tailieuPLC S7 300

8/9/2019 tailieuPLC S7 300

1/94

http://www.ebook.edu.vnLp trnh vi SPS S7-300 7

Chng1.H thng iu khin.

1.1.Khi nim h thng iu khin:

Trong cng nghip yu cu t ng ho ngy cng tng, i hi k thut iu

khin phi p ng c nhng yu cu . gii quyt c nhim v iu

khin ngi ta c th thc hin bng hai cch: thc hin bng Rle, khi ng t

... hoc thc hin bng chng trnh nh. H iu khin bng Rle v h iu

khin bng lp trnh c nh khc nhau phn x l: thay v dng Rle, tip

im v dy ni trong phng php lp trnh c nh chng c thay bng cch

mch in t. Nh vy thit b PLC lm nhim v thay th phn mch in iu

khin trong khu x l s liu. Nhim v ca s mch iu khin s c xc

nh bng mt s hu hn cc bc thc hin xc nh gi l "chng trnh".Chng trnh ny m t cc bc thc hin gi l tin trnh iu khin, tin trnh

ny c lu vo b nh nn c gi l "iu khin lp trnh c nh". Trn c

s khc nhau ca khu x l s liu ta c th biu din hai h iu khin nh

sau:

Cc bc thit lp s iu khin bng Rle:

Hnh 1-1:lu iu khin dng Rle

Xc nh nhim v iu khin

S mch in

Chn phn t mch in

Dy ni lin kt cc phn t

Kim tra chc nng


2/94

http://www.ebook.edu.vnLp trnh vi SPS S7-3008

Cc bc thit lp s iu khin bng PLC:

Hnh 1-2: Lu iu khin bng PLC

Khi thay i nhim v iu khin ngi ta cn thay i mch iu khinbng cch lp li mch, thay i phn t mi i vi h thng iu khin bng

Rle in. Trong khi khi thay i nhim v iu khin ta ch cn thay i

chng trnh son tho i vi h iu khin bng lp trnh c nh.

S khc nhau gia h iu khin bng Rle in v lp trnh c nh c th

minh ho bng mt v d sau:

iu khin h thng 3 my bm nc qua 3 khi ng t K1, K2, K3. Trnh

t iu khin nh sau: Cc my bm hot ng tun t ngha l K1 ng trc

tip n l K2 ri cui cng l K3 ng. thc hin nhim v theo yu cu trn mch iu khin ta thit k nh sau:

Trong cc nt n S1, S2, S3, S4 l cc phn t nhp tn hiu.

Cc tip im K1, K2, K3 v cc mi lin kt l cc phn x l.

Cc khi ng t K1, K2, K3 l kt qu x l.

Xc nh nhim v iu khin

Thit k thut gii

San tho chng trnh

Kim tra chc nng


3/94


Hnh 1-3:S iu khin

Nu ta thay bng thit b iu khin PLC ta c th m t nh sau:

-Tn hiu vo: S1, S2, S3, S4 vn gi nguyn.

-Tn hiu ra: K1, K2, K3 l cc khi ng t vn gi nguyn.

-Phn t x l:c thay th bng PLC.

Hnh 1-4

Khi thc hin bng chng trnh iu khin c nh PLC ta ch cn thc hin

ni mch theo s sau:

S1

S2

K1

S3

K2

S4

K3

K2K1

K1 K2 K3

Nhps liu

X l

Kt qu

S1

S2 K1 S3 K2 S4 K3

K2K1

K1 K2 K3


4/94


Hnh 1-5:S ni dy thc hin bng PLC

Nu by gi nhim v iu khin thay i v d nh cc bm 1,2,3 hot ng

theo nguyn tc l ch mt trong s cc bm c hot ng c lp. Nh vy

i vi mch iu khin dng Rle ta phi tin hnh lp gip li ton b mch

iu khin, trong khi i vi mch iu khin dng PLC th ta li ch cn

son tho li chng trnh ri np li vo CPU th ta s c ngay mt s iu

khin theo yu cu nhim v mi m khng cn phi ni li dy trn mch iu

khin.

Nh vy mt cch tng qut c th ni h thng iu khin PLC l tp hp

cc thit b v linh kin in t. m bo tnh n nh, chnh xc v an ton..

trong qu trnh sn xut, cc thit b ny bao gm nhiu chng loi, hnh dng

khc nhau vi cng sut t rt nh n rt ln. Do tc pht trin qu nhanh

ca cng ngh v p ng c cc yu cu iu khin phc tp nn h thng

iu khin phi c h thng t ng ho cao. Yu cu ny c th thc hin c

bng h lp trnh c nh PLC kt hp vi my tnh, ngoi ra cn cn c cc thit

b ngoi vi khc nh: Bng iu khin, ng c, cm bin, tip im, cng tc

t,...

Kh nng truyn d liu trong h thng rt rng thch hp cho h thng x l

v cng rt linh ng trong cc h thng phn phi .

Mi mt thnh phn trong h thng iu khin c mt vai tr quan trng nh

c trnh by trong hnh v sau.

S1 S2 S3 S4

K1 K2 K3

PLC

24V

N

Nhp sliu

X l

Kt qu


5/94


Hnh 1-6: M hnh h thng iu khin PLC

H thng PLC s khng cm nhn

c th gii bn ngoi nu khng c cccm bin, v cng khng th iu khin c h thng sn xut nu khng c

cc ng c, xy lanh hay cc thit b ngoi vi khc nu cn thit c th s dng

cc my tnh ch ti cc v tr c bit ca dy chuyn sn xut .

1.1.1.H thng iu khin PLC in hnh :

Trong h thng iu khin PLC cc phn t nhp tn hiu nh : chuyn mch,

nt n, cm bin, ... c ni vi u vo ca thit b PLC. Cc phn t chp

hnh nh

: n bo, r le, cng tc t,...

c ni n li ra ca PLC ti cc uni.

Chng trnh iu khin PLC c son tho di cc dng c bn (s c

trnh by phn sau) s c np vo b nh bn trong PLC, sau t ng

thc hin tun t theo mt chui lnh iu khin c xc nh trc .

H cn cho php cng nhn vn hnh thao tc bng tay cc tip im, nt

dng khn cp m bo tnh an ton trong cc trng hp xy ra s c.

1.1.2.Vai tr ca PLC:

PLC c xem nh tri tim trong mt h thng iu khin t ng n l vi

chng trnh iu khin c cha trong b nh ca PLC, PC thng xuyn

kim tra trng thi ca h thng thng qua cc tn hiu hi tip t thit b nhp

t c th a ra nhng tn hiu iu khin tng ng n cc thit b xut.

Khi x l

trung tm

Giao tip ng

vo

B nh

Giao

tip

ng

ra

T tipimcmbin

n cundy, mt,....

Ngunnui


6/94


PLC c th c s dng cho nhng yu cu iu khin n gin v c lp

i lp li theo chu k, hoc lin kt vi my tnh ch khc hoc my tnh ch

thng qua mt kiu h thng mng truyn thng thc hin cc qu trnh x l

phc tp.

Tn hiu vo.

Mc thng minh ca mt h thng iu khin ph thuc ch yu vo

kh nng ca PLC c c cc d liu khc nhau t cc cm bin cng nh

bng cc thit b nhp bnh tay .

Tiu biu cho cc thit b nhp bng tay nh : Nt n, bn phm v chuyn

mch. Mt khc, o, kim tra chuyn ng, p sut, lu lng cht lng ...

PLC phi nhn cc tn hiu t cc cm bin. V d : Tip im hnh trnh, cm

bin quang in ... tn hiu a vo PLC c th l tn hiu s (Digital) hoc tn

hiu tng t (Analog), cc tn hiu ny c giao tip vi PLC thng qua cc

Modul nhn tn hiu vo khc nhau khc nhau DI (vo s) hoc AI (vo tng

t)....

i tng iu khin .

Mt h thng iu khin s khng c ngha thc t nu khng giao tip

c vi thit b xut, cc thit b xut thng dng nh: Mt, van, Rle, n

bo, chung in,... cng ging nh thit b nhp, cc thit bi xut c ni n

cc ng ra ca Modul ra (Output). Cc Modul ra ny c th l DO (Ra s) hoc

AO (ra tng t).

1.1.3.Cu to PLC.

Thit b iu khin lp trnh PLC bao gm khi x l trung tm (CPU) trong

c cha chng trnh iu khin v cc Modul giao tip vo/ra c nhim v

lin kt trc tip n cc thit b vo/ra, s khi cu to PLC c v nh

hnh 1-6.

Khi x l trung tm : l mt vi x l iu khin tt c cc hot ng ca

PLC nh: Thc hin chng trnh, x l vo/ra v truyn thng vi cc thit b

bn ngoi.

B nh: c nhiu cc b nh khc nhau dng cha chng trnh h thng

l mt phn mm iu khin cc hot ng ca h thng, s LAD, tr s ca


7/94


Timer, Counter c cha trong vng nh ng dng, ty theo yu cu ca ngi

dng c th chn cc b nh khc nhau:

B nh ROM: l loi b nh khng thay i c, b nh ny ch np cmt ln nn t c s dng ph bin nhcc loi b nh khc .

B nh RAM: l loi b nh c th thay i

c v dng cha ccchng trnh ng dng cng nh d liu, d liu cha trong Ram s b mt

khi mt in. Tuy nhin, iu ny c th khc phc bng cch dng Pin.

B nh EPROM: Ging nh ROM, ngun nui cho EPROM khng cn dngPin, tuy nhin ni dung cha trong n c th xo bng cch chiu tia cc tm

vo mt ca s nh trn EPROM v sau np li ni dung bng my np.

B nh EEPROM: kt hp hai u im ca RAM v EPROM, loi ny cth xa v np bng tn hiu in. Tuy nhin s ln np cng c gii hn.

1.1.4.u nhc im ca h thng :

Trong giai on u ca thi k pht trin cng nghip vo khong nm

1960 v 1970, yu cu t ng ca h iu khin c thc hin bng cc Rle

in t ni ni vi nhau bng dy dn in trong bng iu khin, trong nhiu

trng hp bng iu khin c kch thc qu ln n ni khng th gn ton b

ln trn tng v cc dy ni cng khng hon ton tt v th rt thng xy ra

trc trc trong h thng. Mt im quan trong na l do thi gian lm vic ca

cc Rle c gii hn nn khi cn thay th cn phi ngng ton b h thng vdy ni cng phi thay mi cho ph hp, bng iu khin ch dng cho mt yu

cu ring bit khng th thay i tc thi chc nng khc m phi lp gip li

ton b, v trong trng hp bo tr cng nh sa cha cn i hi th chuyn

mn c tay ngh cao. Tm li h iu khin Rle hon ton khng linh ng.

*Tm tt nhc im ca h thng iu khin dng Rle:

- Tn km rt nhiu dy dn .

- Thay th rt phc tp.- Cn cng nhn sa cha tay ngh cao.

- Cng sut tiu th ln .

- Thi gian sa cha lu.

- Kh cp nht s nn gy kh khn cho cng tc bo tr cng nh thay

th.


8/94


*u im ca h iu khin PLC:

S ra i ca h iu khin PLC lm thay i hn h thng iu khin

cng nh cc quan nim thit k v chng, h iu khin dng PLC c nhiu u

im nh sau:

- Gim 80% S lng dy ni.

- Cng sut tiu th ca PLC rt thp .

- C chc nng t chun on do gip cho cng tc sa cha c nhanh

chng v d dng.

- Chc nng iu khin thay i d dng bng thit b lp trnh (my tnh,

mn hnh) m khng cn thay i phn cng nu khng c yu cu thm bt cc

thit b xut nhp.

- S lng Rle v Timer t hn nhiu so vi h iu khin c in.

- S lng tip im trong chng trnh s dng khng hn ch.

- Thi gian hon thnh mt chu trnh iu khin rt nhanh (vi mS) dn n

tng cao tc sn xut .

- Chi ph lp t thp .

- tin cy cao.

- Chng trnh iu khin c th in ra giy ch trong vi pht gip thun tin

cho vn bo tr v sa cha h thng.

