chương 2 - các khái niệm plc

N HC PHN 2A GVHD: ThS HONG NH KHI

CHNG 2: CC KHI NIM V PLC Trang 2 - 1

Chng 2

Cc khi nim v PLC

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2.1. S thc thi chng trnh ngi dng.

CPU h tr cc kiu khi m sau y, cho php ta to ra mt cu trc hiu qu

cho chng trnh ngi dng:

Khi t chc (OB) xc nh cu trc chng trnh. Mt vi OB c trng thi v

cc s kin khi ng c thit lp trc, nhng ta cng c th to ra cc OB

vi cc s kin khi ng ty chnh.

Hm (FC) v khi hm (FB) cha m chng trnh tng ng vi cc nhim v

ring bit hay vi s kt hp cc thng s. Mi FC v FB cung cp mt t hp

cc thng s ng vo v ng ra dnh cho vic chia s d liu vi khi ang gi.

FB cng s dng mt khi d liu ( gi mt DB tc thi) c lin quan duy

tr trng thi ca cc gi tr gia s thc thi m c th c s dng bi cc

khi khc trong chng trnh.

Khi d liu (DB) lu tr d liu m c th c s dng bi cc khi chng

trnh.

S thc thi chng trnh ngi dng bt u vi mt hay nhiu hn cc khi t

chc (OB) khi ng ty chn, c thc thi mt ln trong lc i vo ch RUN, v

c theo sau bi mt hay nhiu hn cc OB chu k chng trnh c thc thi mt

cch tun hon. OB cng c th kt hp vi mt s kin ngt, c th l mt s kin

ngt tiu chun hay mt s kin li, v thc thi khi no m s kin tiu chun hay s

kin li tng ng xut hin.

Hm (FC) hay khi hm (FB) l mt khi m chng trnh m c th c gi

t mt OB hay t mt FC hay FB khc, xung n cc cp sau y:

16 t OB chu k chng trnh hay OB khi ng

4 t OB ngt tr hon thi gian, OB ngt theo chu trnh, OB ngt phn cng,

OB ngt li thi gian, hay OB ngt li chn on.

FC khng lin kt vi bt k phn no ca khi d liu (DB), trong khi FB

c gn kt mt cch trc tip n mt DB v s dng DB chuyn tip cc thng

s v lu tr cc gi tr v cc kt qu tm thi.




Kch thc ca chng trnh ngi dng, ca d liu v ca s cu hnh c

gii hn bi b nh np c sn v b nh lm vic trong CPU. Khng c gii hn no

i vi s lng cc khi c h tr bn trong lng b nh lm vic c sn.

Mi chu k bao gm vic ghi cc ng ra, vic c cc ng vo, vic thc thi cc

lnh ca chng trnh ngi dng, v vic thc hin bo tr h thng hay tin trnh x

l nn sau. Chu k c ni n nh l mt chu k qut hay mt ln qut.

Bng tn hiu, cc module tn hiu v cc module truyn thng c nhn bit

v c ghi li ch trong khi ngun c bt.

Lu

Vic lp vo v tho ra mt bng tn hiu, cc module tn hiu v module truyn thng

khi c ngun (thao tc nng) th khng c h tr. Ch mt ngoi l l th nh

SIMATIC, c th c lp vo hay ly ra trong khi CPU ang c cp ngun.

Di cu hnh mc nh, tt c cc im I/O kiu s v kiu tng t c cp

nht mt cch ng b vi chu k qut bng cch s dng mt vng nh bn trong

c gi l nh tin trnh. nh tin trnh cha mt s chp nhanh cc ng vo v ng

ra vt l (cc im I/O trn CPU, trn bng tn hiu v trn cc module tn hiu).

CPU thc hin cc tc v sau y:

CPU ghi cc ng ra t vng ng ra nh tin trnh n cc ng ra vt l.

CPU c cc ng vo ch u tin cho s thc thi chng trnh ngi dng v

lu tr cc gi tr ng vo trong vng ng vo nh tin trnh. iu ny m bo

rng cc gi tr ny s vn gi nguyn tnh nht qun trong sut s thc thi ca

cc lnh ngi dng.

