c5.pdf

http://www.ebook.edu.vn Bai giang: "ieu khien ien- kh nen"

Chng 5: ieu khien bang ien - kh nen. 72

CHNG 5: IEU KHIEN BANG IEN - KH NEN. 5.1. CAC PHAN T IEN - KH NEN: He thong lap rap ien - kh nen c bieu dien mot cach tong quat theo hnh 5.1. Mach ien ieu khien thong thng la dong ien mot chieu.

Nut an

Bo nguon

U =230V50Hz

U =24VDC

vao

ra

Bo phan phoi ien

Tiep iem

Nam cham ienR - le

Phan t ieu khien(van ao chieu)

Mach ien ieu khien C cau chap hanh

Hnh 5.1: He thong ieu khien ien kh nen. 5.1.1. Van ao chieu ieu khien bang nam cham ien: a/ Ky hieu: Van ao chieu ieu khien bang nam cham ien ket hp vi kh nen co the ieu khien trc tiep hai au nong van hoac gian tiep qua van phu tr. Hnh 5.2 bieu dien mot so ky hieu loai ieu khien.

Van ao chieu ieu khien gian tiep bang nam cham ien va kh nen ca hai pha

Van ao chieu ieu khien gian tiep bang nam cham ien va ap thap ca hai pha

Van ao chieu ieu khien trc tiep bang nam cham ien ca hai pha

Van ao chieu ieu khien trc tiep bang nam cham ien va lo xo

Hnh 5.2: Ky hieu cac loai ieu khien.

b/ ieu khien trc tiep: Hnh 5.3 bieu dien cau tao va ky hieu cua van 2/2 ieu khien trc tiep bang nam cham ien.

P

Ky hieuA

P

A

Hnh 5.3: Van 2/2 ieu khien trc tiep bang nam cham ien.



Cau tao va ky hieu cua van ao chieu 3/2 ieu khien trc tiep bang nam cham ien c bieu dien trong hnh 5.4.

A P

Ky hieu

R

A

P R

Hnh 5.4: Van 3/2 ieu khien trc tiep bang lo xo.

5.1.2. ieu khien gian tiep: Nguyen ly hoat ong cua van ao chieu 3/2 ieu khien gian tiep bang nam cham ien va kh nen c bieu dien trong hnh 5.5 gom hai van: van chnh va van phu tr. Khi van v tr khong ca noi vi nguon P se noi vi nhanh b, e van chnh nam v tr b. Cau tao cua van ao chieu 3/2 ieu khien gian tiep bang nam cham ien c bieu dien hnh 5.5.

R

A

Van chnh

Van phu tr

Cuon dayLoi sat

Lo xo

Pt tong phu

Nong vanP

A

P R

Ky hieu

Hnh 5.5: Cau tao va ky hieu van ao chieu 3/2 ieu khien gian tiep bang nam cham

ien va kh nen. d/ Mot so van ao chieu:

Van ao chieu 4/2 ieu khien gan tiepbang nam cham ien va kh nen

R P

BA



R P S

BAVan ao chieu 5/2 ieu khien gan tiepbang nam cham ien va kh nen

Hnh 5.6: Cau tao van ao chieu ieu khien gian tiep bang nam cham va kh nen. 5.2. CAC PHAN T IEN: 5.2.1. Cong tac: Trong ky thuat ieu khien, cong tac, nut an thuoc cac phan t a tn hieu. Hnh 5.7 gii thieu hai loai cong tac thong dung: cong tac ong m va cong tac chuyen mach quay.

Ky hieu

Hnh 5.7: Ky hieu cong tac.

5.2.2. Nut an: Nut an ong m. Hnh 5.8 khi cha co tac ong th cha co dong ien chay qua, khi tac ong th co dong ien i qua. Nut an chuyen mach, s o cau tao va ky hieu trnh bay trong hnh ve.

Ky hieu

Hnh 5.8: Nut nhan va ky hieu.

5.2.3. R le: Trong ky thuat ieu khien, r le c s dung nh la phan t x ly tn hieu. Co nhieu loai rle khac nhau, tuy theo cong dung. Nguyen tac hoat ong cua rle la t trng cuon day. Trong qua trnh ong m se co hien tng t cam. - R le ong mach: Nguyen ly hoat ong cua rle ong mach c bieu dien hnh 5.9. Khi dong ien vao cuon day cam ng, xuat hien lc t trng hut loi sat, tren o co lap cac tiep iem. Cac tiep iem co the la cac tiep iem chnh e ong m mach chnh va cac tiep



iem phu e ong m mach ieu khien. Rle ong mach ng dung cho mach co cong suat ln t 1 kW 500kW.