1.1.5.ng dng ca h thng iu khin PLC:

T cc u im nu trn, hin nay PLC c ng dng trong rt nhiu lnh

vc khc nhau trong cng nghip nh:

- H thng nng vn chuyn.

- Dy chuyn ng gi.

- Cc ROBOT lp gip sn phm .

- iu khin bm.

- Dy chuyn x l ho hc.

- Cng ngh sn xut giy .

- Dy chuyn sn xut thu tinh.

- Sn xut xi mng.

- Cng ngh ch bin thc phm.

- Dy chuyn ch to linh kin bn dn.

- Dy chuyn lp gip Tivi.

- iu khin h thng n giao thng.


9/94


- Qun l t ng bi u xe.

- H thng bo ng.

- Dy truyn may cng nghip.

- iu khin thang my.

- Dy chuyn sn xut xe t.

- Sn xut vi mch.

- Kim tra qu trnh sn xut .

1.2 H thng iu khin PLC S7-300.

1.2.1.Cu trc phn cng ca h thng PLC S7-300.

Thng thng, tng tnh mm do trong ng dng thc t m phn

ln cc i tng iu khin c s tn hiu u vo, u ra cng nh chng loi

tn hiu vo/ra khc nhau m cc b iu khin PLC c thit k khng b cng

ho v cu hnh. Chng c chia nh thnh cc modul. S cc Modul c s

dng nhiu hay t tu theo tng yu cu cng ngh, song ti thiu bao gi cng

phi c mt Modul chnh l cc modul CPU, cc modul cn li l cc modul

truyn nhn tn hiu i vi i tng iu khin, cc modul chc nng chuyn

dng nh PID, iu khin ng c, Chng c gi chung l Modul m rng.

Tt c cc modul c g trn nhng thanh ray (RACK).

Modul CPU:

L modul c cha b vi x l, h iu hnh, b nh, cc b thi gian, b

m, cng truyn thng (chun trynRS485) v c th cn c mt vi cng vo

ra s (Digital). Cc cng vo ra c trn modul CPU c gi l cng vo ra

onboard.

Trong PLC S7-300 c nhiu loi modul CPU khc nhau. Ni chung chng

c t tn theo b vi x l c trong n nh: CPU312, modul CPU 314, Modul

CPU 315,... Nhng modul cng s dng mt loi b vi x l, nhng khc nhau

v cng vo/ra onboard cng nh cc khi lm vic c bit c tch hp sn

trong th vin ca h iu hnh phc v vic s dng cc cng vo/ra onboard

ny s c phn bit vi nhau trong tn gi bng cch thm cm ch ci IFM

(Intergated Function Module) v d CPU 312IM, modul CPU 314 IFM.

Ngoi ra c cc loi modul CPU vi hai cng truyn thng, trong cng

truyn thng th hai c chc nng chnh l vic phc v ni mng phn tn. Tt

nhin c ci sn trong h iu hnh cc loi Modul CPU c phn bit vi

cc CPU khc bng thm cm t DP trong tn gi. V d Modul CPU 315-DP.


10/94


Modul m rng: cc modul m rng c chia lm 5 loi chnh:

1/ PS(Power supply): modul ngun nui. C 3 loi 2A ,5A v 10A.

Hnh 1-7:S b tr mt trm PLC( S7-300).

2/ SM: Modul m rng cng rn hiu vo ra , bao gm:

a) DI( Digital input): Modul m rng cng vo s. S cc cng vo camodul ny c th l 8, 16, 32 tu thuc vo tng loi modul.

b) DO(Digital output) Modul m rng cng ra s. S cc cng ra ca modulny c th l 8, 16, 32 tu thuc vo tng loi modul.

c) DI/DO: (Digital input/ Digital output): modul m rng cc cng vo/ra ss cc cng vo/ra c th l 8 vo/8 ra hoc 16 vo/16 ra tu thuc vo

tng loi modul.

d) AI(Analog Input): Modul m rng cc cng vo tng t. V bn chtchng chnh l nhng b chuyn i tng t-s (AD), tc l mi tn hiu

tng t c chuyn thnh mt tn hiu s (nguyn ) c di 12 bt, s

cc cng vo c th l 2, 4 hoc 8 tu thuc vo tng loi Modul.e) AO(Analog ouput): Modul m rng cc cng ra tn hiu tng t. Chngchnh l cc b chuyn i s - tng t (DA). S cc cng ra tng t c

th l 2 hoc 4 tu thuc tng loi modul.

f) AI/AO ( Analog input/Analog output): Modul m rng cc cng vo ratng t. S cc cng c th l 4 vo/2 ra hoc 4 vo/4 ra tu thuc vo

tng loi modul.


11/94


3/ IM (Interface module): Modul ghp ni. y l loi modul chuyn dng

c nhim v ni tng nhm cc modul m rng li vi nhau thnh mt khi

v c qun l chung bi mt modul CPU. Thng thng cc modul m

rng c g lin vi nhau trn mt thanh gi l Rack. Trn mi mt

Rack ch c th g c nhiu nht 8 modul m rng (khng k modul CPU,

Modul ngun nui). Mt modul PU S7-300 c th lm vic trc tip c vi

nhiu nht 4 RACKS v cc Racks ny phi c ni vi nhau bng modul

IM.

4/ FM (Function modul): modul c chc nng iu khin ring , v d Modul

chc nng iu khin ng c bc , modul iu khin ng c Servo, modul

PID, modul iu khin vng kn.

5/ CP (communication modul): Modul phc v truyn thng trong mng gia

cc PLC vi nhau hoc gia PLC vi my tnh.

1.2.2.Kiu d liu v phn chia b nh:

1-Phn loi:

Mt chng ttrnh trong S7-300 c th s dng cc kiu d liu sau:

1/ BOOL: vi dung lng l 1 bit v c gi tr l 0 hoc 1 (ng hoc sai).

y l kiu d liu bin c hai gi tr.

2/ BYTE: gm 8 bits, thng c dng biu din mt s nguyn dng

trong khong t 0 n 255 hoc m ASCII ca mt t.

V d: B#16#14 ngha l s nguyn 14 vit theo h m c s 16 c

di 1 byte.

3/ WORD: gm 2 byte, biu din s nguyn dng t 0 n 65535 (216 -

1).

4/DWORD: L t kp c gi tr l: 0 n 232-1.

5/ INT: cng c dung lng l 2 bytes, dng biu din mt s nguyn

trong khong -32768 n 32767 hay ( 2-15...215-1).

6/ DINT: gm 4 bytes, dng biu din s nguyn t -2147483648 n

2147483647 hay: (2-31....231-1).

7/ REAL: gm 4 bytes, dng biu din mt s thc du phy ng c gi

tr l: -3,4E38.....3,4E38.

V d: 1.234567e+13

8/ S5t (hay S5Time): khong thi gian, c tnh theo gi/pht/giy: (-2-31+

231-1 ms).


12/94


V d: S5t#2h_3m_0s_5ms.

y l lnh to khong thi gian la 2 ting ba pht v 5 mili giy.

9/TOD: Biu din gi tr tc thi tnh theo Gi/pht/giy.

V d: TOD#5:30:00 l lnh khai bo gi tr thi gian trong ngy l 5 gi

30 pht.

10/ DATE: Biu din thi gian tnh theo nm / ngy / thng.

V d: DATE#2003-6-12

L lnh khai bo ngy12 thng 6 nm 2003.

11/ CHAR: biu din mt hoc nhiu k t (nhiu nht l 4 k t) (ASCII -

code).

V d: ABCD

2-S dng v khai bo cc dng tn hiu:Trong qu trnh thc hin cu trc ca tn hiu s c biu din di dng:

1/ Bit : (v d I0.0) dng biu din s nh phn (c 2 gi tr 1 hoc 0).

1

2/ Byte : (v d MB0) Mt Byte gm c 8 bits. V d gi tr ca 8 cng vo (IB0)

hoc 8 cng ra (QB1),... c gi l mt byte:

0 0 1 1 0 1 0 1

3/ Word: (v d MW0= MB0 + MB1) Mt Word gm c 2 Byte nh vy mt

Word c di 16 bits.

0 0 1 0 1 1 1 0 0 0 1 0 1 1 1 0

Byte 0 Byte 1

4/ Doppelword: (v d MD0 = MW0 + MW2): c di 2 t hoc 4 Byte tc l

32 bits.


13/94


1.2.3.Cu trc b nh ca CPU ca S7-300:

c chia ra lm 3 vng chnh:

1) Vng cha chng trnh ng dng: vng nh chng trnh c chia lm3 min:

a/ OB: Min cha chng trnh t chc (cc chng trnh ny s c gii

thiu mc 1.2.5).

b/ FC: (Funktion): min cha chng trnh con c t chc thnh hm

c bin hnh thc trao i d liu vi chng trnh gi n.

c/ FB: (Funktion Block): Min cha chng trnh con, c t chc thnh

hm v c kh nng trao i d liu vi bt c mt khi chng trnh no

khc. Cc d liu ny phi c xy dng thnh mt khi d liu ring

(gi lDB-Data block).

2) Vng cha cc tham s ca h iu hnh v chng trnh ng dng, cphn chia thnh 7 min khc nhau, bao gm:

a. I (Procees image input): min b m cc d liu cng vo s. Trc khi

thc hin chng trnh, PLC s c gi tr logic ca tt c cc u vo v

ct gi chng trong vng nh I. Thng thng chng trnh ng dng

khng c trc tip trng thi logic ca cng vo s m ch ly d liu ca

cng vo t b m I.

b. Q (Process image output): min b m cc cng ra s. Kt thc giai on

thc hin chng trnh s chuyn gi tr logic ca b m ti cc cng ra

s. Thng thng khng trc tip gn gi tr ti tn cng ra m ch

chuyn chng vo b m Q.

c. M: Min cc bin c. Chng trnh ng dng s dng vng nh ny lu

gi cc tham s cn thit v c th truy cp n theo bit (M), byte (MB), t

(MW) hay t kp (MD).

d. T: Min nh phc v b thi gian (TIME) bao gm vic lu gi gi tr thi

gian t trc (PV-preset value), gi tr m thi gian tc thi (CV-

Curren value) cng nh cc gi tr logic u ra ca b thi gian.

e. C: Min nh phc v b m (counter) bao gm vic lu gi gi tr t

trc (PV), v gi tr m tc thi (CV) v gi tr logic u ra ca b m.

f. PI: Min a ch cng vo ca cc modul tng t. Cc gi tr tng t ticng vo ca modul tng t s c c v chuyn t ng theo nhng

a ch. Chng trnh ng dng c th truy nhp min nh PI theo tng

byte (PIB), tng t (PIW) hoc theo t kp (PID).


14/94


g. PQ: min a ch cng ra cho cc modul tng t. Cc ga tr theo nhng

a ch ny c modul tng t chuyn ti cc cng ra tng t. Chng

trnh ng dng c th truy cp min nh PQ theo tng byte (PQB), tng t

(PQW) hay tng t kp (PQD)

3) Vng cha cc khi d liu: c chia lm hai loi:a. DB (Data block): min cha cc d liu c t chc thnh khi. Kch

thc cng nh s lng do ngi s dng qui nh, ph hp vi tng bi

ton iu khin. Chng trnh c th truy cp min ny theo tng bit

(DBX), byte (DBB), t (DBW) hoc t kp (DBD).

b. L (Local data block) : min gi liu a phng, c cc khi chngtrnh OB, FB, FC t chc v s dng cho cc bin nhp tc thi v trao

i gi liu ca bin hnh thc ca chng trnh vi nhng khi chng

trnh gi n. Ni dung ca mt s d liu trong min nh ny s b xo

khi kt thc chng trnh tng ng trong OB, FB, FC. Min ny c th

truy cp t chng trnh theo bit (L), byte (LB), t (LW) hay t kp (LD).

1.2.4.Vng qut ca chng trnh:

SPS (PLC) thc hin cc cng vic (bao gm c chng trnh iu khin)

theo chu trnh lp. Mi vng lp c gi l mt vng qut (scancycle). Mi

vng qut c bt u bng vic chuyn d liu t cc cng vo s ti vng b

m o I, tip theo l giai on thc hin chng trnh. Trong tng vng qut ,

chng trnh c thc hin t lnh u tin n lnh kt thc ca khi OB1.