CPU thc thi logic ca cc lnh ngi dng v cp nht cc gi tr ng ra trong

vng ng ra nh tin trnh thay v ghi n cc ng ra vt l thc t.




Chu trnh ny cung cp logic nht qun xuyn sut s thc thi ca cc lnh

ngi dng i vi trong mt chu k cho v ngn chn s chp chn ca cc im

ng ra, iu m c th thay i trng thi nhiu ln trong vng ng ra nh tin trnh.

Ta c th ch nh khi no cc im I/O kiu s v kiu tng t c lu tr

trong nh tin trnh. Nu ta chn vo mt module trong kiu xem thit b, d liu ca

n c t trong nh tin trnh ca CPU S7-1200 (mc nh). CPU thc thi s thay

i d liu gia module v vng nh tin trnh mt cch t ng trong sut vic cp

nht ca nh tin trnh. g b cc im kiu s hay kiu tng t ra khi s cp

nht t ng nh tin trnh, ta la chn thit b tng ng trong Device configuration,

xem th Properties, m rng nu cn t cc im I/O mong mun, v sau la

chn IO addresses/HW identifier. Sau thay i mc nhp cho Process image:

t Cyclic PI sang ---. thm cc im tr li s cp nht t ng nh tin trnh,

thay i mc la chn ny tr v Cyclic PI.

Ta c th c cc gi tr ng vo v ghi cc gi tr ng ra ngay lp tc khi mt

lnh thc thi. Mt ln c tc thi s truy xut n trng thi hin thi ca ng vo vt

l v khng cp nht vng ng vo nh tin trnh, bt chp d cho mt im c cu

hnh c lu tr trong nh tin trnh. Mt ln ghi tc thi n ng ra vt l s cp

nht c vng ng ra nh tin trnh (nu mt im c cu hnh c lu tr trong

nh tin trnh) v im ng ra vt l. Ta ni thm hu t :P vo a ch I/O nu mun

chng trnh truy xut ngay lp tc d liu I/O mt cch trc tip t im vt l thay

v s dng nh tin trnh.

Cu hnh cc thng s khi ng

Ta s dng cc thuc tnh ca CPU cu hnh cch thc CPU khi ng sau

mt chu k cp ngun.

La chn khi no CPU khi ng trong

ch STOP, ch RUN, hay trong

ch trc (u tin chu k cp

ngun).




CPU thc hin mt s khi ng li nng trc khi i vo ch RUN. S

khi ng li nng s t li ton b cc b nh gi li v cc gi tr khi ng mc

nh, nhng vn gi nguyn cc gi tr hin thi c lu tr trong b nh gi li.

Lu

CPU lun lun thc hin mt s khi ng li sau mt vic ti xung

Khi ta ti xung mt phn t ca n (nh mt khi chng tnh, mt khi d

liu hay cu hnh phn cng), CPU thc hin mt s khi ng li trong ln chuyn

tip k tip sang ch RUN. Ngoi vic xa i cc ng vo, khi chy cc ng ra v

khi chy b nh khng c kh nng gi li, s khi ng li cn khi kch hot cc

vng nh c kh nng gi li.

Sau mt khi ng li theo sau s ti xung, tt c cc chuyn i STOP sang

RUN tun t cng s thc hin mt s khi ng li nng (m khng kch hot b nh

c kh nng gi).




2.1.1. Cc ch hot ng ca CPU.

CPU c 3 ch hot ng: ch STOP, ch STARTUP v ch RUN.

Cc LED trng thi trn mt trc ca CPU biu th ch hin thi ca s vn hnh.

Trong ch STOP, CPU khng thc thi chng trnh no, v ta c th ti

xung mt n.

Trong ch STARTUP, cc OB khi ng (nu c) c thc thi mt ln.

Cc s kin ngt khng c x l cho n pha khi ng ca ch RUN.

Trong ch RUN, chu k qut c thc thi mt cch lp li. Cc s kin

ngt c th xut hin v c thc thi ti bt k im no nm trong pha chu k

chng trnh.

Ta khng th ti xung mt n trong khi ang ch RUN.

