong thi gian mt ln qut, hoc l iu khin cc thng tin chuyn giao b bt i nhng ln gi t quan trng khi thi gian qut di ti mc khng th chp nhn c. Nu cc gii php trn khng tho mn th phi dng PLC c thi gian qut ngn hn. 1. 2. B ngun

B ngun c nhim v chuyn i in p AC thnh in p thp cho b vi x l (thng l 5V) v cho cc mch in u ra hoc cc module cn li (thng l 24V). 1.3. Thit b lp trnh

Thit b lp trnh c s dng lp cc chng trnh iu khin cn thit sau c chuyn cho PLC. Thit b lp trnh c th l thit b lp trnh chuyn dng, c th l thit b lp trnh cm tay gn nh, c th l phn mm c ci t trn my tnh c nhn. 1.4. B nh

B nh l ni lu gi chng trnh s dng cho cc hot ng iu khin. Cc

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dng b nh c th l RAM, ROM, EPROM. Ngi ta lun ch to ngun d phng cho RAM duy tr chng trnh trong trng hp mt in ngun, thi gian duy tr tu thuc vo tng PLC c th. B nh cng c th c ch to thnh module cho php d dng thch nghi vi cc chc nng iu khin c kch c khc nhau, khi cn m rng c th cm thm. 1.5. Giao din vo/ra

Giao din vo l ni b x l nhn thng tin t cc thit b ngoi vi v truyn thng tin n cc thit b bn ngoi. Tn hiu vo c th t cc cng tc, cc b cm bin nhit , cc t bo quang in.... Tn hiu ra c th cung cp cho cc cun dy cng tc t, cc rle, cc van in t, cc ng c nh... Tn hiu vo/ra c th l tn hiu ri rc, tn hiu lin tc, tn hiu logic... Cc tn hiu vo/ra c th th hin nh hnh 3.3.

Mi im vo ra c mt a ch duy nht c PLC s dng.

Hnh 3.3: Giao din vo/ra

Cc knh vo/ra c cc chc nng cch ly v iu ho tn hiu sao cho cc b cm bin v cc b tc ng c th ni trc tip vi chng m khng cn thm mch in khc.

Tn hiu vo thng c ghp cch in (cch ly) nh linh kin quang nh hnh 3.4. Di tn hiu nhn vo cho cc PLC c ln c th l 5v, 24v, 110v, 220v. Cc PLC c nh thng ch nhp tn hiu 24v.

Tn hiu ra cng c ghp cch ly, c th cch ly kiu rle nh hnh 3.5a, cch

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ly kiu quang nh hnh 3.5b. Tn hiu ra c th l tn hiu chuyn mch 24v, 100mA; 110v, 1A mt chiu, thm ch 240v, 1A xoay chiu tu loi PLC. Tuy nhin, vi PLC c ln di tn hiu ra c th thay i bng cch la chn cc module ra thch hp.

2. Cu to chung ca PLC

Cc PLC c hai kiu cu to c bn l: kiu hp n v kiu modulle ni ghp. Kiu hp n thng dng cho cc PLC c nh v c cung cp di dng

nguyn chic hon chnh gm b ngun, b x l, b nh v cc giao din vo/ra. Kiu hp n thng vn c kh nng ghp ni c vi cc module ngoi m rng kh nng ca PLC. Kiu hp n nh hnh 3.6.

Kiu module ghp ni gm cc module ring cho mi chc nng nh module

ngun, module x l trung tm, module ghp ni, module vo/ra, module m, module PID... cc module c lp trn cc rnh v dc kt ni vi nhau. Kiu cu to ny c th c s dng cho cc thit b iu khin lp trnh vi mi kch c, c nhiu b chc nng khc nhau c gp vo cc module ring bit. Vic s dng cc module tu thuc cng dng c th. Kt cu ny kh linh hot, cho php m rng s lng u ni vo/ra bng cch b sung cc module vo/ra hoc tng cng b nh bng cch tng thm cc n v nh.

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3.3. Cc vn v lp trnh

1 Khi nim chung PLC c th s dng mt cch kinh t hay khng ph thuc rt ln vo thit b lp

trnh. Khi trang b mt b PLC th ng thi phi trang b mt thit b lp trnh ca cng mt hng ch to. Tuy nhin, ngy nay ngi ta c th lp trnh bng phn mm trn my tnh sau chuyn sang PLC bng mch ghp ni ring.

S khc nhau chnh gia b iu khin kh trnh PLC v cng ngh rle hoc bn dn l ch k thut nhp chng trnh vo b iu khin nh th no. Trong iu khin rle, b iu khin c chuyn i mt cch c hc nh u ni dy "iu khin cng", cn vi PLC th vic lp trnh c thc hin thng qua mt thit b lp trnh v mt ngoi vi chng trnh. C th ch ra quy trnh lp trnh theo gin hnh 3.8.

lp trnh ngi ta c th s dng mt trong cc m hnh sau y:

Hnh 3.8. Quy trnh lp trnh

+ M hnh dy. + M hnh cc chc nng. + M hnh biu ni dy. + M hnh logic. Vic la chn m hnh no trong cc m hnh trn cho thch hp l tu thuc vo

loi PLC v iu quan trng l chn c loi PLC no cho php giao lu tin li v trnh c chi ph khng cn thit. a s cc thit b PLC lu hnh trn th trng hin nay l dng m hnh dy hoc biu ni dy. Nhng PLC hin i cho php ngi dng chuyn t mt phng php nhp ny sang mt phng php nhp khc ngay trong qu trnh nhp.

Trong thc t khi s dng biu ni dy th vic lp trnh c v n gin hn v n c cch th hin gn ging nh mch rle cng tc t. Tuy nhin, vi nhng ngi c sn nhng hiu bit c bn v ngn ng lp trnh th li cho rng dng m hnh dy d dng hn, ng thi vi cc mch c ln th dng m hnh dy c nhiu u im hn.

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Mi nh ch to u c nhng thit k v phng thc thao tc thit b lp trnh ring, v th khi c mt loi PLC mi th phi c thi gian v cn phi c hun luyn lm quen vi n. 2. Cc phng php lp trnh

T cc cch m t h t ng cc nh ch to PLC son tho ra cc phng php lp trnh khc nhau. Cc phng php lp trnh u c thit k n gin, gn vi cc cch m t c bit n. T ni chung c ba phng php lp trnh c bn l phng php bng lnh STL, phng php biu bc thang LAD v phng php lu iu khin CSF. Trong , hai phng php bng lnh STL v biu bc thang LAD c dng ph bin hn c. 2.1. Mt s k hiu chung Cu trc lnh

Mt lnh thng c ba phn chnh v thng vit nh hnh 3.9 (c loi PLC c cch vit hi khc):

1. a ch tng i ca lnh (thng khi tp trnh thit b lp trnh t a ra). 2. Phn lnh l ni dung thao tc m PLC phi tc ng ln i tng ca lnh,

trong lp trnh LAD th phn ny t th hin trn thanh LAD, khng c ghi ra. 3. i tng lnh, l phn m lnh tc ng theo yu cu iu khin, trong i

tng lnh li c hai phn: 4. Loi i tng, c trng hp sau loi i tng c du ":", c cc loi i

tng nh tn hiu vo, tn hiu ra, c (rle ni)... 5. Tham s ca i tng lnh xc nh c th i tng, cch ghi tham s

cng ph thuc tng loi PLC khc nhau.