Sau giai on thc hin chng trnh l giai on chuyn cc ni dung ca b

m o Q ti cc cng ra s. Vng qut c kt thc bng giai on x l cc

yu cu truyn thng (nu c) v kim tra trng thi ca CPU. Mi vng qut c

th m t nh sau:

Hnh1-8: Qu trnh hot ng ca mt vng qut.

Ch : B m I v Q khng lin quan ti cc cng vo/ra tng t nn cc lnh

truy nhp cng tng t c thc hin trc tip vi cng vt l ch khng

thng qua b m.

Vng qut

Truyn d liu tcng vo ti I

Truyn thng vkim tra ni b

Chyn d liut Q ti cngThc hinchng trnh


15/94


Thi gian cn thit cho PLC thc hin c mt vng qut c gi l

thi gian vng qut (Scan time). Thi gian vng qut khng c nh, tc l

khng phi vng qut no cng c thc hin trong mt khong thi gian nh

nhau. C vng qut c thc hin lu, c vng qut c thc hin nhanh tu

thuc vo s lnh trong chng trnh c thc hin, vo khi lng d liu

truyn thng. Trong vng qut .

Nh vy gia vic c d liu t i tng x l, tnh ton v vic gi tn

hiu iu khin n i tng c mt khong thi gian tr ng bng thi gian

vng qut. Ni cch khc, thi gian vng qut quyt nh tnh thi gian thc ca

chng trnh iu khin trong PLC. Thi gian vng qut cng ngn, tnh thi

gian thc ca chng trnh cng cao.

Nu s dng cc khi chng trnh c bit c ch ngt, v d khi OB40,

OB80,... Chng trnh ca cc khi s c thc hin trong vng qut khi

xut hin tn hiu bo ngt cng chng loi. Cc khi chng trnh ny c th

thc hin ti mi vng qut ch khng phi b g p l phi trong giai on

thc hin chng trnh. Chng hn mt tn hiu bo ngt xut hin khi PLC ang

giai on truyn thng v kim tra ni b, PLC s tm dng cng vic truyn

thng, kim tra, thc hin ngt nh vy, thi gian vng qut s cng ln khi

cng c nhiu tn hiu ngt xut hin trong vng qut. Do nng cao tnh

thi gian thc cho chng trnh iu khin, tuyt i khng nn vit chng

trnh x l ngt qu di hoc qu lm dng vic s dng ch ngt trong

chng trnh iu khin.

Ti thi im thc hin lnh vo/ra, thng thng lnh khng lm vic trc

tip vi cng vo/ra m ch thng qua b nh m ca cng trong vng nh

tham s. Vic truyn thng gia b m o vi ngoi vi trong giai on 1 v 3

do h iu hnh CPU qun l. mt s modul CPU, khi gp lnh vo/ra ngay

lp tc h thng s cho dng mi cng vic khc, ngay c chng trnh x l

ngt, thc hin vi cng vo/ra.

1.2.5. Nhng khi OB c bit:Khi OB1 c chc nng qun l chnh trong ton b chng trnh, c ngha

l n s thc hin mt cch u n tng vng qut trong khi thc hin

chng trnh. Ngoi ra Step7 cn c rt nhiu cc khi OB c bit khc v mi

khi OB c mt nhim v khc nhau, v d cc khi OB cha cc chng


16/94


trnh ngt ca cc chng trnh bo li ,....Tu thuc vo tng loi CPU khc

nhau m c cc khi OB khc nhau. V d cc khi OB c bit.

1. OB10: (Time of Day Interrupt): Chng trnh trong khi OB10 s c thchin khi gi tr ca ng h thi gian thc nm trong mt khong thi gian

qui nh. OB10 c th c gi mt ln, nhiu ln cch u nhau tng

pht, tng gi, tng ngy,....Vic qui nh thi gian hay s ln gi OB10

c thc hin bng chng trnh h thng SFC28 hoc trong bng tham s

modul CPU nh phn mm Step7.

2. OB20: (Time Delay Interrupt): chng trnh trong khi OB20 s c thchin sau mt khong thi gian tr t trc k t khi gi chng trnh h

thng SFC32 t thi gian tr.

3. OB35: (Cyclic Interrupt): Chng trnh OB35 s c thc hin cch unhau mt khong thi gian c nh. Mc nh khong thi gian ny l

100ms, xong ta c th thay i trong bng t tham s cho CPU nh phn

mm Step7.

4. OB40 ( Hardware Interrupt): Chng trnh trong khi OB40 s c thchin khi xut hin mt tn hiu bo ngt t ngoi vi a vo CPU thng qua

cc cng vo/ra s onboard c bit, hoc thng qua cc modul SM, CP, FM.

5. OB80: (cycle Time Fault): Chng trnh s c thc hin khi thi gian vngqut (scan time) vt qua khong thi gian cc i qui nh hoc khi c

mt tn hiu ngt gi mt khi OB no m khi OB ny cha kt thc

ln gi trc. Mc nh, scan time cc i l 150ms, nhng c th thay i

tham s nh phn mm Step7.

6. OB81( Power Supply Fault): nu c li v phn ngun cung cp th s gichng trnh trong khi OB81.

7. OB82: (Diagnostic Interrupt) chng trnh trong khi ny s c gi khiCPU pht hin c li t cc modul vo/ra m rng. Vi iu kin cc modul

vo/ra ny phi c chc nng t kim tra mnh.

8. OB85 (Not Load Fault): CPU s gi khi OB85 khi pht hin chng trnhng dng c s dng ch ngt nhng chng trnh x l tn hiu ngt li

khng c trong khi OB tng ng.

9. OB87 (Communication Fault): Chng trnh trong khi ny s c gi khiCPU pht hin thy li trong truyn thng.

10.OB100 (Start Up Information): Khi ny s c thc hin mt ln khi CPUchuyn trng thi t STOP sang trng thi RUN.


17/94


11.OB121: (Synchronouns error): Khi ny s c gi khi CPU pht hin thyli logic trong chng trnh nh i sai kiu d liu hoc li truy nhp khi

DB, FC, FB khng c trong b nh ca CPU.

12.OB122 ( Synchronouns error): Khi ny s c thc hin khi CPU phthin thy li truy nhp Modul trong chng trnh, v d trong chng trnh

c lnh truy nhp modul m rng nhng li khng c modul ny.

thc hin thay i cc chc nng ca cc khi OB trong CPU ta ch cn

kch p chut tri vo v t CPU trong bng cu hnh cng ca Project khi

trn mn hnh s xut hin mt ca s nh sau:

Hnh 1-9

Ch khng phi tt c cc CPU u c cc khi OBs nh gii thiu. S

lng v chng loi khi OB tu thuc vo tng loi CPU.


18/94


Chng 2: K thut lp trnh:

2.1.Gii thiuchung:

2.1.1.Lp trnh tuyn tnh v lp trnh c cu trc:

Phn b nh ca CPU dnh cho chng trnh ng dng c tn gi l logic

Block. Nh vy logic block l tn chung gi tt c cc khi bao gm nhng

khi chng trnh t chc OB, khi chng trnh FC, khi hm FB. Trong cc

loi khi chng trnh th ch c khi duy nht khi OB1 c thc hin trc

tip theo vng qut. N c h iu hnh gi theo chu k lp vi khng thi

gian khng cch u nhau m ph thuc vo di ca chng trnh. Cc loi

khi chng trnh khc khng tham gia vo vng qut.Vi t chc chng trnh nh vy th phn chng trnh trong khi OB1 c

y iu kin ca mt chng trnh iu khin thi gian thc v ton b

chng trnh ng dng c th ch cn vit trong OB1 l nh hnh v sau.

Cch t chc chng trnh vi ch mt khi OB1 duy nht nh vy c gi l

lp trnh tuyn tnh.

Hnh 2-1: S khi kiu lp trnh tuyn tnh

Khi OB1 c h thng gi xoay vng lin tc theo vng qut.

Cc khi OB khc khng tham gia vo vng qut c gi bng nhng tn

hiu bo ngt. S7-300 c nhiu tn hiu bo ngt nh tn hiu bo ngt khi c s

c ngun nui, c s c chp mch cc modul m rng, tn hiu bo ngt theo

chu k thi gian, v mi loi tn hiu bo ngt nh vy cng ch c kh nng gi

OB1 thchin theovng qut

OB82 Modulchun on li

OB10 Nght

thi im nhtrc


19/94


mt khi OB nht nh. V d tn hiu bo ngt s c ngun nui ch gi khi

OB81, tn hiu bo ngt truyn thng ch gi khi OB87.

Mi khi xut hin tn hiu bo ngt h thng s dng cng vic ang thc

hin li, chng hn nh tm dng vic thc hin chng trnh trong OB1, v

chuyn sang thc hin chng trnh x l ngt tong cc khi OB tng ng. V

d khi ang thc hin chng trnh trong khi OB1 m xut hin ngt bo s c

truyn thng, h thng s tm dng vic thc hin chng trnh trong OB1 li

gi chng trnh trong khi truyn thng OB87. Ch sau khi thc hin xong

chng trnh trong khi OB87 th h thng mi quay tr v hc hin tip tc

phn chng trnh cn li trong OB1.

Vi kiu lp trnh c cu trc th khc v ton b chng trnh iu khin

c chia nh thnh cc khi FC v FB mang mt nhim v c th ring v

c qun l chung bi nhng khi OB. Kiu lp trnh ny rt ph hp cho

nhng bi ton phc tp, nhiu nhim v v li rt thun li cho vic sa cha

sau ny.

Hnh 2-2: S kiu lp trnh c cu trc.

OB: Organization Block

FB: Function Block

FC: Function

SFB: System Function block

SFC: System function

SDB: System Data Block

DB: Data block

Ch : Bao giFB cng s dng chung viDB.

OB

FB FC

FBFB

SFB

SFC

DB

DBDB

DB


20/94


2.1.2.Qui trnh thit k chng trnh iu khin dng PLC:

Qui trnh thit k h thng iu khin dng PLC bao gm cc bc sau:

1.Xc nh qui trnh iu khin:

iu u tin cn bit l i tng iu khin ca h thng, mc ch cnh

ca PLC l phi iu khin c cc thit b ngoi vi. Cc chuyn ng ca i

tng iu khin c kim tra thng xuyn bi cc thit b vo, cc thit b

ny gi tn hiu n PLC v tip theo PLC s a tn hiu iu khin n cc

thit b iu khin chuyn ng ca i tng. n gin, qui trnh iu

khin c th m t theo lu (hnh v 2-3).

2.xc nh tn hiu vo ra:

Bc th hai l phi xc nh v tr kt ni gia cc thit b vo ra vi PLC.

Thit b vo c th l tip im, cm bin, Thit b ra c th l Rle in t,

Motor, n, Mi v tr kt ni c nh s tng t ng vi PLC s dng.

3.Son tho chng trnh:

Chng trnh iu khin c son tho di dng lu hnh thang nh

trnh by bc 1.

4.Np chng trnh vo b nh:

Cp ngun cho PLC, ci t cu hnh khi giao tip I/O nu cn (Ph thuc

vao tng loi PLC). Sau np chng trnh son tho trn mn hnh vo b nh

ca PLC. Sau khi hon tt nn kim tra li bng chc nng t chun on v nu

c th th chy chng trnh m phng hot ng ca h thng (V d chng

trnh S7-SIM, S7- VISU,...).

5.Chy chng trnh:

Trc khi khi ng h thng cn phi chc chn dy ni t PLC n cc

thit b ngoi vi l ng, trong qu trnh chy kim tra c th cn thit phi thc

hin cc bc tinh chnh h thng nhm m bo an ton khi a vo hot ng

thc t.


21/94


Qui trnh thit k h thng iu khin bng PLC:

Hnh 2-3: Qui trnh thit k mt h thng iu khin t ng.