Ky hieu

K

Hnh 5.9: Ky hieu cua rle ong mach.

- Rle ieu khien: Nguyen ly hoat ong cua rle ieu khien cung tng t nh rle ong mach, no ch khac rle ong mach cho la rle ieu khien ong m cho mach co cong suat nho va thi gian ong, m cac tiep iem rat nho (t 1ms en 10ms).

Tiep iem

on bay

Ky hieu

A

K

A

1

2

3

4

1

2K

241

3

Hnh 5.10: R le ieu khien.

- Rle thi gian tac ong muon: Nguyen ly hoat ong cua rle tac ong muon tng t nh rle thi gian tac ong muon cua phan t kh nen, iot tng ng nh van mot chieu, tu ien nh bnh trch cha, bien tr R1 nh van tiet lu. ong thi tu ien co nhiem vu giam ien ap qua tai trong qua trnh ngat.

S1+

-

R2

D

C KR1 K1 K

Ky hieu

Hnh 5.11: Rle thi gian tac ong muon.

- Rle thi gian nha muon: Nguyen ly hoat ong cua rle thi gian nha muon tng t nh rle thi gian nha muon cua phan t kh nen, iot tng ng nh van mot chieu, tu ien nh bnh



trch cha, bien tr R1 nh van tiet lu. ong thi tu ien co nhiem vu lam giam ien ap qua tai trong qua trnh ngat.

S1+

-

R2

D

C KR1 K1 K

Ky hieu

Hnh 5.12: Rle thi gian nha muon.

- Cong tac hanh trnh ien - c: Nguyen ly hoat ong cua cong tac hanh trnh ien c c bieu dien trong hnh 5.15. khi con lan cham c hanh trnh th tiep iem 1 noi vi 4.

Ky hieu

Hnh 5.13: Cong tac hanh trnh ien c.

Can phan biet cac trng hp cong tac thng ong va thng m khi lap cong tac hanh trnh ien - c trong mach. 5.2.4. Cong tac hanh trnh nam cham: Cong tac hanh trnh nam cham thuoc loai cong tac hanh trnh khong tiep xuc. Nguyen ly hoat ong, ky hieu c bieu dien hnh 5.16.

Hop cong tacXy - lanh khong t tnh hoa

Nam cham vnh cu Can pt - tongPt - tong

Hnh 5.14: Cong tac hanh trnh nam cham.

5.2.5. Cam bien cam ng t: Nguyen ly hoat ong cua cam bien cam ng t bieu dien hnh 5.18. Bo tao dao ong se phat ra tan so cao. Khi co vat can bang kim loai nam trong vung t trng, trong kim loai o se hnh thanh dong ien xoay. Nh vay, nang lng cua bo dao ong se giam. Dong ien xoay se tang, khi vat can cang gan cuon cam ng. Qua o bien o dao ong cua bo dao ong se giam. Qua bo so, tn hieu se c khuech ai.



- Cam bien ien dung: Nguyen ly hoat ong cua cam bien ien dung bieu dien trong hnh 5.19. Bo tao dao ong se phat ra tan so cao. Khi co vat can bang kim loai hoac phi kim loai nam trong vung ng sc cua ien trng, ien dung tu ien thay oi. Nh vay, tan so rieng cua bo dao ong thay oi. Qua bo so va bo nan dong tn hieu c khuech ai. - Cam bien quang: Nguyen tac hoat ong cua cam bien quang gom hai phan: - Bo phan phat. - Bo phan nhan. Bo phan phat se phat i tia hong ngoai bang iot phat quang, khi gap vat chan, tia hong ngoai se phan hoi lai vao bo phan nhan. Nh vay, bo phan nhan, tia hong ngoai phan hoi se c x ly trong mach va cho tn hieu ra sau khi khuech ai.

en phat quang May phat song

Transistor quang Bo loc Bo khuech ai

Tn hieu ra

Vat chan

Bo phan nhan

Bo phan phat

Hnh 5.15: Cam bien quang.

5.2.6. Bieu dien ieu khien tiep iem ien: ieu khien tiep iem c bieu dien vi s o mach trang thai khong ong. - S o dong bieu dien lien quan vi nhau:

R - le bao veR - le ieu khien

en bao

Bo ngat nh v

M

ong c

+-

K10K1

H1

L1L2L3N

Nguon ieu khien(24 V DC)

H5.16: S o bieu dien cac mach ien lien quan vi nhau.