K hiu thng c trong mi lnh:

Cc k hiu trong lnh, quy c cch vit vi mi quc gia c khc nhau, thm ch mi hng, mi thi ch to ca hng c th c cc k hiu ring. Tuy nhin, cch ghi chung nht cho mt s quc gia l:

M: + K hiu u vo l I (In), u ra l Q (out trnh nhm O l khng). + Cc lnh vit gn ting Anh v d ra l out. + Lnh ra (gn) l out. + Tham s ca lnh dng c s 10.

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+ Pha trc i tng lnh c du %. + Gia cc s ca tham s khng c du chm.

V d: AND% I09; out%Q10.

Nht: + u vo k hiu l X, u ra k hiu l Y. + Cc lnh hu nh c vit tt t ting Anh. + Lnh ra (gn) l out. + Tham s ca lnh dng c s 8.

V d: A X 10; out Y 07

Ty c + u vo k hiu l I, u ra k hiu l Q. + Cc lnh hu nh c vit tt t ting Anh. + Lnh ra (gn) l = + Tham s ca lnh dng c s 8. + Gia cc s ca tham s c du chm phn bit khe v knh.

V d: A I 1.0; = Q 0.7. Ngoi cc k hiu kh chung nh trn th mi hng cn c cc k hiu ring, c

b lnh ring. Ngay cng mt hng cc thi ch to khc nhau cng c c im khc nhau vi b lnh khc nhau. Do , khi s dng PLC th mi loi PLC phi tm hiu c th hng dn s dng ca n.

Mt s k hiu khc nhau vi cc lnh c bn c th hin r trn bng 3.1. 2.2. Phng php hnh thang LAD (Ladder Logic)

Phng php hnh thang c dng ca biu nt bm. Cc phn t c bn ca phng php hnh thang l:

+ Tip im: thng m Thng kn + Cun dy (m t cc rle)

+ Hp (m t cc hm khc nhau, cc lnh c bit) Bng 3.1

IEC 1131-3

Misubishi OMRON Siemens Telemec- anique

Spreher v Schuh

Ch thch

LD LD LD A L STR Khi u vi tip im thng m

LDN LDI LD NOT AN LN STR NOT

Khi u vi tip im thng kn

AND AND AND A A AND Phn t ni tip c tip im m

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IEC 1131-3

Misubishi OMRON Siemens Telemec- anique

Spreher v Schuh

Ch thch

ANDN ANI AND NOT

AN AN AND NOT

Phn t ni tip c tip im kn

O OR OR O O OR Phn t song song c tiu im m

ORN ORI OR NOT ON ON OR NOT Phn t song song c tip im kn

ST OUT OUT =

=

OUT Ly tn hiu ra

Mng LAD l ng ni cc phn t thnh mt mch hon chnh, theo th t t tri sang phi, t trn xung di. Qu trnh qut ca PLC cng theo th t ny. Mi mt nc thang xc nh mt s hot ng ca qu trnh iu khin. Mt s LAD c nhiu nc thang. Trn mi phn t ca biu hnh thang LAD c cc tham s xc nh tu thuc vo k hiu ca tng hng sn xut PLC. V d: Mt nc ca phng php hnh thang nh hnh 3.10.

Hnh 3.10. Phng php lp trnh thang LAD

Hnh 3.10a l kiu k hiu ca Misubishi (Nht) Hnh 3.10b l kiu k hiu ca Siemens (Ty c)

Hnh 3.10c l k hiu ca Allen Bradley 2.3. Phng php lit k 1nh STL (Statement List)

Phng php STL gn vi biu logic. phng php ny cc lnh c lit k th t. Tuy nhin, phn bit cc on chng trnh ngi ta thng dng cc m nh, mi m nh tng ng vi mt nc thang ca biu hnh thang. khi u mi on (tng ng nh khi u mt nc thang) khi lp lun s dng cc lnh khi u nh LD, L, A, O... (bng 3.l). Kt thc mi on thng l lnh gn cho u ra, u ra c th l u ra cho thit b ngoi vi c th l u ra cho cc rle ni. V d: Mt on STL ca PLC S5 (Siemens)

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Mt on STL ca PLC S7-200 (Siemens) 0 LD I 0.1 1 A I 0.2 3 = Q 1.0

Mt on STL ca PLC MELSEC Fl (Nht) 0 LD X 400 1 O X 403 2 ANI X 404 3 OUT Y 433

Mt on STL ca CPM1A (OMRON) 0 LD 000.01 1 OR 010.00 2 AND NOT 000.00 3 AND 000.03 4 OUT 010.00

2.4. Phng php lu iu khin CSF (Control System Flow) Phng php lu iu khin CSF trnh by cc php ton logic vi cc k

hiu ho c tiu chun ho nh hnh 3.15. Phng php lu iu khin thch hp vi ngi quen vi php tnh iu khin bng i s Boo1e.

Hnh 3.15. Phng php lp trnh CSF

3. Cc rle ni Trong cc loi PLC c nhiu thut ng dng ch cc linh kin loi ny, v d:

rle ph, b vch du, c hiu, lu tr bt, bt nh... y l linh kin cung cp cc chc nng c bit gn lin vi PLC v c dng ph bit trong lp trnh. Rle ni ny tng t nh cc rle trung gian trong s rle cng tc t. Rle ni cng c coi l cc u ra nhn cc lnh gn u ra, nhng thc cht u ra ny khng a ra ngoi (khng phi thit b ngoi vi) m ch nm ni ti trong PLC. PLC nh c th c ti hng trm rle ni, cc rle ni u c nui bng ngun d phng khi mt in.

Mt s k hiu cc rle ni:

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Hng Tn gi K hiu V d

Misubishi Rle ph hoc b nh du M M100; M101

Siemens C hiu F F0.0; F0.1

Sprecher v Schuh Cun dy C C001; C002

TelemecaniQue Bt B B0; B1

Toshiba Rle ni R R000; R001

Bradley Lu tr bt B B3/001 ; B3/002

V d: S dng rle ni (ca Misibishi)

0 LD X 400 1 OR X 403 2 ANI X 404 3 OUT M 100 4 LD M 100 5 AND X 401 6 OUTY 433

4. Cc rle thi gian Trong cc h thng iu khin lun lun phi s dng rle thi gian duy tr

thi gian cho qu trnh iu khin. Trong cc PLC ngi ta cng gn cc rle thi gian vo trong . Tuy nhin, thi gian y c xc nh nh ng h trong CPU. Cc rle thi gian cng c cc tn gi khc nhau nhng thng gi nht l b thi gian (Time).

Cc nh sn xut PLC khng thng nht v cch lp trnh cho cc rle thi gian ny. Mi loi PLC (thm ch trong cng hng) cng c cc k hiu v cch lp trnh rt khc nhau cho rle thi gian. S lng rle thi gian trong mi PLC cng rt khc nhau.

im chung nht i vi cc rle thi gian l cc hng u coi rle thi gian l cc u ra ni, do rle thi gian l u ra ca nc thang, hay ca mt on chng trnh. 5. Cc b m

B m cho php m tn sut xut hin tn hiu vo. B m c th c dng trong trng hp m cc sn phm di chuyn trn bng chuyn v s sn phm xc nh cn chuyn vo thng. B m c th m s vng quay ca trc, hoc s ngi i qua ca. Cc b m ny c ci t sn trong PLC.