NO

Xc nh yu cuca h thng

V lu iukhin

Lit k cc thit

b I/Otng ngvi cc u I/Oca PLC

Son thochng trnh

Np chng trnhvo PLC

Chy m phngv tm li

Sa cha chngtrnh

Kt ni cc thitb I/O vo PLC

Kim tra dy ni

Chy th chng

trnh

Kim tra

Np vo EPROM

To ti liuchng trnh

Chm dtChy tt?

Chy tt?

YESNO

YES


22/94


2.2.Cc ngn ng lp trnh:

i vi PLC S7-300 c th s dng 6 ngn ng lp trnh.

1/ Ngn ng lp trnh LAD:

Vi loi ngn ng ny rt thch hp vi ngi quen thit k mch iu khin

logic

chng trnh c vit di dng lin kt gia cc cng tc:

v d:

Hnh 2-4: v d kiu lp trnh LAD.


23/94


2/ Ngn ng lp trnh FBD :

Loi ngn ng ny thch hp cho nhng ngi quen s dng v thit k mch

iu khin s.

Chng trnh c vit di dng lin kt ca cc hm logic k thut s:

V d:

Hnh 2-5: V d kiu lp trnh FBD.

3/ Ngn ng lp trnh STL

y l ngn ng lp trnh thng thng ca my tnh. Mt chng trnh c

ghp bi nhiu lnh theo mt thut ton nht nh, mi lnh chim mt hng v

u c cu trc chung l : "tn lnh" + "ton hng".

V d:

Hnh 2-6: V d kiu lp trnh STL.


24/94


4/ Ngn ng lp trnh SCL (Structured Control Language):

Kiu vit chng trnh ny s dng ngn ng PASCAL. Rt ph hp cho

nhng ngi vit cc chng trnh bng ngn ng my tnh.

v d:

5/ Ngn ng lp trnh : S7-Graph.

V d:

Hnh2-7:S khi lp trnh kiu S7-Graph.


25/94


6/ Ngn ng lp trnh : S7-HiGraph.

y l mt loi ngn ng vit chng trnh rt ph hp cho cc bi ton lm

vic c tnh tun t. Ti mi thi im ch c mt bc c thc hin. Vi kiu

lp trnh ny ngi lp trnh phi s dng phng php lp trnh c cu trc.

V d:

Hnh 2-8 : S lp trnh bng ngn ng S7-HiGraph.

Trong cun ti liu ny s gii thiu 4 loi ngn ng dng lp trnh (FBD,

STL, LAD v S7GRAPH) trong phn bi tp mu.


26/94


Chng 3: Ci t phn mm S7-300 v chn ch lm vic

3.1. Gii thiu chung:

Mun xy dng mt chng trnh iu khin s dng phn mm Step7 cn thchin cc th tc nh sau:

- Khai bo cu hnh cng cho mt trm PLC thuc h Simatic S7-300/400.- Xy dng cu hnh mng gm nhiu trm PLC S7-300/400 cng nh th tc

truyn thng gia chng.

- Son tho v ci t chng trnh iu khin cho 1 hoc nhiu trm.- Gim st vic thc hin chng trnh iu khin trong mt trm PLC v g

ri chng trnh.

Ngoi ra Step 7 cn c c mt th vin y vi cc hm chun hu ch, phntr gip Online rt mnh c kh nng tr li mi cu hi ca ngi s dng v

cch s dng Step 7, v c php lnh trong lp trnh, v xy dng cu hnh cng

ca mt trm cng nh ca mt mng gm nhiu trm PLC.

3.2. Ci t Step7:

3.2.1.Tng qut v Step 7

Ti vit nam hin c rt nhiu phin bn ca b phn mm gc ca Step7.

ang c s dng nhiu nht l phin bn (version) 4.2, 5.0 v 5.1. Trong khiphin bn 4.2 kh ph hp cho nhng PC c cu hnh trung bnh (CPU 80586,

90MB cn trng trong cng, mn hnh VGA) nhng li i hi tuyt i c

bn quyn. Trong khi phin bn 5.0 v 5.1 mc d i hi my tnh c cu hnh

mnh nhng li khng i hi bn quyn mt cch tuyt i, ngha l phin bn

ny vn lm vic mt mc hn ch khi khng c bn quyn. Phn ln cc a

gc ca Step7 u c kh nng t ci t chng trnh (autorun). Bi vy ch cn

cho a vo CD v thc hin theo ng ch dn hin trn mn hnh. Ta c th

ch ng thc hin vic ci t bng cch gi chng trnh Setup.exe c trna. Cng vic ci t, v c bn khng khc nhiu so vi vic ci t cc phn

mm ng dng khc, tc l cng bt u bng vic chn ngn ng ci t ( mc

nh l ting Anh), chn th mc t trn cng (mc nh l C:\simens), kim

tra dung tch cn li trn cng, chn ngn ng s c s dng trong qu trnh

lm vic vi Step7 sau ny.


27/94


Mt s vn cn gii thch r thm khi ci t phn mm Step7:(cun ti

liu ny hng dn cc bn ci t bng ngn ng ting Anh) nhng v c bn

ci t bng ting c cng khng c nhiu iu khc bit.

3.2.2 Khai bo m hiu sn phm: m hiu sn phm lun i km vi sn

phm v c in ngay trn a cha b ci Step7. Khi trn mn hnh xut hin

ca s yu cu cho bit m hiu sn phm, ta phi in y vo tt c cc th

mc ca ca s , k c a ch ngi s dng sau n continue tip tc.

Hnh 3-1: Khai bo m hiu ca sn phm

3.2.3.Chuyn bn quyn: Bn quyn Step7 nm trn mt a mm ring

(thng c mu vng hoc mu ). Trong qu trnh ci t, trn mn hnh s

xut hin yu cu chuyn bn quyn sang ch (mc nh l c:\ ) c dng nh

sau:

Ta c th chuyn bn quyn sang a C:\ ngay trong khi ci t Step7 bng

cch cho a bn quyn vo a A: ri n phm Authorize. Ta cng c th b

qua v s chuyn bn quyn sau vo lc khc bng cch n phm Skip. Trong

trng hp b qua th sau ny, lc chuyn bn quyn, ta phi s dng chng

trnh truyn bn quyn c tn l AuthorsW.EXE cng c trn a bn quyn

(Ver.4.2) hoc c cng trong a CD vi phn mm gc Step7 (ver5.1).


28/94


Hnh 3-2: Chuyn bn quyn

Ch a mm cha bn quyn (Author disk) c bo v cm sao chp.

Cho d bn quyn c chuyn t a mm sang cng v trn a mm

khng cn bn quyn, nhng n vn l mt a c bit c ch cha bn quyn.

Bn quyn khi sao chp sang a cng s nm trong thmc Ax nf zz. Nu th

mc ny b hng, ta s mt bn quyn. Bi vy mi khi mun ci t li h

thng hay dn dp li a cng th trc ta phi thc hin rt bn quyn

khi a C: v chuyn ngc v a mm Author cng bng chng trnh

AuthorsW.EXE.

3.2.4.Khai bo thit b t EPROM: Chng trnh step7 c kh nng t

chng trnh ng dng ln th EPROM cho PLC. Nu my tnh PC ca ta c

thit b t EPROM th cn phi thng bo cho Step7 bit khi trn mn hnh

xut hin ca s:


29/94


Hnh 3-3: Khai bo thit b t EPROM

3.2.5. Chn giao din cho PLC:Chng trnh Step7 c ci t trn PC (my tnh c nhn) hoc PG (lp

trnh bng tay) h tr vic son tho cu hnh cng cng nh chng trnh

cho PLC, tc l sau ton b nhng g son tho s c dch sang PLC.

Khng nhng th, Step7 cn c kh nng quan st vic thc hin chng trnh

ca PLC. Mun nh vy ta cn phi c b giao din ghp ni gia PC vi PLC

truyn thng tin, d liu.

Step7 c th ghp ni vi PLC bng nhiu b phng thc ghp ni khc

nhau nh qua Card MPI, qua b chyn i PC/PPI, qua th PROFIBUS (CP)

nhng chng phi c khai bo s dng.

Ngay sau khi Step7 c ci t xong, trn mn hnh xut hin ca s thng

bo cho ta chn cc b giao din s c s dng. Ca s ny c dng sau

(hnhv 3-4):

Mun chn b giao din no, ta nh du b giao din pha tri ri n

phm Install.... Nhng b giao din c chn s c ghi vo bn phi.

Sau khi chn xong cc b giao din s dng, ta cn phi t tham s lm vic

cho nhng b giao din bao gm tc truyn , cng ghp ni vi my tnh.

Chng hn khi chn b giao din MPI -ISA Card ta phi t tham s lm vic

cho n thng qua ca s mn hnh.

Khng c thit b tEPROMC thit b t EPROMca PGThit b t EPROM

bn n oi


30/94


Hnh3-4: Khai bo dng kt ni PC vi CPU

3.3.t tham s lm vic:

Sau khi ci t xong Step7, trn mn hnh (Destop) s xut hin biu tng

icon ca n. ng thi trong Menu ca Window cng c th mc Simatic vi

tt c cc tn ca nhng thnh phn lin quan, t cc phn mm tr gip n cc

phn mm ci t cu hnh, ch lm vic ca Step7.

Khi va c ci t, step7 c cu hnh mc nh v ch lm vic ca

Simatic, chng hn c php cc lnh li c vit theo ting c v d nh

AND th vit thnh UND, mun chuyn thnh dng thng dng quc t ta phi

ci t li cu hnh cho Step7.

Tt nhin, bn cnh vic chn ngn ng cho c php lnh ta cn c th sa

i nhiu chc nng khc ca Step 7 nh ni s cha chng trnh trn a cng,

nhng thanh ghi s c hin th ni dung khi g ri chng trnh, song cc vic

khng nh hng quyt nh ti vic s dng Step7 theo thi quen ca ta nh

ngn ng c php lnh.

3.4.Son tho mt Project.

Khi nim Project khng n thun ch l chng trnh ng dng m rng

hn bao gm tt c nhng g lin quan n vic thit k phn mm ng dng

iu khin, gim st mt hay nhiu trm PLC. Theo khi nim nh vy, trong

mt Project s c:

1. Bng cu hnh cng v tt c cc module ca tng trm PLC.


31/94


2. Bng tham s xc nh ch lm vic cho tng module ca mi trm PLC.3. Cc Logic block cha chng trnh ng dng ca tng trm PLC.4. Cu hnh ghp ni v truyn thng gia cac trm PLC.5. Cc ca s giao din phc v vic gim st ton b mng hoc gim st tng

trm PLC ca mng.

y, trong khun kh phn mm Step7 ti ch gii thiu vic son tho mt

Project gm cc phn 1,2,3. Nhng phn cn li bn c c th tham kho trong

cun ti liu khc ca cng tc gi.

3.4.1.Khai bo v m mt Project mi.

khai bo mt Project, t mn hnh chnh ca Step 7 ta chn File-> New

hoc kch chut ti biu t

ng "New Project/ Library".

Hnh 3-5: M mt Project mi

Khi trn mn hnh s xut hin hp hi thoi nh hnh 3-6. G tn Project

ri n phm OK v nh vy ta khai bo song mt Project mi. Ngoi ra ta cn

c th chn ni Project s c ct ln a. Mc nh, ni ct s l th mc

c quy nh khi ci t Step 7, y l th

mc F:\S7_ projects.

Khai bo mtProject mi

M mtProject c


32/94


Hnh 3-6: t tn cho mt Project mi

Trong trng hp mun m mt Project c, ta chn File -> Open hoc

kch chut ti biu tng "Open Project/ Library" t ca s chnh ca Step7 ri

chn tn Project mun m t hp hi thoi c dng nh hnh 3-7. Cui cng n

phm OK kt thc.

Hnh 3-7: M mt Project c.

Ni vit tn mt Project mi

Ni Project mi s c cttrn a

Tn ca mtProject csn


33/94


3.4.2. Xy dng cu hnh cng cho trm PLC.

Sau khi khai bo xong mt Project mi, trn mn hnh s xut hin Project

nhng dng rng (cha c g trong project), iu ny ta nhn bit c qua

biu tng th mc bn cnh tn Project ging nh mt th mc rng ca

Window.