Vi bo ngat S1 r - le K1 qua bao ve K10 noi mach ien xoay chieu vao ong c M1. en bao H11 cua bo ngat nh v sang neu ong c c noi mang va tat neu ong c ng yen. Tn hieu thay oi khi bo ngat nh v khong con b tac ong. - S o bieu dien tach: s o nay moi thiet b ien c bieu dien bang mot oan dong. Cac oan mach can c anh so va ve t tren xuong di va ke ben nhau. Trong s o nay, ngi ta chia ra hai loai mach c ban trong ieu khien. Mac ieu khien bao gom cac thiet b a tn hieu, thiet b ieu khien .v.v Mach ong lc bieu dien s ket noi cua nguon ong lc vi c cau chap hanh.

K

+

-

1K1

K1 K10H1

S1

M

L1L2L3N

Mach ong lc (380 V AC, 3 )Mach bao ve (220 V AC)Mach ieu khien 24 V DC

K10

H5.17: S o dong bieu dien tach.

5.2.7. Mach c s ieu khien tiep iem ien: - Truyen tn hieu vi mot r - le hoac bao ve, ngi ta co the truyen tn hieu mach t oan mach nay sang oan mach khac ma khong can noi ien gia chung. Muc ch la mach ieu khien ch can mot ien ap nho mot chieu hoac xoay chieu, nh tac ong cua r - le co the ieu khien c nhieu muc ch khac nhau nh: * Khuech ai: R - le K1 ch can mot cong suat ien rat nho e ong ngat. Tiep iem K1 cua r - le co the ong ngat mot cong suat ln gap nhieu lan. * Nhan len: R - le co rat nhieu tiep iem, ngi ta co the dung cac tiep iem nay e ong ngat nhieu mach ien (nh he thong en bao hieu, bm nc lam nguoi .v.v). Nh vay, vi mot tn hieu co the ieu khien c rat nhieu mach. * ao ngc: Vi bo ngat S1, cac thiet b co the c ong. en bao H1 ch can sang khi ong c hoac may cong tac ng yen va tat khi a ong mach. Viec ao tn hieu nay co c nh mot bo m tn hieu cua r - le K1 (tiep iem thng m). R - le am nhiem ca viec ao tn hieu. * Lien ket:

oi vi lien ket AND, cac tiep iem c au noi tiep. R - le K1 ch hoat ong vi ieu kien bo ngat nh v S1 va S2 c tac ong. Lien he nay c bieu dien bang ham so mach, ky hieu K1 = S1 S2.

oi vi lien ket OR cac tiep iem c au song song. R le K1 hoat ong vi ieu kien ch can mot trong hai bo ngat nh v S1 va S2 c tac ong. Lien he nay c bieu dien bang ham so mach, ky hieu K1 = S1 S2.



oi vi lien ket NOT cac tiep iem c au song song. R - le K1 hoat ong vi ieu kien bo ngat nh v S1 khong tac ong. Trng hp S1 c tac ong r - le K1 ieu khien tiep iem thng ong m ra, mach ong lc b ngat. Lien he nay c bieu dien bang ham so mach, ky hieu K1 = S1.

Lien ket nay thng hay gap trong trng hp mach ieu khien ong c ien xoay chieu 3 pha thay oi chieu quay trong qua trnh lam viec. Th du: K1 ieu khien cho ong c quay phai, K2 ieu khien cho ong c quay trai. e ong ngat K1 va K2 co the dung tiep iem co nh v nh c hoc, hoac tiep iem thng m K1 ket hp vi lien ket NOT e khoa tiep iem K2 va ngc lai khi muon oi chieu quay. +

-K1

S1

Lien ket AND

S2

S1 S1

K1 K1

S1

K2

+

-

+

-Lien ket OR Lien ket NOT

K2

S2

K1

Hnh 5.18: Cac loai lien ket trong mach ien.

* Duy tr trang thai mach: Mot trang thai mach co the c duy tr nh mot tiep iem t gi. mach t

duy tr co khoa K1 trong oan mach r - le K1 co cha mot tiep iem thng m cua r - le o c au song song vi khoa K1. Neu nut ong S1 tac ong ngat, R - le K1 c kch thch va khoa K1 ong dong song song vi S1. Nh o r le c t gi trang thai kch thch, ca khi S1 tr ve v tr m. Nut ngat S2 lam cho K1 mat dong, duy tr b xoa. Nut ngat S2 trc nhanh t duy tr se ngat r - le K1 trong moi trng hp, ke ca nut ong S1 c tac ong.