C hai loi b m c bn l b m tin v b m li. Cc nh sn xut PLC cng s dng cc b m theo nhng cch khc nhau. Tuy nhin, cng nh cc b thi gian, b m cng c coi l u ra ca PLC v y cng l u ra ni, xut tn

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hiu ra ngoi phi qua u ra ngoi vi (c chn ni ra ngoi PLC).

3.4. nh gi u nhc im ca PLC

Trc y, b PLC thng rt t, kh nng hot ng b hn ch v quy trnh lp trnh phc tp. V nhng l do m PLC ch c dng trong nhng nh my v cc thit b c bit. Ngy nay do gim gi lin tc, km theo tng kh nng ca PLC dn n kt qu l ngy cng c p dng rng ri cho cc thit b my mc. Cc b PLC n khi vi 24 knh u vo v 16 knh u ra thch hp vi cc my tiu chun n, cc trang thit b lin hp. Cn cc b PLC vi nhiu kh nng ng dng v la chn c dng cho nhng nhim v phc tp hn.

C th k ra cc u im ca PLC nh sau: + Chun b vo hot ng nhanh: Thit k kiu module cho php thch nghi

nhanh vi mi chc nng iu khin. Khi c lp ghp th PLC sn sng lm vic ngay. Ngoi ra n cn c s dng li cho cc ng dng khc d dng.

+ tin cy cao: Cc linh kin in t c tui th di hn cc thit b c-in. tin cy ca PLC ngy cng tng, bo dng nh k thng khng cn thit cn vi mch rle cng tc t th vic bo dng nh k l cn thit.

+ D dng thay i chng trnh: Nhng thay i chng trnh c tin hnh n gin. sa i h thng iu khin v cc quy tc iu khin ang c s dng, ngi vn hnh ch cn nhp tp lnh khc, gn nh khng cn mc ni li dy (tuy nhin, c th vn phi ni li nu cn thit). Nh h thng rt linh hot v hiu qu.

+ nh gi nhu cu n gin: Khi bit cc u vo v cc u ra th c th nh gi c kch c yu cu ca b nh hay di chng trnh. Do , c th d dng v nhanh chng la chn PLC ph hp vi cc yu cu cng ngh t ra.

+ Kh nng ti to: Nu dng nhiu PLC vi quy cch k thut ging nhau th chi ph lao ng s gim thp hn nhiu so vi b iu khin rle, l do gim phn ln lao ng lp rp.

+ Tit kim khng gian: PLC i hi t khng gian hn so vi b iu khin rle tng ng.

+ C tnh cht nhiu chc nng: PLC c u im chnh l c th s dng cng mt thit b iu khin c bn cho nhiu h thng iu khin. Ngi ta thng dng PLC cho cc qu trnh t ng linh hot v d dng thun tin trong tnh ton, so snh cc gi tr tng quan, thay i chng trnh v thay i cc thng s.

+ V gi tr kinh t: Khi xt v gi tr kinh t ca PLC phi cp n s lng u ra v u vo. Quan h v gi thnh vi s lng u vo/ra c dng nh hnh 3.17. Trn hnh 3.17 th hin, nu s lng u vo/ra qu t th h rle t ra kinh t hn, nhng khi s lng u vo/ra tng ln th h PLC kinh t hn hn.

48

Khi tnh n gi c ca PLC th khng th khng k n gi ca cc b phn ph

khng th thiu nh thit b lp trnh, my in, bng ghi... c vic o to nhn vin k thut. Ni chung nhng phn mm thit k lp trnh cho cc mc ch c bit l kh t. Ngy nay nhiu hng ch to PLC cung cp chn b ng gi phn mm c th nghim, nhng vic thay th, sa i cc phn mm l nhu cu khng th trnh khi, do , vn cn thit phi c k nng phn mm.

Phn b gi c cho vic lp t mt PLC thng nh sau: - 50% cho phn cng ca PLC. - 10% cho thit k khun kh chng trnh. - 20% cho son tho v lp trnh. - 15% cho chy th nghim. - 5% cho ti liu. Vic lp t mt PLC tip theo ch bng khong 1/2 gi thnh ca b u tin,

ngha l hu nh ch cn chi ph phn cng. C th so snh h iu khin rle v h iu khin PLC nh sau: H rle:

+ Nhiu b phn c chun ho. + t nhy cm vi nhiu. + Kinh t vi cc h thng nh. - Thi gian lp t lu. - Thay i kh khn

- Kh theo di v kim tra cc h thng ln, phc tp. - Cn bo qun thng xuyn. - Kch thc ln.

H PLC + Thay i d dng qua cng ngh phch cm. + Lp t n gin. + Thay i nhanh quy trnh iu khin. + Kch thc nh. + C th ni vi mng my tnh.

- Gi thnh cao B thit b lp trnh thng t, s dng t.

49

CHNG 4: B IU KHIN PLC CPM1A

4.l. Cu hnh cng

1. Cu to ca h PLC CPM1A PLC CPM1A thuc h OMRON do Nht bn sn xut. y l loi PLC n

khi c th lp ghp thm cc module v lp ghp nhiu PLC vi nhau. n v c bn ca PLC CPM1A nh hnh 4.1 .

Trong :

1. Cc n bo h thng: + n PWR (xanh): bo ngun, + n RUN (xanh): PLC ang ch chy hoc kim tra, (n tt th PLC

ang ch lp trnh hoc c li), + n ERR/ALM (): + Sng: C li, PLC khng hot ng,

+ Nhp nhy, hoc tt: PLC ang hot ng, + COMM (da cam): D liu ang c truyn ti cng ngoi vi.

2. Cng ghp ni vi my tnh hoc thit b lp trnh (c np y). 3. Cc n ch th v a ch ra, (sng nu c tn hiu ra). 4. Chn ni cho u ra (c np y). 5. Cc n ch th v a ch vo, (sng nu c tn hiu vo). 6. Chn ni cho u vo (c np y). 2. Cc thng s k thut 2.1. Cc loi CPM1A

50

Trong h CPM1A c cc PLC sau:

M hiu Ngun cung cp S u vo S u ra Tng s I/OCPM1A-10CDR-A AC CPM1A-10CDR-D DC

6 4 10

CPM1A-20CDR-A AC CPM1A-20CDR-D DC

12 8 20

CPM1A-30CDR-A AC CPM1A-30CDR-D AD

18 12 30

CPM1A-40CDR-A AC CPM1A-40CDR-D DC

24 16 40

2.2. Thng s chung Mc 10-u I/O 20-u I/O 30-u I/O 40-u I/O

Kiu AC 100 n 240v AC, 50/60 Hz in p cung cp Kiu DC 24v DC

Kiu AC 85 n 264 v AC Phm vi in p Kiu DC 20,4 n 26,4v DC

Kiu AC max 30 VA max 60 VA Tiu th in Kiu DC max 6 W max 20 W Dng in max 30 A max 60 A

p 24 VDC Ngun cp ra (ch c kiu AC) dng 200 mA 300 mA in tr cch ly 20 M min. (ti 500v DC) gia cc AC v cc tip a. bn xung lc 147m/s2 (20G) ba ln mi chiu X, Y v Z Nhit mi trng Nhit lm vic: 0 n 55Co