Hnh 3-8: Biu tng mt Project mi.

Cng vic tip theo ta c th lm l xy dng cu hnh cng cho mt trm

PLC. iu ny khng bt buc, ta c th khng cn khai bo cu hnh cng cho

trm m i ngay vo phn chng trnh ng dng. Song kinh nghim cho thy

cng vic ny nn lm v khi c cu hnh trong project, lc bt ngun PLC, h

iu hnh ca S7-300 bao gi cng i kim tra cc module hin c trong trm,

so snh vi cu hnh m ta xy dng v nu pht hin thy s khng ng nht

s pht ngay tn hiu bo ngt li hoc thiu module ch khng cn phi i ti

khi thc hin chng trnh ng dng.

Trc ht ta khai bo cu hnh cng cho mt trm PLC vi simatic S7-300

bng cch vo: Insert -> Station ->Simatic 300- Station:

Biu tng mtth mc rng


34/94


Hnh 3-9: Khai bo cu hnh cng cho trm PLC

Trong trng hp khng mun khai bo cu hnh cng m i ngay vo

chng trnh ng dng ta c th chn thng. ng tc ny s hu ch cho nhng

trng hp mt trm PLC c nhiu phin bn ng dng khc nhau.

Sau khi khai bo mt trm (chn mt Station), th mc Project chuyn

sang dng khng rng vi th mc con trong n tn mc nh l Simatic300(1)

cha tp thng tin v cu hnh cng ca trm.

Hnh 3-10:Mn hnh khai bo cu hnh cng cho tm PLC

Khai bo

mt trmPLC S7-300

Tp chathng tinv cuhnh cngca trm


35/94


vo mn hnh khai bo cu hnh cng, ta nhy chut ti biu tng

Hardware. Trong hp thoi hin ra ta khai bo thanh Ray (Rack) v cc module

c trn thanh Ray .

V d:

Hnh 3-11: Th vin ly cc Modul

Step7 gip vic khai bo cu hnh cng c n gin nh bng danh mc

cc module ca n. Mun a module no vo bng cu hnh ta ch cn nh

du v tr ni module s c a vo ri nhy kp chut tri ti tn ca module

trong bng danh mc cac module km theo.

3.4.3. t tham s quy nh ch lm vic cho module.

Vi bng cu hnh cng phn mm Step7 cng xc nh lun cho ta a ch

tng module.

Chng hn Step7 c h tr vic tch cc ngt theo thi im cho module CPU

module ny pht mt tn hiu ngt gi khi OB10 mt ln vo ng ngy

16/02/2003 lc 10 gi 30. lm c iu ny ta nhy p chut ti tn ca

module CPU v tr 2 ri chn Time-Of-Day Interrupt, trn mn hnh s xut

hin hp hi thoi nh hnh 3-12. in thi im, tn sut pht tn hiu ngt ri

nh du tch cc ch ngt vo cc tng ng trong hp hi thoi. Cui

cng n phm OK.

Bngdanh mcccmodul la chn


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Hnh 3-12: t tham s cho Modul CPU

Cng trong hp hi thoi ta thy module CPU314 ch cho php s dng

OB10 trong s cc module OB10 - OB17 vi mc u tin l cha chng

trnh x l tn hiu ngt theo thi im.

Cc ch lm vic khc ca module CPU cng c quy nh nh Step7.

V d sa i thi gian vng qut cc i cho php t gi tr mc nh 150ms

thnh 100 ms, ta chn Cycle/Clock memory trong hp hi thoi ri sa ni dung

Scan time thnh 100.

Hon ton tng t ta cng c th s dng Step7 quy nh ch lm

vic cho cc module m rng khc, nh xc nh ch lm vic vi dng tn

hiu in p, vi di 5V cho module AI:

Thi impht tn

hiu ngt

tn hiu ngtc phtmt ln

Tch cctn hiu

ngt


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Hnh 3-13: t ch cho Modul Analog

3.4.4. Son tho chng trnh cho cc khi logic.

Sau khi khai bo cu hnh cng cho mt trm PLC v quay tr v ca s

chnh ca Step7 ta thy trong th mc Simatic 300(1) by gi c thm cc th

mc con v tt nhin ta c th i tn cc th mc .

Tt c cc khi Logic (OB, FC, FB, DB) cha chng trnh ng dng s nm

trong thmc Block. Mc nh trong th mc ny c sn khi OB1.

1.Son tho chng trnh cho khi OB1:

Ta nhy chut ti biu tng OB1 bn na ca s bn phi. Trn mn hnh s

xut hin ca s ca ch son tho chng trnh nh hnh 3-14.

Chc nng chng trnh son tho ca Step7 v c bn cng ging nh cc

chng trnh son tho khc, tc l cng c cc phm nng g nhanh, c ch

ct v dn, c ch kim tra li c php lnh.


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Hnh 3-14: Son tho chng trnh trong OB1

khai bo va son tho chng trnh cho cc khi OB khc hoc cho cc

khi FC, FB hoc DB, ta c th to mt khi mi ngay trc tip t chng trnh

son tho bng cch kch chut phi vo phn trng nhhnh v sau:

Hnh 3-15: M mt khi logic khc.

Phn Localblock cakhi OB1

Phn chthch cachngtrnh

Phn sonthochngtrnh


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Hoc cng c th chn thm khi mi trc t ca s chnh ca Step7

bng phm Insert -> S7 Block ri sau mi vo son tho chng trnh cho

khi mi c chn thm nh d lm vi OB1.

Trong mn hnh son tho chng trnh cho cc khi Logic, ta c th thay

i khng ring phn chng trnh m c phn local block ca khi bao gm

tn hnh thc, kiu d liu, gi tr ban u, Ch rng khng c thay i 20

bytes u trong local block ca cc khi OB.

Cc bc son tho mt khi logic cho chng trnh ng dng c tm tt

nh sau:

To khi logic hoc t ca s mn hnh chnh ca Step7 bng cch chnEinfuegen (Insert) trn thanh cng c ri vo S7 Block d chn loi khi

logic mong mun ( OB, FB, FC ) hoc vo chng trnh son tho ri t

kch biu tng New.

Thit k local block cho khi logic va to.Vi tt c cc khi hon thnh cng vic thit k Local Block ta cn phi ch

vic khai bo theo bng sau:

Loi bin ngha chc nng Khi thc hin

IN Nhn cc tn hiu t u vo c FB, FC

OUT Xut cc tn hiu ra xut FB, FC

IN_OUT Nhn v gi cc tn hiu c, xut FB, FCSTAT Ni dung ca bin hnh thc,

c kh nng lu gi li khi kt

thc chng trnh trong FB

c, xut FB

TEMP Bin tm thi, ni dung s b

mt i khi kt thc chng

trnh trong FB, FC hoc OB

c , xut FB, FC, OB

Son tho chng trnh: chng trnh c th c son tho theo rt nhiungn ng khc nhau v d: FBD, LAD, STL.... xem trong mc 2.2.


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2.Son tho mt chng trnh trong khi logic FC1:

Ta thc hin cc bc nh sau:

a/ To khi:

Hnh 3-16: To mt khi logic mi

Sau khi chn th mc nh hnh v trn trn mn hnh s hin ra mt ca s

sau:

Hnh 3-17: t tn v chn ch lm vic cho khi logic mi.


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Trong hp hi thoi cho php ta chn tn ca FC v d FC2. Trong thc t

Step7 lun mc nh th t ca cc FC v ta ch cn OK nu ta chp nhn tn

nh mc nh, ngoi ra ta cn c th chn ch vit chng trnh trong khi

hm FC2 di dng FBD, LAD hay STL. Cui cng ta nhn nt OK. Trn mn

hnh s xut hin ca s chnh ca Step7 nh sau:

Hnh 3-18: Gi mn hnh son tho.

son tho chng trnh trong FC2 ta ch cn nhy p chut tri vo biu

tng ca FC2 v lp tc s hin ra ca s son tho chng trnh cho FC2:

Hnh 3-19: Mn hnh son tho ca khi Logic FC2.

Nhy pphm trica chut vochngtrnh son

tho trongFC2


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b/ Xy dng Local block:

Trong ca s mn hnh son tho ta xy dng local block cho khi FC2 nh

sau:

Hnh 3-20: Nhp d liu vo khi Lokal block ca khi FC

c/ Son tho chng trnh:

Ton b chng trnh c th vit trong khi logic FC2 nh sau:

Hnh 3-21: Son tho chng trnh trong khi logic FC1.


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3.Son tho chng trnh cho khi FB.

a/To khi FB: Ta c th to khi FB bng cch t ca s mn hnh chnh ca

Step7 ta dng chut phi v chn cc i tng nhhnh sau:

Hnh 3-22: To khi FB

Sau khi chn th mcFunktionsblocktrn mn hnh xut hin mt ca s:

Trong ca s ta cn phi t tn cho khi FB m ta mi chn v d FB1

(thng thng S7 t gn cho mt tn theo th t m ngi lp trnh chn khi

nu ng ta ch cn nhn nt OK). Ngoi ra ta cn c th t tn cho khiFB; v d: test_1, chn cch vit chng trnh AWL, KOP, FUP hay S7-

GRAPH,..... Sau khi in cc thng tin vo ca s mn hnh ta nhn nt

OK.

Mun son tho chng trnh trong khi FB ta ch cn nhn p chut tri

vo biu tng FB trn mn hnh chnh. Sau khi thc hin xong bc ny ta s

c ca s son tho chng trnh cho khi FB1 v cng vic tip theo cng c

thc hin ging nh ta thc hin i vi khi FC trn , l cc bc nh

xy dng Local block, son tho chng trnh.


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Hnh 3-23: Chn ngn ng vit chng trnhtrong khi FB1

b/Th tc gi khi FB:

V khi FB bao gi cng lm vic vi khi d liu DB dng lu gi ni

dung cc bin kiu STAT ca Local block. V vy thc hin vic gi khi FB

ta phi t tn cho khi d liu DB tng ng. Lnh gi khi hm FB nh sau:

Hnh 3-24:Gi khi FB1


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Tu theo nhu cu s dng m ta s dng mt , hai hay nhiu khi DB ta phi

t tn cho khi DB m ta va chn v d DB1, DB2,...

Sau khi chn xong bc trn ta c th son tho chng trnh cho khi

DB1 v DB2 nh sau:

Hnh 3-25:Mn hnh son tho trong khi FBs.

3.4.5.S dng bin hnh thc:

Step7 cung cp mt kh nng s dng tn hnh thc trong lp trnh thay v

cc k hiu a ch , ch s khi FB, FC,...kh nh. Cc tn hnh thc c thay

bi mt a ch hay mt tn khi tu theo ngi lp trnh t t. lm c

iu ny, ngi lp trnh cn phi khai bo trc trong mt bng c tn lSymbols.

Kch chut vo th mc m ca Block, y l th mc vi tn mc nh l

S7 Program(1), sau nhy phm chut tri ti biu tng Symbole nh hnh v

ta s c mn hnh son tho bng cc tn hnh thc sau:


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Hnh3-26: S dng bin hnh thc.

Hnh 3-27: Ghi cc k hiu bin hnh thc vo bng Symbol.

Sau khi in y tn hnh thc, a ch nh m n thay th ( hu ht kiu

d liu u c S7 t xc nh cn c vo a ch nh) v ct vo Project, ta

s quay tr li mn hnh chnh ca S7. M mt khi chng trnh, v d OB1 v

chn biu tng dng bin hnh thc ta s chuyn sang dng son tho vi

nhng bin hnh thc nh t sn trong bng Symbole.


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v d :

Hnh 3-28: Mn hnh son tho vi cc tn bin hnh thc.

Mun quay tr v s dng li cc k hiu a ch tuyt i ta nhn li nt

chn ban u l biu tng ny nm trn thanh cng c .

3.5.Np chng trnh v gim st vic thc hin chng trnh.