+

-

K (Tiep iem duy tr)1

K1

S (Ngat)2

S (Khi ong)1S (Ngat)3

Hnh 5.19: Mach duy tr.



5.3. THIET KE MACH IEU KHIEN IEN KH NEN: 5.3.1. Nguyen tac thiet ke: S o mach ien - kh nen gom co hai phan: - S o mach ien ieu khien. - S o mach kh nen. Cac phan t ien a c trnh bay phan tren. Sau ay la ky hieu cac phan t ien: - Tiep iem:

Thng m Thng ong Chuyen mach ong cham M cham Nha cham

- Nut an:

Thng m Thng ong Chuyen mach Chuyen mach 4 au day - Rle:

Ky hieu chung Tac ong muon Nha muon

- Cong tac hanh trnh:

Cong tac hanh trnh ien c(loai tiep xuc)

Cong tac hanh trnh nam cham(loai khong tiep xuc)

- Cam bien:

Cam ng t

Fe

ien dung Quang 5.3.2. Mach ieu khien ien - kh nen vi 1 xy - lanh: a/ Mach ieu khien vi tiep iem t duy tr: C s e thiet ke mach ieu khien ien - kh nen la bieu o trang thai.



Xy - lanh 1.0

4321

+

-

RPS

BA

Xy - lanh 1.0

Y a b5

Hnh 5.20: Bieu o trang thai va s o mach kh nen.

S o s o mach ien ieu khien c bieu dien trong hnh 5.19. Khi tac ong vao nut an S2, rle K2 co ien, cac tiep iem tng ng cua rle K2 se ong, o la tiep iem K2 nhanh th ba va K2 nhanh th nam. Khi nha nut an S2, nh tiep iem duy tr K2 nhanh th ba, rle K2 van co ien va tiep iem K2 nhanh th nam - tiep iem ong e dong ien qua cuon cam ng cua van ao chieu, xylanh i ti..

Khi tac ong vao nut an vao nut an S1 dong ien trong nhanh hai mat, rle K2 mat ien, cac tiep iem tng ng m ra va xylanh se lui ve.

Xy - lanh lui ve

Xy - lanh i ti Tiep iemt duy tr

K+

-

2

K2

K2 Y5H3

S2

S1

1 2 3 4 5

Hnh 5.21: Mach ieu khien vi tiep iem t duy tr.

b/ Mach ieu khien vi rle thi gian tac ong muon: Bieu o trang thai, s o mach kh nen c trnh bay hnh 5.22. S o mach ieu khien vi phan t t duy tr va rle thi gian tac ong muon. Sau thi gian t1 cong tac hanh trnh ien - c S2 ong (v tr cuoi hanh trnh), th rle thi gian tac ong muon K2 mi co ien.

Xy - lanh 1.04321+

-

RPS

BA

Xy - lanh 1.0

Y a b6a

0

1

01

01

0

Nut an S

R le thi gian tac ong muon K

Cong tac hanh trnh ien c S

4a

2

2

1.1

S 2

Hnh 5.22: Bieu o trang thai va mach kh nen.



Xy - lanh lui ve

Xy - lanh i ti Tiep iemt duy tr

K+

-

4

K4

K4 Y6aH5

S4a

S4

1 2 3 4 5

K2 H3

S2

76

Hnh 5.23: Mach ieu khien t duy tr vi rle thi gian tac ong muon.

c/ Mach ieu khien ket hp vi thuy lc (dau ep): Quy trnh gia cong cua may khoan c bieu dien hnh 5.23. Trong trng hp may khong hoat ong, au khoan phai nam v tr pha tren, cho nen chon van ao chieu bang nam cham ien va lo xo.

Chc nang

P

Y

a

b

1

au khoan i ti (nhanh)

au khoan lui ve (nhanh)

Khoan (cham)

a b2

7.0S

7.1SS 7.2

Y Y21

1 0

11

00

S

7.2SS 7.1

7.0

Bieu o trang thai Xy - lanh thuy lc giam chan

Hnh 5.24: Quy trnh gia cong cua may khoan.

K

+

-

5K3

K3 Y2

K2

K1

1 3

K1

S1

12

S0

S7.4

S3

S2

K2

K4

K4

K4

K2

K1

5

K5

K3S7.0

K5

K5

K4

7

K1

S7.1

K6

S7.2

K5

K6

K5

Y1

K4

102 4 6 8 119

Hnh 5.25: S o mach ien ieu khien qui trnh khoan.

d/ Mach ieu khien ien - kh nen vi 2 xy lanh: - Mach ieu khien theo nhp:



Quy trnh mach ieu khien theo nhp vi 2 xy lanh bieu dien tren hnh 5.25. Khi tac ong vao nut an S5, cac xy lanh se thc hien theo quy trnh e ra.