Nhit bo qun: -20 n 75Co m mi trng 10% to 90% (with no condensation) Mi trng lm vic Khng lm vic trong mi trng kh t Thi gian cho gin on ngun

Kiu AC: min 10ms; Kiu DC: min 2ms. (Thi gian gin on tnh khi ngun nh hn 85% nh mc)

Kiu AC Max 400 g Max 500 g Max 600 g Max 700 g Trong lng CPU Kiu DC Max 300 g Max 400 g Max 500 g Max 600 g

2.3 Cc c trng

Mc 10 - u I/O 20 - u I/O 30 - u I/O 40 - u I/O di lnh T 1 n 5 t cho 1 lnh Kiu lnh Lnh c bn: 14; lnh c bit: 77 kiu, tng 135 lnh Thi gian thc hin Lnh c bn: 0,72 n 16,2 s

Lnh c bit: 12,375 s (lnh MOV) Dung lng chng trnh 2.048 t (Words)

Ch CPU 6 input 4 output

12 input 8 output

18 input 12 output

24 input 16 output

Vo ra cc i

C module m rng

---- ---- 54 input 36 output

60 input 40 output

51

Mc 10 - u I/O 20 - u I/O 30 - u I/O 40 - u I/O Vo dng bt 00000 n 00915 (Words 0 n 9) Ra dng bt 01000 n 01915 (Words 10 to 19) T bt (vng IR ) 5 1 2 bts : IR20000 to 23115 (words IR 200 to IR 231 ) Bt c bit (vng SR) 384 bts: SR 23200 to 25515 (words SR 232 to IR 255) Bt nh tm thi (vng TR)

8 bts (TR0 to TR7)

Bt gi (vng HR) 320 bts: HR 0000 to HR 1915 (words HR 00 to HR 19) Bt b tr (Vng AR) 256 bts:AR 0000 to AR 1515 (words AR 00 to AR 15) Bt lin kt (vng LR) 256 bts : LR 0000 to LR 1515 (words LR 00 to LR 15 ) Timers/Cunters 128 Timers/counters (TIM/CNT 000 to TIM/CNT 127)

100 - ms Timers: TIM 000 to TIM 127 10 - ms Timers: TIM 00 to TIM 127

Nh d liu Read/write: 1.024 words (DM 0000 to DM 1023 ) Read-only: 512 words (DM 6144 to DM 6655)

X l ngt 2 im (thi gian phn ng: Max 0,3 ms.)

4 im (thi gian phn ng: Max: 0,3 ms)

Bo v b nh HR, AR, S liu trong vng nh ni dung v s m c bo v khi ngun b gin on.

Sao lu b nh T in d phng: s liu nh (c/vit), bt gi, bt nh b tr, b m (20 ngy trong iu kin nhit 25oC)

Chc nng t chun on CPU b hng, I/O li ng dn, li b nh. Chng trnh kim tra Khng c lnh kt thc, li ca chng trnh (lin tc kim

tra trong thi gian lm vic) B m tc cao 1 b: 5 kHz 1 pha, hoc 2.5 kHz 2 pha

Kiu tng dn: 0 n 65.535 (16 bts) Kiu tng/gim: -32.767 n 32.767 (16 bts)

Nhp hng s thi gian C th t 1 ms, 2 ms, 4 ms, 8 ms, 16 ms, 32 ms, 64 ms, hoc 128 ms

t tn hiu analog 2 ng (0 n 200 BCD) 2.4. Cu trc vng nh

D liu T (words) Bt Chc nng IR vo IR 000 n IR 009 (10

words) IR 00000 n IR 00915 (160 bts )

Ra IR 010 n IR 019 (10 words)

IR 01000 n IR 01915 (160 bts)

Cc bt ny c th lm vic vng vo ra m rng

lm vic

Ir 200 n IR 231 (32 words)

Ir 20000 n IR to 23 115 (5 2 bts)

Cc t bt ny c th s dng tu trong chng trnh

SR SR 232 n SR 255 (24 words)

SR 23200 n 25515 (384 bts)

Nhng bt ny phc v cho chc nng c bit nh c v bt iu khin.

TR --- TR 0 n TR 7 (8 bts) Bt ny c s dng trng thi ng m trong chng trnh phn nhnh

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D liu T (words) Bt Chc nng HR HR 00 n HR 19 (20

words) HR 0000 dn HR 1915 (320 bts)

Nhng bt ny lu gi trng thi ng m khi mt ngun ngoi.

Ar AR 00 n HR 15 (1 6 words)

AR 0000 n HR 1515 (256 bts)

Nhng bt ny phc v cho chc nng c bit nh c v bt iu khin.

LR LR 00 n LR 15 (16 words)

LR 00000 n LR 1515 (256 bts )

S dng kt ni vi PC khc

Timer/ couter

TC 000 n TC 127 (timer/counter) S ging nhau s dng cho c thu v couter.

DM c /vit

DM 0000 DM 0999 DM 1022 DM 1023(1,002 words)

--- DM l d liu ch truy cp dng t (words). Cc d liu dng t (words) c ct gi khi mt ngun.

Ghi li

DM 1000 n DM 1021 (22 words)

--- S dng ghi thi gian s c v li xut hin. T y c th c/ghi khi li xut hin.

Ch c

DM 6144 n DM 6599 (456 words)

- - Khng th ghi ln chng trnh

Ci t PC

Di 6600 n DM 6655 (%6 words)

- s dng n nhiu vng tham s iu khin lm vic ca PC

Ch : 1. Bt IR v LR khi cha s dng cho cc chc nng chnh th c th s dng nh bt lm vic. 2. Ni dung ca vng HR, LR, Counter, v vng c/ghi DM c th c lu gi bng t in nhit 25oC, vi thi gian 20 ngy. 3. Khi truy nhp cc s PV, TC th d liu dng t (words), khi truy cp vo c th d liu dng bt. 4. D liu trong DM 6144 n DM 6655 khng th ghi t chng trnh nhng c th thay i t thit b ngoi "Peripheral Device". 2.5. Cc vo ra - cc bt vng IR cho vo ra m rng

Bng sau cho bit cc bt vng IR dng cho module vo ra m rng ca CPM1A v cc loi module m rng.

im ni CPU (a ch)

im ni vng m rng (a ch) S vo/ra ca CPU

Vo Ra Vo Ra Ngun S module

AC CPM1A-10CDR-A 10

6 im: 00000 00005

4 im:01000 01003

---

--- DC CPM1A-10CDR-D

AC CPM1A-20CDR-A 20

12 im: 00000 00011

8 im : 01000 01007

---

--- DC CPM1A-20CDR-D

53

im ni CPU (a ch)

im ni vng m rng (a ch) S vo/ra ca CPU

Vo Ra Vo Ra Ngun S module

AC CPM1A-30CDR-A

30

18 im: 00000 00011 00100 00105

12 im: 01000 01007 01100 01103

DC CPM1A-30CDR-D

AC CPM1A-40CDR-A 40

20 im: 00000 00011 00100 00111

16 im :01000 11007 01100 01107

36 im:00200 00211 00300 00311 00400 00411

24 im: 01200 01207 01300 01307 01400 01407

DC CPM1A-40CDR-D

4.2. Ghp ni

PLC CPM1A c th ghp ni vi 32 b PLC cng loi thnh h thng. lp trnh cho PLC th c th ghp ni n vi thit b lp trnh cm tay, b lp trnh chuyn dng hoc my tnh tng thch.