3.5.1. Np chng trnh son tho t PC xung CPU:

Chng trnh sau khi son tho cn c truyn xung CPU. lm c

iu ny, ta nhn chut tri vo biu tng ny trn thanh cng c v tr

li y cc cu hi. Ch khi np chng trnh cn phi t CPU trng thi

Stophoc t CPU trng thiRUN-P.

3.5.2.Xo chng trnh c trong CPU:

thc hin vic np chng trnh mi t PC xung CPU ta cn thc hin

cng vic xo chng trnh c sn trong CPU. iu ny ta thc hin cc

bc nh sau:- a trng thi ca CPU v STOP : T mn hnh chnh ca Step7 ta chn

lnh:


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Hnh 3-29

3.5.3.Quan st vic thc hin chng trnh:

Sau khi np chng trnh son tho xung CPU lc ny chng trnh

c ghi vo b nh ca CPU. Khi ta c th tch ri PC v CPU ca S7 m

chng trnh vn hot ng bnh thng. thc hin vic quan st qu trnh

hot ng ca chng trnh v CPU ta s dng chc nng gim st chng trnh

bng cch nhn vo biu tng ny trn thanh cng c. Sau khi chn chc

nng gim st chng trnh ny th trn mn hnh s xut hin mt ca s sau:

Tu theo kiu vit chng trnh m ta nhn c s khc nhau v kiu hin

th trn mn hnh (Di y s dng kiu vit chng trnh FBD).


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Hnh 3-30: Quan st qu trnh hot ng.

Ngoi ra ta cn c th quan st c ni dung ca nh. Nhng nh mun

quan st cn phi khai bo trong bng Variable.

Hnh 3-31: Quan st ni dung ca nh.

Sau khi khai bo tt c cc bin cn quan st ta kch vo phm quan st trn

mn hnh xut hin ca s nh hnh trn. Tu theo yu cu m ta kch vo phm

quan st tng ng trn mn hnh s hin th ni dung ca nh ti thi im

hin ti hay lin tc quan st theo tng thi im.


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Chng 4. Cc hm c bn:

4.1.Nhm hm Logic tip im:

1/ Hm AND : Ton hng l kiu d liu BOOL hay a ch bit I,Q, M, T,

C, D, L

FBD LAD STL

Hnh 4-1: Cch khai bo hm AND

Tn hiu ra Q4.0 s bng 1 khi ng thi tn hiu I0.0=1 v I0.1=1.

D liu vo v ra :

Vo: I0.0, I0.1: BOOL

Ra : Q4.0 : BOOL

2/ Hm OR : Ton hng l kiu d liu BOOL hay a ch bit I,Q, M, T,

C, D, L.

FBD LAD STL

Hnh 4-2: Khai bo hm OR

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

D liu vo v ra:

Vo : I0.0, I0.1: BOOL

Ra : Q4.0: BOOL


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3/ Hm NOT:

FBD LAD STL

Hnh 4-3: Khai bo hm thc hin chc nng ph nh.

Tn hiu ra s l nghich o ca tn hiu vo.

D liu vo v ra:

Vo : I0.0 : BOOL

Ra : Q4.0 : BOOL

4/ Hm XOR: Ton hng l kiu d liu BOOL hay a ch bit I, Q, M, T,

C, D, L.

FBD LAD STL

Hnh 4-4: Khi thc hin chc nng XOR.

Tn hiu ra Q4.0= 1 khi I0.0 khc I0.2

D liu vo v ra:

Vo: I0.0, I0.1 : BOOL

Ra : Q4.0 : BOOL


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5/ Lnh xo RESET: Ton hng l a ch bit I, Q, M, T, C, D, L.

FBD LAD STL

Hnh 4-5: Khi thc hin chc nng RESET

Tn hiu ra Q4.0 = 0 (Q4.0 s c xo ) khi I0.0 =1 .

D liu vo v ra:

Vo: I0.0 : BOOL

Ra : Q4.0 : BOOL

6/ Lnh SET: Ton hng l a ch bit I, Q, M, T, C, D, L.

FBD LAD STL

Hnh 4-6: Khi thc hin chc nng SET.

Tn hiu ra Q4.0 = 1 (Q4.0 s c thit lp ) khi I0.0 =1.

D liu vo v ra:

Vo I0.0 : BOOL

Ra Q4.0 : BOOL


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7/B nh RS: Ton hng l a ch bit I, Q, M, D, L.

FBD LAD STL

Hnh 4-7: Khi thc hin chc nng RS.

Khi I0.0 = 1 v I0.1 =0 Merker M0.0 b Reset v u ra Q4.0 l "0". Nu

I0.0 = 0 v I0.1 = 1 th Set cho M0.0 v u ra Q4.0 l "1".

Khi c hai u vo Set va Reset cng ng thi =1 th M0.0 v Q4.0 c gi

tr l "1".

D liu vo v ra:Vo I0.0, I0.1 : BOOL

Ra Q4.0 : BOOL

8/ B nh SR: Ton hng l a ch bit I, Q, M, D, L

FBD LAD STL

Hnh 4-8: Khi thc hin chc nng SR

Khi I0.0 = 1 v I0.1 =0 th Set cho Merker M0.0 v u ra Q4.0 l "1". Nu

I0.0 = 0 v I0.0 = 1 th M0.0 b Reset v u ra Q4.0 l "0".

Khi c hai u vo Set va Reset cng ng thi =1 th M0.0 v Q4.0 c gi

tr l "0".D liu vo v ra:

Vo I0.0, I0.1 : BOOL

Ra Q4.0 : BOOL

Ch : Trong k thut s trng thi ca trig RS s b cm khi R=1 v S=1. Nn

y c hai loi b nh RS v SR l loi Trigu tin R hay u tin S


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4.2. Nhm hm so snh:

4.2.1.Nhm hm so snh s nguyn 16 bit:

FBD LAD STL

Hnh 4-9: Khi thc hin chc nng so snh bng nhau

C cc dng so snh hai s nguyn 16 bits nh sau :

Hm so snh bng nhau gia hai s nguyn 16 bits: == Hm so snh khc nhau gia hai s nguyn 16 bits: Hm so snh ln hn gia hai s nguyn 16 bits: > Hm so snh nh hn gia hai s nguyn 16 bits: < Hm so snh ln hn hoc bng nhau gia hai s nguyn 16 bits: >= Hm so snh nh hn hoc bng nhau gia hai s nguyn 16 bits:


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Hm so snh bng nhau gia hai s nguyn 32 bits: == Hm so snh khc nhau gia hai s nguyn 32 bits: Hm so snh ln hn gia hai s nguyn 32 bits: > Hm so snh nh hn gia hai s nguyn 32 bits: < Hm so snh ln hn hoc bng nhau gia hai s nguyn 32 bits: >= Hm so snh nh hn hoc bng nhau gia hai s nguyn 32 bits: Hm so snh nh hn gia hai s thc 32 bits: < Hm so snh ln hn hoc bng nhau gia hai s thc 32 bits: >= Hm so snh nh hn hoc bng nhau gia hai s thc 32bits:


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4.3.Cc hm ton hc:

4.3.1. Nhm hm lm vic vi s nguyn 16 bits:

1/ Cng hai s nguyn 16 bits:

FBD LAD STL

Hnh 3-12: Khi thc hin chc nng cng hai s nguyn 16 bits.

D liu vo v ra:EN: BOOL IN1: INT

IN2: INT OUT: INT ENO: BOOL

Khi tn hiu vo I0.0 = 1 u ra Q4.0 = 1 v hm s thc hin cng hai s

nguyn 16 bits MW0 vi MW2. Kt qu c ct vo MW10.

Trong trng hp tn hiu vo I0.0 = 0 u ra Q4.0 = 0 v hm s khng thchin chc nng.

2/ Tr hai s nguyn 16 bits:

FBD LAD STL

Hnh 4-13: Khi thc hin chc nng tr hai s nguyn 16 bits

D liu vo v ra:


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EN : BOOL IN1: INT

IN2: INT OUT: INT ENO: BOOLKhi tn hiu vo I0.0 = 1 u ra Q4.0 = 1 v hm s thc hin tr hai s


Trong trng hp tn hiu vo I0.0 = 0 u ra Q4.0 = 0 v hm s khng thc

hin chc nng.

3/ Nhn hai s nguyn 16 bits:

FBD LAD STL

Hnh 4-14: Khi thc hin chc nng nhn hai s 16 bits.

D liu vo v ra:

EN: BOOL IN1: INTIN2: INT OUT: IN ENO: BOOL

Khi tn hiu vo I0.0 = 1 u ra Q4.0 = 1 v hm s thc hin nhn hai s



hin chc nng.

4/ Chia hai s nguyn 16 bits:

FBD LAD STL


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Hnh 4-15: Khi thc hin chc nng chia hai s nguyn 16 bits

Khi tn hiu vo I0.0 = 1 u ra Q4.0 = 1 v hm s thc hin chia hai s



hin chc nng.

4.3.2.Nhm hm lm vic vi s nguyn 32 bits:

1/ Cng hai s nguyn 32 bits:

D liu vo v ra:EN: BOOL IN1: DINT

IN2: DINT OUT: DINT ENO: BOOL

FBD LAD STL

Hnh 4-16: Khi thc hin chc nng cng hai s nguyn 32 bits

Khi tn hiu vo I0.0 = 1 u ra Q4.0 = 1 v hm s thc hin cng hai snguyn 32 bits MD0 vi MD4. Kt qu c ct vo MD10.


hin chc nng.

2/ Tr hai s nguyn 32 bits:


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Khi tn hiu vo I0.0 = 1 u ra Q4.0 = 1 v hm s thc hin tr hai s

nguyn 32 bits MD0 vi MD4. Kt qu c ct vo MD10.


hin chc nng.

FBD LAD STL

Hnh 4-17: Khi thc hin chc nng tr hai s nguyn 32 bitsD liu vo v ra:EN: BOOL IN1: DINT

IN2: DIN OUT: DINT ENO: BOOL

3/ Nhn hai s nguyn 32 bits:




hin chc nng.FBD LAD STL

Hnh 4-18: Khi thc hin chc nng nhn hai s nguyn 32 bit


IN2: DINT OUT: DINT ENO: BOOL4/ Chia hai s nguyn 32 bits :


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hin chc nng.


IN2: DINT OUT: DINT ENO: BOOL

FBD LAD STL

Hnh 4-19: Khi thc hin chc nng chia hai s nguyn 32 bits

4.3.3.Nhm hm lm vic vi s thc:

1/ Cng hai s thc:

Khi tn hiu vo I0.0 = 1 u ra Q4.0 = 1 v hm s thc hin cng hai s

thc MD0 + MD4. Kt qu c ct vo MD10.


hin chc nng.

FBD LAD STL

Hnh 4-20: Khi thc hin chc nng cng hai s thc

D liu vo v ra:EN: BOOL IN1: REAL

IN2: REAL OUT: REAL ENO: BOOL


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2/ Hm tr hai s thc:

Khi tn hiu vo I0.0 = 1 u ra Q4.0 = 1 v hm s thc hin tr hai s thc

MD0 - MD4. Kt qu c ct vo MD10.


hin chc nng.

FBD LAD STL

Hnh 4-21: Khi thc hin chc nng tr hai s thc.



3/ Nhn hai s thc:


thc MD0 . MD4. Kt qu c ct vo MD10.

FBD LAD STL

Hnh 4-22: Khi thc hin chc nng nhn hai s thc.


hin chc nng.

D liu vo v ra:


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EN: BOOL IN1: REAL


4/ Chia hai s thc:


thc MD0 : MD4. Kt qu c ct vo MD10.

Trong trng hp tn hiu vo I0.0 = 0 u ra Q4.0 = 0 v hm s khng thchin chc nng.

FBD LAD STL

Hnh 4-23: Khi thc hin chc nng nhn hai s thc


IN2: REAL OUT: REAL

ENO: BOOL

5/ Hm ly gi tr tuyt i : ABS


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Khi tn hiu vo I0.0 = 1 u ra Q4.0 = 1 v hm s thc hin chc nng ly

ga tr tuyt i ca MD8 ri ct vo MD12

Khi tn hiu vao I0.0 = 0 u ra Q4.0 = 0 v hm s khng thc hin chc

nng.