Y1

S S S

Y2

S1 2 3 4

Xy - lanh

Cong tac hanh trnh

Nam cham ien

A+ B+ A-B-

S S SS5 2 34

KT

S1Y Y 001 2

A

B

SS

SS

1

2

34

Hnh 5.26: Qui trnh ieu khien 2 xy - lanh.

Moi nhp eu co mach t duy tr. Sau khi an nut khi ong S5. Lan lt nhp 1 cho en cac nhp tiep theo se ong mach. Nhp cuoi cung tac ong cho quy trnh tr ve v tr ban au.

+

-Y2

K4

K4

K3

Y1

K1K2

K2

K1

K1

K5

K3

K3

K2

SET

K5

S1

S5 S2 S4 S3

K1

K4 K4

K2

K3

Hnh 5.27: S o mach ien ieu khien quy trnh khoan.

Neu ta chon van ao chieu 4/2 xung, ca hai pha tac ong bang nam cham ien, s o mach ieu khien ien bieu dien tren hnh 5.27. Mac dau moi nhp co mach t duy tr, nhng neu nhp tiep theo c thc hien, khi nhp trc o phai c xoa.



Y1

S S S

Y3

S1 2 3 4Xy - lanh

Cong tac hanh trnh

Nam cham ien

A+ B+ A-B-

S S SS5 2 34

KT

S1

Y Y1 3Y2 Y4 Y Y4 2

+

-Y3

K4

K4

K5

Y1

K1

K2

K2

K1

K1

K2

K3

K3

K4

K5

S1

K5K1 K2

K3

K4K2

S5

K1

S2 S4 S3SET

K5

K3

Y4

K3

Y2

K4

Chua

n b

Xoa

Hnh 5.28: Quy trnh ieu khien vi van ao chieu xung 4/2. - Mach ieu khien vi chon che o lam viec: Quy trnh gia cong cung tng t vi v du tren. ieu kien yeu cau tiep theo la xy - lanh B chuyen ong, khi thoa man ieu kien la ap suat trong xy - lanh A at c gia tr cho phep. Nh vay ap suat trong xy - lanh A (xy - lanh) kep chi tiet c kiem soat bang rle ap suat - ien.

Y1

S S S

Y3

S2 4 8 10

Y2

+

- K8K4K 2 K 6 K15

S2 S15

K17

S4 S6 S8

A (Kep chi tiet) B (au khoan)

S2 S2

S8 S8

S10

S4

S6

R - le ap suat

K10

S10

K17

K15

K20

K15

K8S20Thao

K17

K28

K22

S22Kep

K24

K15

S24aTien

K17K8

K24

S24Lui

K20K4K6

K 28

K 28

K 17

K24K17

K10

K 2

A B A BA thong bao

(sau khi a lui ve)Chon che o

lam viec

Hnh 5.29: Quy trnh gia cong vi chon che o lam viec va s o mach ien ieu khien.



Y2Y1

K22 K20

Y3

K24

A B

ThaoKep Tien/lui

5.3.3. Bo ieu khien theo tang: Nguyen tac thiet ke mach ieu khien theo tang la chia cac bc thc hien co cung chc nang thanh tng tang rieng. Phan t c ban cua ieu khien theo tang la phan t nh - R - le.

- Mach ieu khien cho 2 tang: +

-

K1

K1

Sc

S

e 2

K1 K1

T1 T2

Hnh 5.30: Mach ieu khien 2 tang.

- Mach ieu khien cho 3 tang: +

-

K1

K1

Sc

S

e 3

K1

K2

e 2K2 K2 K2

K1

T2 T1 T3




Th du 1: Mach ieu khien 2 tang:

+

-Y3

K1

K1

a 0

S

b1

K1 K1

Tang 1 Tang 2

A

a b

B

a b

a a bb0 1 0 1

Y1 Y2 Y3 Y4

Y1

a1

Y4 Y2

b0

Aa

a

b

bB

1

01

0


Th du 2: Mach ieu khien 3 tang:

+

-

K1

K1

a 0

S

c1

K1

K2

b1K2 K2

K1

Tang 1

A

a b

B

a b

a a bb0 1 0 1

Y1 Y2 Y3 Y4

C

a b

cc 0 1

Y5 Y6

Aa

a

b

bB

c

cC

Y1

a1

Y3

K2

Y4

b0

Y5 Y6

c 0

Y2

Tang 2 Tang 3

1

01

01

0


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