1. Ghp ni vi thit b lp trnh cm tay: Ni trc tip cp ca thit b cm tay vo PLC nh hnh 4.2.

Hnh 4.2. Ghp ni PLC vi thit b lp trnh cm tay

2. Ghp ni vi thit b lp trnh chuyn dng hoc my tnh tng thch

Khi ghp ni vi my tnh tng thch ngi ta dng cp ni chun RS-232C v

54

b phi hp RS-232 (hoc RS-422) hoc cp chuyn i loi CQMI-CIF02. Ghp ni vi thit b lp trnh chuyn dng nh hnh 4.3. PLC c ghp ni vi cng ni tip (COM) ca my tnh.

3. Ghp ni nhiu PLC v my tnh C th ghp thnh h thng nh ni cc PLC - CPM1A vi nhau, s PLC -

CPM1A c th ghp ti a l 32, h thng ny c th ni vi my tnh tng thch, s nh hnh 4.4. Chiu di ln nht cho php ca cp RS-422 l 500 m.

PLC - CPM 1 A

Hnh 4.4. Ghp ni nhiu PLC

4.3. Ngn ng lp trnh

1. Cu trc chng trnh PLC CPM1A Cc chng trnh iu khin vi PLC CPM1A c th c vit dng n khi

hoc a khi. Chng trnh n khi Chng trnh n khi ch vit cho cc cng vic t ng n gin, cc lnh

c vit tun t trong mt khi. Khi vit chng trnh n khi ngi ta dng khi OBI. B PLC qut khi theo chng trnh, sau khi qut n lnh cui cng n quay tr li lnh u tin.

Chng trnh a khi (c cu trc) Khi nhim v t ng ho phc tp ngi ta chia chng trnh iu khin ra

thnh tng phn ring gi l khi. Chng trnh c th xp lng khi ny vo khi kia. Chng trnh ang thc hin khi ny c th dng lnh gi khi sang lm vic

55

vi khi khc, sau khi kt thc cng vic khi mi n quay v thc hin tip chng trnh tm dng khi c. 2. Bng lnh ca PLC PCM1A

Xem phn "Bng lnh" ph lc 2 3. Lp trnh cc lnh logic c bn ca PLC PCM1A

Vi PLC ny c: 12 u vo vi a ch xc nh t 000.00 n 000.11. 8 u ra vi a ch xc nh t 010.00 n 010.07.

Khi lp trnh phn mm lp trnh t hiu cc a ch trn, khng cn a khi nim phn bit vo/ra. Nu a thm khi nim vo/ra (X/Y) phn mm s khng chp nhn.

Kt thc chng trnh phi c lnh kt thc END chng trnh mi chy. 3.1. Lnh AND

Lp trnh dng LAD (c th lp trnh dng STL v kim tra li dng LAD). LD 000.00 AND 000.03 AND 000.04 OUT 010.00 + Xem li chng trnh t

biu tng (phn ph lc 1) + Chn trng thi MONITOR hoc trng thi PROGRAM (STOP/PRG) nh

Shift + F10 hoc biu tng "PLC Mode". chng trnh sang PLC t biu tng hoc t ng dn (nh ph lc l).

+ Chn trng thi MONITOR hoc trng thi RUN nh Shift + F10 hoc biu tng "PLC Mode" chy chng trnh. 3.2. Lnh AND NOT

Dng STL LD 000.03 AND NOT 000.00 AND 000.04 OUT 010.00 END

3.3. Lnh OR: Dng SLT LD 000.03 OR 000.04 OR 000.05

56

OUT 010.02 END

3.4. Lnh OR NOT Dng STL LD 00.03 OR NOT 00.04 OR 000.05 OUT 010.02 END

3. 5. Lnh OR gia hai 1nh AND Dng STL LD 000.03 AND 000.04 LD 000.05 AND 000.06 OR LD OUT 010.00 END

3.6. Lnh thi gian tr Dng STL LD 000.03 TIM 000 #010 LD TIM000 OUT 010.00 END

Ch : + Trong lnh (TIM 000 #010) lot s u ch

s hiu ca rle thi gian (rle thi gian s 0), lot s th hai ch thi gian t (10s) + Khi u vo 000.03 c gi tr 1 th b thi gian bt u tnh thi gian, khi 10s th b thi gian cho gi tr ra, tc u ra 010.00 c gi tr 1. 3.7. B m

LD 000.03 LD 000.00

57

CNT000 #005 LD CNT000 OUT010.00 END

Ch : + u vo th nht (000.03) l u vo m, mi khi u vo ny nhn gi tr 1

th b m m mt ln. + u vo th hai (000.00) l u vo reset b m, khi u vo ny nhn gi tr

1 th b m b reset v trng thi ban u. + Trong lnh (CNT 001 #0051 lot s u ch s hiu ca b m (b m s 1

lot s th hai ch s m t (5 s), khi u vo 000.03 t 5 ln gi tr 1 th b m cho gi tr ra, tc u ra 010.00 c gi tr 1.

58

CHNG 5: B IU KHIN PLC - S5

5.l. Cu to ca h PLC Step5

PLC Step 5 thuc h Simatic do hng Siemens sn xut. y l loi PLC hn hp va n khi va a khi. Cu to c bn ca loi PLC ny l mt n v c bn sau c th ghp thm cc module m rng v pha bn phi, c cc module m rng tiu chun S5-100U. Nhng module ngoi ny bao gm nhng n v chc nng m c th l hp li cho ph hp vi nhng nhim v k thut c th. 1. n v c bn

n v c bn ca PLC S5- 95U nh hnh 5.1.

Trong : 1. Ngn c quy, 2. Cng tc m in c quy, 3. Cng tt m ngun, 4. Bng cm v n bo cho u vo v ra logic, c: 16 u vo t I32.0 n

I33.7; 16 u ra t Q32.0 n Q33.7, 5. u ni ngun 24v cho khi c bn, 6. Giao din cho u vo b ngt IW59.0 n IW59.3 v u vo b m IW36

n IW38, 7. Giao din ni tip vi my lp trnh hoc my tnh, 8. Giao din tip nhn module nh ngoi, 9. Giao din cho u vo ra analog, 10. Cng tc chn ch RUN, STOP,

59

11. n bo ch STOP, 12. n bo ch RUN, 13. n bo li.

2. Cc module vo ra m rng Khi qu trnh t ng ho i hi s lng u v u ra nhiu hn s lng sn

c trn n v c bn hoc khi cn nhng chc nng c bit th c th m rng n v c bn bng cch g thm cc module ngoi. Ti a c th g thm 8 module vo ra qua 8 v tr c sn trn panen v pha phi. Thng Step 5 s dng cc module m rng:

+ Module vo, ra s duy tr, + Module vo, ra s khng duy tr ly t S5-100U, + Module vo, ra tng t khng duy tr ly t S5-100U, + Module thng tin khng duy tr CCP. * Quy c cc chn ca module m rng nh hnh 5.2. + Chn l: Dng ngun (L+), + Chn 2: m ngun (M), + Chn 4: Knh s 0, + Chn 3: Knh s 1, + Chn 6: Knh s 2, + Chn 5 : Knh s 3, + Chn 8: Knh s 4, + Chn 7: Knh s 5, + Chn 1 0 : Knh s 6 + Chn 9: Knh s 7.