FBD LAD STL

Hnh 4-24: Khi thc hin chc nng ly gi tr thuyt i.D liu vo v ra:EN: BOOL IN: REAL

OUT: REAL ENO: BOOL

V d: MD8= -6,234 x 10-3 thi sau khi thc hin chc nng ABS gi tr MD12 =

6,234 x 10-3.

6/ Hm SIN, COS, TAN, ASIN, ACOS, ATAN:

Khi tn hiu vo I0.0 = 1 u ra Q4.0 = 1 v hm s thc hin chc nng tinh

SIN, COS, TAN, ASIN, ACOS, ATAN ca MD0 ri ct vo MD10.Khi tn hiu vo I0.0 = 0 u ra Q4.0 = 0 v hm s khng thc hin chc nng.

FBD LAD STL

Hnh 4-25: Khi thc hin chc nng tnh hm Sin.

D liu vo v ra:EN: BOOL IN: REAL

OUT: REAL ENO: BOOL


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4.4.Nhm hm i kiu d liu :

Trong ngn ng lp trnh ca S7-300 c mt s kiu d liu khc nhau nh:

- S nguyn 16 bits (Interger)- S nguyn 32 bits (DI)

- S nguyn dng BCD.

- S thc REAL

- v mt s dng d liu khc .

Khi lm vic vi nhiu dng d liu khc nhau cho ta vn cn phi chuyn

i chng. V d khi c tn hiu t cng vo tng t ta nhn c s liu dng

nguyn 16 bits mang gi tr tn hiu tng t ch khng phi bn thn gi tr ,

bi vy x l tp th cn thit phi chuyn i s nguyn thnh ng gi

tr thc, du phy ng ca tn hiu tng t cng. Ta c mt s hm chuyn

i cc dng d liu nh sau:

4.4.1.Hm chuyn s BCD thnh s s nguyn 16 bits:

FBD LAD STL

Hnh 4-26: Chuyn i s BCD sang dng s nguyn 16 bits.

D liu vo v ra:EN: BOOL IN: WORD

OUT: INT ENO: BOOLKhi tn hiu vo I0.0 = 1 u ra Q4.0 = 1 v hm thc hin chc nng chuyn

s BCD (MW10) sang s nguyn ri ct vo MW12.

Khi tin hiu vo I0.0 = 0 u ra Q4.0 = 0 v hm khng thc hin chc nng

chuyn i.


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4.4.2. Hm chuyn i s nguyn 16 bits sang dng BCD.

FBD LAD STL

Hnh 4-27: Chuyn i s nguyn sang s BCD.

D liu vo v ra:EN: BOOL IN: INT

OUT: BCD ENO: BOOLKhi tn hiu vo I0.0 = 1 u ra Q4.0 = 1 v hm thc hin chc nng chuyn

s nguyn 16 bits (MW10) sang s BCD ri ct vo MW12.

Khi tin hiu vo I0.0 = 0 u ra Q4.0 = 0 v hm khng thc hin chc nng

chuyn i.

4.4.3. Hm chuyn i s nguyn 16 bits sang s nguyn 32 bits:

FBD LAD STL

Hnh 4-28: Chuyn i s nguyn 16 bits sang s nhuyn 32 bits.

D liu vo v ra:EN: BOOL IN: INT

OUT: DINT ENO: BOOL


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Khi tn hiu vo I0.0 = 1 u ra Q4.0 = 1 v hm thc hin chc nng chuyn

s nguyn 16 bits (MW10) sang s nguyn 32 bits ri ct vo MW12.

Khi tn hiu vo I0.0 = 0 u ra Q4.0 = 0 v hm khng thc hin chc nng

chuyn i.

4.4.4.Chuyn i s BCD sang s nguyn 32 bits:

Khi tn hiu vo I0.0 = 1 u ra Q4.0 = 1 v hm thc hin chc nng chuyn

s BCD (MW10) sang s nguyn 32 bits ri ct vo MW12.

Khi tn hiu vo I0.0 = 0 u ra Q4.0 = 0 v hm khng thc hin chc nng

chuyn i.

FBD LAD STL

Hnh 4-29: Chuyn s BCD sang s nguyn 32 bits

-Kiu d liu vo/ra:EN: BOOL IN: DWORD

OUT: DINT ENO: BOOL.

4.4.5.Hm o gi tr cc bits .

1/Vi s nguyn c di 16 bits:

-Nguyn l hot ng: Hm s thc hin chc nng chuyn i gi tr cc bitstrong MW8 ri ct vo MW10 khi tn hiu I0.0 =1. ng thi gi tr Q4.0 = 1.Khi I0.0 = 0, gi tr Q4.0 = 0-Kiu d liu vo/ra:EN: BOOL IN: INT

OUT: INT ENO: BOOL

FBD LAD STL


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Hnh 4-30: Hm thc hin chc nng o gi tr cc bits

-V d:

Trc khi thc hin

Sau khi thc hin

2/ Vi s nguyn c di 32 bits.

FBD LAD STL

Hnh 4-31: Hm thc hin chc nng o gi tr cc bits.

-Nguyn l hot ng: Hm s thc hin chc nng chuyn i gi tr cc bitstrong MD8 ri ct vo MD12 khi tn hiu I0.0 =1. ng thi gi tr Q4.0 = 1 .Khi I0.0 = 0, gi tr Q4.0 = 0-Kiu d liu vo/ra:

EN: BOOL IN: DINT

OUT: DINT ENO: BOOL

- V d:Trc khi thc hin: MD8 = F0FF FFF0Sau khi thc hin : MD12 = 0F00 000F

4.4.6.Cc hm i du :


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Hm s thc hin chc nng i du d liu vo . Cc hm i du nh i

du s thc di 16bits ( I ), 32 bits ( DI ) hay s nguyn ( R ).

FBD LAD STL

Hnh 4-32:

Dng d liu vo:

NEG_I NEG_DI NEG_R

EN BOOL BOOL BOOL

IN INT DI REAL

OUT INT DI REAL

ENO BOOL BOOL BOOL

V d: Trc khi thc hin MW8 = +10, sau khi thc hin MW10 = -10.

4.4.7.Cc hm thc hin chc nng lm trn (i kiu d liu):


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FBD LAD STL

Hnh 4-33:

-Hm ROUND : (chuyn s thc thnh s nguyn gn nht) thc hin lm trn

nh sau: nu phn l < 0,5 th lm trn xung. Nu phn l > 0,5 th lm trn

ln.

V d: 1,2 -> 1 ; 1,6 -> 2.-1,2 -> -1 ; -1,6 -> -2.

-Hm TRUNC: (ly phn nguyn ct b phn l) thc hin lm trn xung gi

tr trn nh

v d: d liu vo t 1,1 n 1,9 -> 1.


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-Hm CEIL: thc hin lm trn ln.

v d: d liu vo t 1,1 n 1,9 -> 2.

-Hm FLOOR: thc hin lm trn xung.

v d: +1,7 -> 1 ; - 1,7 -> -2

4.5.B thi gian:

4.5.1 Nguyn l lm vic chung ca b Timer.


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B thi gian Timer l b to thi gian tr T mong mun gia tn hiu logic

u vo X(t) v u ra Y(t)

S7-300 c 5 b thi gian Timer khc nhau. Tt c 5 loi Timer ny cng bt

u to thi gian tr tn hiu k t thi im c sn ln ca tn hiu u vo ,

tc l khi c tn hiu u vo U(t) chuyn trng thi t logic "0" ln logic"1",

c gi l thi im Timer c kch.

Thi gian tr T mong mun c khai bo vi Timer bng gi tr 16 bits bao

gm hai thnh phn :

- phn gii vi n v l mS. Timer ca S7 c 4 loi phn gii khc nhau l

10ms, 100ms, 1s v 10s.

- Mt s nguyn BCD trong khong t 0 n 999 c gi l PV ( Preset Value-

gi tr t trc).

Nh vy thi gian tr T mong mun s c tnh nh sau :

T= phn gii x PV.

Ngay ti thi im kch Timer, gi tr PV c chuyn vo thanh ghi 16 bits

ca Timer T-Word ( gi l thanh ghi CV- Curren value- gi tr tc thi). Timer

s ghi nh khong thi gian tri qua k t khi kch bng cch gim dn mt

cch tng ng ni dung thanh ghi CV. Nu ni dung thanh ghi CV tr v bng

0 th Timer t c thi gian mong mun T v iu ny c bo ra ngoi

bng cch thay i trng thi tn hiu u ra Y(t). Vic thng bo ra ngoi bng

cch i trng thi tn hiu du ra Y(t) nh th no cn ph thuc vo loi Timerc s dng.

Bn cnh sn ln ca tn hiu u vo U(t), Timer cn c th kch bng

sn ln ca tn hiu kch ch ng c tn l tn hiu ENABLE nu nh ti thi

im c sn ln ca tn hiu ENABLE, tn hiu u vo U(t) c gic l "1".

Timer

CV

U t

PV

Y t

T-bit

Hnh 4-34: S khi b thigian.


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Tng loi Timer c nh s t 0 n 255 (tu thuc vo tng loi CPU).

Mt Timer c t tn l Tx, trong x l s hiu ca Timer ( 0


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FBD LAD STL

Hnh 4-35: B thi gian SP.

-Nguyn l lm vic:

Ti thi im sn ln ca tn hiu vo SET thi gian s c tnh ng thi

gi tr Logic u ra l "1". Khi thi gian t kt thc gi tr u ra cng tr v0.

Tn hiu vo S

Tn hiu vo R

Thi gian t

u ra

u ra o

Hnh 4-36: Gin thi gian ca b to tr kiu SP.

Khi c tn hiu RESET (R) thi gian tnh lp tc tr v 0 v tn hiu u racng gi tr l "0".

-Trng hp khng s dng cc tn hiu u vo SET(S), RESET ( R), BI v

BCD ta s dng khi Timer SI sau:


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Tn hiu u vo I0.0 chnh l tn

hiu kch.

S5T#2s l thi gian t 2s

Tn hiu ra ca b thi gian tc

ng ti u ra Q4.0

Hnh 4-37: V d khai bo mt b thi gian SP

2.B thi gian SE.FBD LAD STL

Hnh 4-38:Khi hm thi gian SE

-Nguyn l lm vic:

Ti thi im sn ln ca tn hiu vo SET cui cng b thi gian c thit

lp v thi gian s c tnh ng thi gi tr Logic u ra l "1". Kt thc thi

gian t tn hiu u ra s tr v 0.

tn hiu vo S


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Tn hiu vo R

Thi gian t

u ra

u ra o

Hnh 4-39: Gin thi gian khi SE

Khi c tn hiu RESET (R) thi gian tnh lp tc tr v 0 v tn hiu u ra

cng gi tr l "0".

3.B thi gian SD.FBD LAD STL

Hnh 4-40: S khi hm SD.

-Nguyn l lm vic:

Ti thi im sn ln ca tn hiu vo SET b thi gian c thit lp v

thi gian s c tnh. Kt thc thi gian t tn hiu u ra s c gi tr l "1".

Khi tn hiu u vo kch S l "0" u ra cng lp tc tr v "0" ngha l tn hiu

u ra s khng c duy tr hi tn hiu kch c gi tr l "0".

tn hiu vo S


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Tn hiu vo R

Thi gian t

u ra

u ra o

Hnh 4-41: Gin thi gian SD.

Khi c tn hiu RESET (R) thi gian tnh lp tc tr v "0" v tn hiu u ra

cng gi tr l "0".


BCD ta s dng khi Timer SE sau:


hiu kch.



ng ti u ra Q4.0.

Hnh 4-42: v d s dng khi hm SD.

4.B thi gian SS:FBD LAD STL


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Hnh 4-43: Khai bo b thi gian SS.

Tn hiu vo S

Tn hiu vo R

Thi gian t

u ra

u ra o

Hnh 4-44: Gin thi gian hm SS.