5.2. a ch v gn a ch

Trong PLC cc a ch cn gi thng tin n hoc ly thng tin i u phi c a ch lin lc. a ch l con s hoc t hp cc con s i theo sau ch ci. Ch ci ch loi a ch, con s hoc t hp con s ch s hiu a ch.

Trong PLC c nhng b phn c gn a ch n nh b thi gian (T), b m (C) v c (F), ch cn mt trong 3 ch ci km theo mt s l , v d: T1, C32, F6...

Cc a ch u vo v u ra cng vi cc module chc nng c a ch phc, cch gn a ch ging nhau. Xt cch gn a ch cho cc u vo, ra.

C hai loi u vo ra: + u vo ra trn khi c bn (gn lin vi CPU), cc u vo ra ny c a ch

60

khng i, vi S5-95U l I32.0 n I33.7, Q32.0 n Q33.3, + u vo ra trn cc module m rng th a ch ph thuc vo v tr lp t ca

module trn panen. Ch lp module trn panen gi l khe (slot), cc khe u c nh s, khe s 0 ng lin vi n v c bn v c th tip tc. 1. a ch vo/ra trn module s

Khi lp module s vo ra ln mt khe no lp tc n c mang s hiu ca khe . Trn mi module th mi u vo ra l mt knh, cc knh u c nh s. a ch ca mi u vo ra l s ghp ca s hiu khe v knh, s hiu khe ng trc, s hiu knh ng sau, gia hai s c du chm. S hiu khe v knh nh hnh 5. 3 .

V d: a ch ca knh s 2 trn module cm vo khe s 0 l 0.2. Khe s: 0 1 2 3 ...

n v c bn

0 1 : 7

0 1 : 7

0 1 : 7

0 1 : 7

Hnh 5.3. S hiu khe v knh trn module s Mi u vo ra trn module s ch th hin c ti mt thi im mt trong hai

trng thi "1" hoc "0". Nh vy, mi knh ca module s ch c biu din bng mt bt s liu, v vy a ch ca knh trn module s cn c gi l a ch bt, mi module mang nhiu knh tc l cha nhiu bt, thng l 8 bt hay mt byte, v vy a ch khe cn gi l a ch byte.

Module s c th c lp trn bt k khe no trn panen ca PLC. 2. a ch vo ra trn module tng t

din t mt gi tr tng t phi cn nhiu bt. Trong PLC S5 ngi ta dng 16 bt (mt word). Cc lnh tng t c th c gn a ch byte hoc a ch word khi dng lnh np hoc truyn.

Ch c th lp module tng t vo khe 0 n 7. Mi khe c 4 knh, mi knh mang 2 a ch nh s l 64 + 65 (u khe 0) n 126 + 127 (cui khe 7) nh hnh 5.4.

Nh vy, mi knh mang a ch ring khng km theo a ch khe, c a ch knh l bit n nm khe no. V d: Mt module tng t lp vo khe s 2 trn knh s 0 mang a ch byte 80 v 81. Khe s: 0 1 2 3 4 5 6

n v c bn

64+65 66+67 68+69 70+ 71

72+73 74+75 76+77 78+79

80+81 82+83 84+85 86+87

88+89 90+91 92+93 94+95

96+97 98+99

100+l01 102+103

l04+l05 106+107 l08+l09 110+111

112+113 114+115 116+117 118+119

120+121 122+123 124+125 126+127

Hnh 5.4. a ch module tng t

61

Ch : Cc khe trng bao gi cng c trng thi tn hiu "0".

5.3. Vng i tng

TT Tn tham s Din gii Vng tham s 1 ACCUM 1 c quy 1 2 ACCUM2 c quy 2 3 BN Hng s byte -127 n 127 4 C B m - C nh

- Khng nh 0 n 7 8 n 127

5 CC0/CC1 M iu kin 1 v m iu kin 2 6 D S liu dng bt 0.0 n 255.15 7 DB Khi s liu 2 n 255 8 DL T (word) d liu tri 0 n 255 9 DR T (word) d liu phi 0 n 225 10 DW T (word) d liu 0 n 255 11 F C - C nh

- Khng nh 0.0 n 63.7 64.0 n 255.7

12 FB Khi hm 0 n 255 13 FW T (word) c - C nh

- Khng nh 0 n 62 64 n 254

14 FY T (word) byte - C nh - Khng nh

0 n 63 64 n 255

15 I u vo bt 0.0 n 127.7 16 IB u vo byte 0 n 127 17 Iw u vo t (word) 0 n 126 18 KB Hng s 1 byte 0 n 255 19 KC Hng s m 0 n 999 20 KF Hng s -32768 n 32677 21 KH Hng s dng c s 16 0000 n FFFF 22 KM Hng s bt dng byte Mi byte 16 bt 23 KS Hng s cho k t 2 k t ASCII 24 KT Hng s cho thi gian 0.0 dn 999.3 25 KY Hng s 0 n 255 cho mi byte 26 OB Khi t chc (khi c bit: 1, 3, 13, 21,

31, 34, 251) 0 n 255

27 PB Khi chng trnh 0 n 255 28 PB/PY m ngoi vi vo ra 0 n 127 29 PII B m u vo 30 PIQ B m u ra

62

TT Tn tham s Din gii Vng tham s 31 PW m ngoi vi dng t (word) 0 n 125 32 Q u ra bt 0.0 n 127.7 33 QB u ra dng byte 0 n 127 34 QW u ra dng t (word) 0 n 125 35 RS Vng s liu h thng 0 n 255 36 SB Khi dy 0 n 255 37 T B thi gian 0 n 127

5.4. Cu trc ca chng trnh S5

1. Cu trc chng trnh Cc chng trnh iu khin vi PLC S5 c th c vit dng n khi hoc

a khi. Chng trnh n khi Chng trnh n khi ch vit cho cc cng vic t ng n gin, cc lnh

c vit tun t trong mt khi. Khi vit chng trnh n khi ngi ta dng khi OBI. B PLC qut khi theo chng trnh, sau khi qut n lnh cui cng n quay tr li lnh u tin.

Chng trnh a khi (c cu trc) Khi nhim v t ng ho phc tp ngi ta chia chng trnh iu khin ra

thnh tng phn ring gi l khi. Chng trnh c th xp lng khi ny vo khi kia. Chng trnh ang thc hin khi ny c th dng lnh gi khi sang lm vic vi khi khc, sau khi kt thc cng vic khi mi n quay v thc hin tip chng trnh tm dng khi c.

Ngi lp trnh c th xp lng khi ny vo khi kia thnh lp, ti a l 16 lp Nu s lp vt qu gii hn th PLC t ng v trng thi ban u. 2. Khi v on (Block and Segment)

Cu trc mi khi gm c: + u khi gm tn khi, s hiu khi v xc nh chiu di khi. + Thn khi: Th hin ni dung khi v c chia thnh on (Segment) thc

hin tng cng on ca qu trnh t ng ho sn xut. Mi on li bao gm mt s dng lnh phc v vic gii bi ton logic. Kt qu ca php ton logic c gi vo RLO (Result of logic operation). Vic phn chia chng trnh thnh cc on cng nh hng n RLO. Khi bt u mt on mi th to ra mt gi tr RLO mi, khc vi gi tr RLO ca on trc.