-Nguyn l lm vic:

Ti thi im sn ln ca tn hiu vo SET b thi gian c thit lp v

thi gian s c tnh. Kt thc thi gian t tn hiu u ra s c gi tr 1 gi tr

ny vn duy tr ngay c khi tn hiu u vo kch S c gi tr l 0. Khi c tn hiu

RESET (R) thi gian tnh lp tc tr v 0 v tn hiu u ra cng gi tr l "0".

-Trng hp khng s dng cc tn hiu u vo SET(S), RESET (R), BI vBCD ta s dng khi Timer SS sau:


hiu kch.



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ng ti u ra Q4.0

Hnh 4-45: V d s dng khi hm SS

5.B thi gian SA:FBD LAD STL

Hnh 4-46: S khi.

-Nguyn l lm vic:

Ti thi im sn ln ca tn hiu vo SET b thi gian c thit lp. Tn

hiu u ra c gi tr l 1. Nhng thi gian s c tnh thi im sn xung

cui cng ca tn hiu u vao SET(S). Kt thc thi gian t tn hiu u ra s

tr v 0.

Tn hiu vo S

Tn hiu vo R


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Thi gian t

u ra

u ra o

Hnh 4-47: Gin thi gian.

Khi c tn hiu RESET (R) thi gian tnh lp tc tr v 0 v tn hiu u ra

cng gi tr l "0".


BCD ta s dng khi Timer SF sau:

Tn hiu I0.0 l tn hiu kch

Thi gian t S5T#2s l 2s

Hm thi gian s tc ng ti u ra Q4.0

Hnh 4-48: S dng hm SF.

4.6 B m COUNTER:

4.6.1.Nguyn l lm vic:


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Counter thc hin chc nng m ti cc sn ln ca cc xung u vo. S7-

300 c ti a l 256 b m ph thuc vo tng loi CPU, k hiu bi Cx. Trong

x l s nguyn trong khong t 0 n 255. Trong S7-300 c 3 loi b m

thng s dng nht l : B m tin li (CUD), b m tin (CU)v b m

li (CD).

Mt b m tng qut c th c m t nh sau:

trong :

CU : BOOL l tn hiu m tin

CD : BOOL l tn hiu m li

S : BOOL l tn hiu t

PV : WORD l gi tr t trc

R : BOOL l tn hiu xo

CV : WORD L gi tr m h m 16

CV_BCD: WORD l gi tr m h m BCD

Q : BOOL L tn hiu ra . Hnh 4-49: s khi b

m Counter

Qu trnh lm vic ca b m c m t nh sau:

S sn xung m c, c ghi vo thanh ghi 2 Byte ca b m, gi l thanh

ghi C-Word. Ni dung ca thanh ghi C-Word c gi l gi tr m tc thi

ca b m v k hiu bng CV v CV_BCD. B m bo trng thi ca C-

Word ra ngoi C-bit qua chn Q ca n. Nu CV 0 , C-bit c gi tr "1".

Ngc li khi CV = 0, C- bit nhn gi tr 0. CV lun l gi tr khng m. B m

s khng m li khi CV = 0.

i vi Counter, gi tr t trc PV ch c chuyn vo C-Word ti thi

im xut hin sn ln ca tn hiu t ti chn S.

B m s c xo tc thi bng tn hiu xo R (Reset). Khi b m c

xa c C-Word v C- bit u nhn gi tr 0.

4.6.2.Khai bo s dng:

Vic khai bo s dng mt Counter bao gm cc bc sau:


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B m s thc hin m tin ti cc sn ln ca tn hiu ti chn CU khi tnhiu I0.0 chuyn gi tr t "0" ln "1"

B m s m li ti cc sn ln ca tn hiu ti chn I0.1 khi tn hiuchuyn t "0" ln "1"

Gi tr ca b m s tr v 0 khi c tn hiu tai sn ln ca chn R ( I0.3)

2.B m tin : CUFBD LAD STL

Hnh 4-51: s khi b m tin.

-Nguyn l hot ng:Khi tn hiu I0.2 chuyn t "0" ln "1" b m c t gi tr l 55. Gi tr

u ra Q4.0 =1 .

B m s thc hin m tin ti cc sn ln ca tn hiu ti chn CU khitn hiu I0.0 chuyn gi tr t "0" ln "1"Gi tr ca b m s tr v 0 khi c tn hiu tai sn ln ca chn R (I0.3)B m s ch m n gi tr


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Hnh 4-52: S khi b m li.

-Nguyn l hot ng:Khi tn hiu I0.2 chuyn t "0" ln "1" b m c t gi tr l 55. Gi tr

u ra Q4.0 =1 .

B m s thc hin m li ti cc sn ln ca tn hiu ti chn CD khi tnhiu I0.0 chuyn gi tr t "0" ln"1"

Gi tr ca b m s tr v 0 khi c tn hiu tai sn ln ca chn R (I0.3).B m s ch m n gi tr >= 0.

4.7.Khi chuyn d liu:

FBD LAD STL

Hnh 4-53: S khi MOV

-Nguyn l hot ng:Khi c tn hu kch I0.0 khi Copy c thit lp , tn hiu u ra ENO l

Q4.0 =1. ng thi s liu u vo IN l MW0 c Copy sang u ra OUTl MW2.

Khi tn hiu kch I0.0 = 0 tn hiu u ra Q4.0 = 0.Trong trng hp mun thay i s liu trong b nh (tc l thay i gi tr

trong MW2) ta c th khng cn s dng tn hiu kch I0.0.


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4.8.Cc b ghi dch v quay s liu trn thanh ghi:

1.Dich phi s nguyn 16 bits:

FBD LAD STL

Hnh 4-54: S khi dch phi.

Hnh 4-55: Nguyn l hot ng.

Khi tn hiu kch I0.0 = 1 Khi s thc hin chc nng dich chuyn sang phi

s liu trong thanh ghi. ng thi tn hiu ra ti ENO l Q4.0 c gi tr l 1.

S liu a vo ti IN l MW0

S bit s dich chuyn l MW2 ( ti chn N).

Kt qu sau khi dch c ct vo MW4.

Trn s cho ta thy kt qu ca b dch phi 4 bit.

2.Dich phi s nguyn 32 bits:-S khi:

FBD LAD STL


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Hnh 4-56: Khi dch phi.

Khi tn hiu kch I0.0 = 1. Khi s thc hin chc nng dich chuyn sang

phi s liu trong thanh ghi. ng thi tn hiu ra ti ENO l Q4.0 c gi tr l

1.

S liu a vo ti IN l MD0

S bit s dch chuyn l MW2 (ti chn N). Kt qu sau khi dch c ct vo

MW4.Trn s cho ta thy kt qu ca b dch phi 4 bit.

3.Dich tri 16 bit:-S khi:

FBD LAD STL


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Hnh 4-57: Khi dch tri.

-Nguyn l hot ng:Khi c tn hiu kch I0.0 = 1 tn hiu ra Q4.0 c thit lp v c gi tr 1.

D liu u vo MW0 c dch sang tri vi s bit c t ti chn N(MW2).Kt qu sau khi dch c ghi vo MW4.

-Gin thi gian:

Hnh 4-58: Gin thi gian b dch tri 6 v tr.

Ch : Trong trng hp cn dich tri mt s 32 bits ta ch cn khai bo d

liu u vo IN di dng MD v d: MD0 v kt qu u ra cng s c lu

gi MD V d: MD4

4. Quay tri s 32 bits:-S khi:

FBD LAD STL


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Hnh 4-59: S khi quay tri.


D liu u vo MD0 c quay sang trI vi s bit c t ti chn N(MW4).

Kt qu sau khi dch c ghi vo MD10.

Hnh 4-60: Gin thi gian.

5. Quay phi s 32 bits:

-S khi:


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FBD LAD STL

Hnh 4-61: s khi b quay phi.


D liu u vo MD0 c quay phi vi s bit c t ti chn N (MW4).Kt qu sau khi dch c ghi vo MD10.

Hnh 4-62: Gin thi gian ca b dch phi 3 v tr s 32 bits.

4.9.Cc hm Logic thc hin trn thanh ghi :

1.Hm AND hai s c di l 16 bits.


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-S khi:

FBD LAD STL

Hnh 4-63: s dng khi AND 16 bits

-Nguynl hot ng:

Hm s thc hin chc nng nhn hai s nh phn tai u vo IN1 v u vo

IN2 kt qu c ct OUT ( MW2) khi c tn hiu kch ti chn EN (I0.0 =1).

Tn hiu u ra ENO (Q4.0 = 1) khi hm thc hin chc nng.

-V d:

IN1 = 0101010101010101 S th nht

IN2 = 0100000000001111 S th hai

OUT = 0100000000000101 Kt qu

2.Hm OR hai s c di l 16 bits:-S khi :


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FBD LAD STL

Hnh 4-64: S dng khi OR 16 bits.

-Nguyn l hot ng:

Hm s thc hin chc nng OR hai s nh phn tai u vo IN1 v u vo

IN2 kt qu c ct OUT ( MW2) khi c tn hiu kch ti chn EN (I0.0 = 1).

Tn hiu u ra ENO (Q4.0 = 1) khi hm thc hin chc nng.

-V d:

IN1 = 0101010101010101 S th nht

IN2 = 0000000000001111 S th Hai

OUT = 0101010101011111 Kt qu

3.Hm XOR hai s c di 16 bits:


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-S khi:

FBD LAD STL

Hnh 4-65: s khi XOR 16 bits.

-Nguynl hot ng:

Hm s thc hin chc nng XOR hai s nh phn tai u vo IN1 v u vo

IN2 kt qu c ct OUT khi c tn hiu kch ti chn EN.

Tn hiu u ra ENO khi hm thc hin chc nng.-V d:

IN1 = 0101010101010101 S th nht

IN2 = 0000000000001111 S th Hai

OUT = 0101010101011010 Kt qu

4.Hm AND hai t kp:

-S khi:

FBD LAD STL

Hnh 4-66: S dng khi AND hai t kp .

EN(I0.0): BOOL - tn hiu kchIN1: DWORD - Vo 1IN2: DWORD - vo2OUT: DWORD - RaENO: BOOL - Tn hiu ra ca khi.


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-Nguyn l hot ng:

Hm s thc hin chc nng AND hai s nh phn ti u vo IN1 v u vo


Tn hiu u ra ENO khi hm thc hin chc nng.

-V d:

IN1 = 0101010101010101 0101010101010101

IN2 = 0000000000000000 0000111111111111

OUT = 0000000000000000 0000010101010101

5.Hm OR hai t kp:

-S khi:

FBD LAD STL

Hnh 4-67: S dng khi OR hai t kp.


-Nguyn l hot ng:Hm s thc hin chc nng OR hai s c di 2 t ti u vo IN1 v u vo



-V d:

IN1 = 0101010101010101 0101010101010101


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IN2 = 0000000000000000 0000111111111111

OUT = 0101010101010101 0101111111111111

6.Hm XOR hai t kp :

-s nguyn l:

FBD LAD STL

Hnh 4-68: S dng khi XOR hai t kp.

-Nguyn l hot ng:

Hm s thc hin chc nng XOR hai s c di 2 t ti u vo IN1 v uvo IN2 kt qu c ct OUT khi c tn hiu kch ti chn EN.


-V d:

IN1 = 0101010101010101 0101010101010101

IN2 = 0000000000000000 0000111111111111

OUT = 0101010101010101 0101101010101010



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Ti liu tham kho

1.T ng ho vi Simatic S7-200. Nh xut bn nng nghip,1997- Don

Minh Phc, Phan Xun Minh.

2.S5-95U v phn mm Step5. Gio trnh ging dy ca trung tm o toSimens t ng ho trng HBK H ni, 1997- Don Minh Phc, Phan

Xun Minh.

3.SPS-Grundkurs, Volgel Buchverlag- Juergen Kaftan.

4.Speicherprogrammierte Steuerungen Aufgaben mit Loesungen, Europa-

Fachbuchreihe.

5.T ng ho vi Simatic S7-300. Nh xut bn khoa hc v k thut,

2000-Don Minh Phc, Phan Xun Minh, V Vn H .

tailieuPLC S7 300

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