+ Kt thc khi: Phn kt thc khi l lnh kt thc khi BE. Cc loi khi:

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* Khi t chc OB (Organisation Block): Khi t chc qun l chng trnh iu khin v t chc vic thc hin chng

trnh * Khi chng trnh PB (Program Block):

Khi chng trnh sp xp chng trnh iu khin theo chc nng hoc cc kha cnh k thut. * Khi dy SB (Sequence Block):

Khi dy l loi khi c bit c iu khin theo chng trnh dy v c x l nh khi chng trnh. * Khi chc nng FB (Function Block):

Khi chc nng l loi khi c bit dng lp trnh cc phn chng trnh iu khin ti din thng xuyn hoc c bit phc tp. C th gn tham s cho cc khi v chng c mt nhm lnh m rng. * Khi d liu DB (Dm Block) :

Khi d liu lu tr cc d liu cn thit cho vic x l chng trnh iu khin.

5.5. Bng lnh ca S5 - 95U

Cc lnh ca chng trnh S5 c chia thnh ba nhm l: 1. Nhm lnh c bn

Nhm lnh c bn gm nhng lnh s dng cho cc chc nng, thc hin trong cc khi t chc OB, khi chng trnh PB, khi dy SB v khi chc nng FB. Ngoi tr hai lnh s hc +F v -F ch c biu din bng phng php dy lnh STL, cn li tt c cc lnh c bn khc u c th c biu din bng c ba phng php l bng lnh STL, lu iu khin CSF v biu bc thang LAD. 2. Nhm lnh b tr

Nhm lnh b tr bao gm cc lnh s dng cho cc chc nng phc tp, v d nh cc lnh thay th, cc chc nng th nghim, cc lnh dch chuyn hoc chuyn i...

Cc lnh b tr dng trong khi chc nng v c biu din bng phng php bng lnh STL. Ch c rt t lnh c s dng phng php lu . 3. Nhm lnh h thng

Cc lnh h thng c php thm nhp trc lip vo h thng iu hnh v ch c th c biu din bng phng php bng lnh STL. Ch khi thc s am hiu v h thng mi nn s dng cc lnh h thng.

Din di ca cc lnh xem phn "Bng lnh" ph lc 2.

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5.6. C php mt s lnh c bn ca S5

1. Nhm lnh logic c bn Khi thc hin lnh u tin ca mt lot php ton logic th ni dung ca i

tng lnh c ly vo s c np ngay vo RLO (kt qu ca php ton logic) m khng cn thc hin php ton.

i tng ca cc lnh logic l: I, Q, F, T, C 1.1 Lnh A

Lp trnh dng STL (c th lu trnh dng LAD v kim tra li dng STL).

+ n Enter tr v mn hnh Output. + n Shift-F5 Xem dng LAD v CSF, dng LAD nh hnh 5.6. + n Shift-F7 ct chng trnh v chng trnh sang PLC, chn yes xc

nhn vic chng trnh ln chng trnh c trong PLC (khi ct th PLC phi ch STOP).

+ Bt cng tc ca CPU v ch RUN chy chng trnh. 1.2. Lnh AN

Lp trnh dng STL A I 32.0 AN I 32.1 A I 32.2 = Q 32.0

BE 1.3. Lnh O

Lp trnh dng STL O I 32.0 O I 32.1 O I 32.2 = Q 32.0 BE

1.4. Lnh ON Lp trnh dng STL O I 32.0

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ON I 32.1 O I 32.2 = Q 32.0 BE

1.5. Lnh O gia hai lnh A Lp trnh dng STL A I 32.0 A I 32.1 O A I 32.2 A I 32.3 = Q 32.0 BE

1.6. Lnh "(" v lnh ")" Lp trnh dng STL O I 32.0 O A I 32.1 A( O I 32.2 O I 32.3 = Q 32.0 BE

2. Nhm lnh set v reset Cc lnh set v reset lu gi hoc xo b kt qu ca php ton logic c

hnh thnh trong b x l. i tng ca cc lnh ny l I, Q, F.

V d l: A I 32.0 S Q 32.0 A I 32.1 R Q 32.0 NOP0 Khi u vo I32.0 c th u ra Q32.0 c v c gi li cho d I32.0 mt, ch

khi I32.l c th li xo nh lm Q32.0 v khng.

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Lnh NOP 0 l lnh gi ch cho phng php LAD. V c u ra Q cha dng, mun phng php LAD v c hnh th phi a lnh NOP 0 vo. V d 2:

A I 32.0 R F 17 A I 32.1 S F 17 A F 17 = Q 32.0 y l v d v lnh st tri, v khi I32.0 c trng thi 1 th n s xo trng thi

tn hiu trn c F17 v "0" cho n khi I32.1 c trng thi 1 th n s t trng thi 1 cho c F17 sau khng ph thuc I32.0 na. Khi c nhn trng thi 1 th s gn cho u ra Q32.0 trng thi 1. Khi c I32.0 v I32.l cng c trng thi 1 th c s c trng thi 1 v lnh st sau, gi l u tin st. 3. Nhm lnh np v truyn

Lnh np v truyn trao i thng tin gia cc vng i tng lnh khc nhau. Lnh np v truyn chun b gi tr thi gian v gi tr m cho cc lnh thi

gian v lnh m, np hng s phc v vic x l chng trnh. Lng thng tin c np v truyn thng qua hai thanh ghi tch lu ACCU1 v

ACCU2. Thanh ghi tch lu l thanh ghi c bit trong PLC dng lu tr tm thi cc thng tin. Mi thanh ghi c di 16 bt.

C th np hoc truyn cc i tng theo byte hoc t (word). trao i theo byte, thng tin lu tr trong byte phi tc l byte thp ca thanh ghi, s bt cn tha (ngoi 8 bt) c t khng. C th dng cc lnh khc nhau x l cc thng tin trong hai thanh ghi. Cc lnh thuc nhm ny l:

Lnh np L: Ni dung ca i tng (n v byte) c chp vo ACCU1 khng ph thuc vo RLO v RLO cng khng b nh hng. Ni dung trc ca ACCU1 c chuyn dch sang ACCU2, ni dung c ca ACCU2 s b mt.

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V d: Np lin tip IB7 v IB8 t vng m PII vo thanh ghi tch lu, c s np nh hnh 5.14.

Lnh truyn T: Ni dung ca ACCU1 c gn cho i tng lnh khng ph thuc RLO v RLO cng khng b nh hng. Khi truyn th thng tin t ACCU1 c chp vo vng nh c a ch ho (v d vng m u ra PIQ). Ni dung ca ACCU1 khng b mt. Gi tr trc ca vng m u ra PIQ b mt. M t lnh nh hnh 5.15.

Lnh LD: S m v s thi gian c np vo ACCU1 dng m BCD, khng ph thuc vo RLO v RLO cng khng b nh hng.

Hnh 5.15. Lnh truyn

i tng ca cc lnh ny l: + Lnh L: IB, IW, QB, QW, FY, FW, DR, DL, DW, PB/PY, PW, T, C, KM, KH,

KF, KY, KB, KS, KT, KC. + Lnh T: IB, IW, QB, QW, FY, FW, DR, DL, DW, PB/PY, PW. + Lnh LD: T, C.

4. Nhm lnh thi gian Chng trnh iu khin s dng cc lnh thi gian theo di, kim sot v

qun l cc hot ng c lin quan n thi gian. 4.1. Np gi tr thi gian

Khi mt b thi gian c khi pht th ni dung trong ACCU1 (dng t 16 bt) c dng lm gi tr tnh thi gian. Do , mun dng cc lnh thi gian phi np gi tr thi gian cn t vo ACCU1 trc khi b thi gian hot ng.

C th np cc kiu d liu sau dng cho cc lnh thi gian: + KT: gi tr thi gian hng s. + DW: t (word) d liu. + IW: t (word) u vo. + QW: t (word) u ra. + FW: t (word) c. Tr loi KT cc loi cn li phi dng m BCD.

Np thi gian hng s: L KT 40.2 Trong lnh c: KT ch r l hng s.

S 40: h s (c th gn t 0 n 999).

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S 2: l m, c 4 m: 0 tng ng 0,01s; 1 tng ng 0,1s; 2 tng ng 1s; 3 tng ng 10s.

Vi s trn th thi gian c tnh l t = 40 x 1s = 40s . M cng nh th gi tr thi gian cng chnh xc, v vy nn dng m nh.

Np thi gian di dng u vo, u ra, hoc t d liu: V d mun np mt gi tr thi gian t mt t d liu DW2 vo ACCU1, vit lnh sau: L DW2 Nh vy, trc khi thc hin lnh ny th gi tr thi gian c lu sn trong

t d liu DW2 di dng m BCD. V d trong DW2 c cc s nh hnh 5.16:

M thi gian cng c s dng nh trn.

t = 638 x 1s = 638s . Vy, trc khi dng lnh np trn phi dng chng trnh iu khin vit gi

tr thi gian vo t d liu DW2. V d vit gi tr thi gian 27s vo t d liu DW2 trong khi DB3 ri sau np vo ACCU1 nh sau:

C DB3 L KT 270. 1 T DW2 L DW2

4.2. c gi tr thi gian hin hnh C th dng hai lnh L v LD a gi tr thi gian hin hnh ca b thi gian

T vo ACCU1 x l. L Tl % c gi tr thi gian dng nh phn. LD Tl % c gi tr thi gian dng BCD.

Ch : Lnh L v T i vi T v C th bao gi cng c gi tr nh phn cn i vi cc i tng khc th cng c th c gi tr nh phn hoc dng BCD tu theo trng hp c th. 4.3. Cc lnh

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1. B thi gian xung SP B thi gian c khi pht ln 1 ti si ln ca RLO khi RLO l 1 th b thi

gian vn duy tr trng thi 1 cho n khi t gi tr t mi xung. Nhng khi RLO v khng th b thi gian v khng ngay.

Lp trnh dng STL (c th lp trnh dng LAD v kim tra li dng STL). A I 32.0 L KT 500.0 NOP 0 NOP 0 NOP 0 A T 1 = Q 32.0 BE

Hnh 5.17. Gin thi gian v dng LAD lnh SP

Khi lp trnh cn ba chn R, BI v DE cha s dng phi dng lnh NOP gi ch. Chn R l chn xo gi tr thi gian hin hnh, chn BI l chn ly gi tr thi gian hin thi dng nh phn, chn DE l chn ly gi tr thi gian hin thi dng m BCD, c th dng lnh L hoc LD c cc gi tr thi gian. 2. B thi gian m rng SE

B thi gian xung m rng SE c khi pht ln 1 ti sn ln ca RLO sau khng ph thuc RLO na cho n khi thi gian t mi v khng.

Lp trnh dng STL C DB 3 L KT 500.0 T IW 16 A I 33.0 L IW 16 SE T 2 NOP0 NOP0

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NOP0 A T2 = Q 33.0 BE

3. B thi gian bt u tr SD Thi gian bt u chm hn so vi sn ln ca RLO mt khong bng thi gian

t trong lnh. Khi RLO v khng th b thi gian cng b t ngay v khng. Lp trnh dng STL. C DB 3 L KT 50.1 T FW 16 A I 33.0 L F W16 NOP0 NOP0 NOP0 = Q 33.0 BE

4. B thi gian bt u tr lu tr SS Thi gian bt u chm hn so vi

sn ln ca RLO mt khong thi gian bng thi gian t trong lnh v sau khng ph thuc RLO na. N ch v khng khi c lnh xo R.

A I 33.0 L KT 500.0 SS T 4 A I 32.0 R T 4 NOP 0 NOP 0 A T 4 = Q 32.0 BE

5. B thi gian tt tr SF

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B thi gian ln 1 ti sn ln ca RLO. Khi RLO v khng th b thi gian tip tc duy tr trng thi mt khong thi gian na bng khong t trong lnh ri mi v khng. xo thi gian dng lnh R, khi c lnh R t 0 ln 1 th b thi gian c t v khng v trng thi tn hiu vn gi 0 cho n khi b thi gian c khi pht li.

A I 33.0 L KT 50.1

SF T 4 NOP 0 NOP 0 NOP 0 A T 4

= Q 33.0 BE

5. Nhm lnh m 5.1. Np gi tr m

Cng nh b thi gian khi mt b m c khi pht th ni dung trong ACCU1 (dng t 16 bt) c dng lm gi tr m. Do , mun dng cc lnh m phi np gi tr m vo ACCU1 trc khi b m hot ng.

C cc kiu d liu sau dng cho cc lnh m: + KC: gi tr hng s. + DW: t (word) d liu. + IW: t (word) u vo. + QW: t (word) u ra. + FW: t (word) c. Tr loi KC cc loi cn li phi dng m BCD.

Np gi tr m hng s. L KC 38 S m t 0 n 999

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Np s m di dng u vo, u ra, hoc t d liu: V d mun np mt gi tr m t mt t d liu DW2 vo ACCU1, vit lnh sau: L DW2 Nh vy, trc khi thc hin lnh ny th gi tr m c lu sn trong t d

liu DW2 di dng m BCD. V d trong DW2 c cc s nh hnh 5.22:

Vi lnh trn th s 638 c np vo DW2.

i tng ca lnh: C hai lnh m ch c mt i tng l b m C vi cc s hiu tu thuc loi PLC.

5.2. Chun b thc hin cc lnh m + t b m: Sau khi np gi tr m dng lnh S cho b m lm vic. + Xo b m: Khi m ti mt gi tr no dng lnh R xo, tc l

ngng m v a gi tr m v khng, nu khng dng lnh ny khi m gi tr t b m gi nguyn trng thi khng v khng.

+ Qut b m: Dng lnh logic boole qut b m (v d lnh A). Nu b m cha v khng th kt qu qut c trng thi 1 .

+ Xut ra trng thi b m hin hnh: C th dng lnh L v LD a trng thi b m hin hnh vo ACCU1 x l sau ny, lnh L dng cho s nh phn, lnh LD dng cho s BCD.