CPU h tr mt s khi ng li nng i vo ch RUN. Khi ng li

nng khng bao gm mt s t li b nh. Tt c cc h thng khng c kh nng gi

v d liu ngi dng u c khi chy ti mt s khi ng li nng. D liu

ngi dng c kh nng gi vn c gi nguyn.

Mt b nh t li s xa tt c cc b nh lm vic, xa cc vng nh c kh

nng gi v khng c kh nng gi, v sao chp b nh np n b nh lm vic. Mt

s t li b nh khng xa i b m chn on hay cc gi tr c lu vnh vin

ca a ch IP.

Ta c th ch nh ch bt ngun ca CPU hon thnh vi phng php khi

ng li bng cch s dng phn mm lp trnh. Biu tng cu hnh ny xut hin

trong mc Device Configuration i vi CPU ang trong khi ng. Khi ngun c

bt, CPU thc hin mt tun t cc kim tra chn on bt ngun v khi chy h

thng. CPU sau s i vo ch bt ngun tng ng. Tt nhin cc li c pht

hin s ngn khng cho CPU i vo ch RUN. CPU h tr cc ch bt ngun

sau y:

Ch STOP

Chuyn sang ch RUN sau mt s khi ng li nng




Chuyn sang ch trc sau mt s khi ng li nng

Ta c th thay i ch vn hnh hin thi bng cch s dng cc lnh

STOP hay RUN t cc cng c trc tuyn ca phn mm lp trnh. Ta cng c th

bao gm mt lnh STP trong chng trnh chuyn CPU v ch STOP. iu ny

cho php ta dng s thc thi chng trnh da trn logic lp trnh.

Trong ch STOP, CPU x l bt k cc

yu cu truyn thng no (thch hp) v thc hin t

chn on.

Trong ch STOP, CPU khng thc thi chng trnh ngi dng, v cc cp

nht t ng ca nh tin trnh s khng xut hin.

Ta c th ti xung ch khi CPU trong ch STOP.

Trong ch RUN, CPU thc hin cc tc v c th hin nh trong hnh sau

y:




STARTUP

A Xa vng nh I.

B Khi chy cc ng ra c vi gi tr cui cng hay gi tr thay th.

C Thc thi cc OB khi ng.

D Sao chp trng thi ca cc ng vo vt l n vng nh I.

E Lu tr bt k cc s kin ngt no vo trong th t x l trong ch RUN.

F Kch hot vic ghi vng nh Q n cc ng ra vt l.

RUN

Ghi b nh Q n cc ng ra vt l.

Sao chp trng thi cc ng vo vt l n vng nh I.

Thc thi cc OB chu k chng trnh.

Thc hin cc chn on t kim tra.

X l cc ngt v truyn thng trong sut bt k phn no ca chu k qut.




Tin trnh khi ng (STARTUP)

Khi trng thi hot ng thay i t STOP sang RUN, CPU xa i cc ng vo

nh tin trnh, khi chy cc ng ra nh tin trnh v thc thi cc OB khi ng. Bt

k vic c no truy xut n cc ng vo nh tin trnh bng cc lnh trong cc OB

khi ng s c gi tr zero hn l gi tr ng vo vt l hin thi. Do vy, c

trng thi hin thi ca mt ng vo vt l trong sut ch khi ng, ta phi thc

hin mt vic c tc thi. Cc OB khi ng v bt k cc FC v FB no c lin

quan s c thc thi tip theo. Nu c nhiu hn 1 OB khi ng tn ti, mi OB

s c thc thi theo th t s hiu OB, trong s hiu OB thp nht c thc thi

u tin.

Mi OB khi ng bao gm thng tin khi ng gip ta xc nh tnh hp l

ca cc d liu lu gi v ca ng h gi trong ngy. Ta c th lp trnh cc lnh bn

trong cc OB khi ng kim tra cc gi tr khi ng ny v thc hin thao tc

thch hp. Cc vng khi ng sau y c h tr bi cc OB khi ng:

Ng vo Kiu d liu Miu t

LostRetentive Bool Bit ny ng nu cc vng lu tr d liu gi b mt

LostRTC Bool Bit ny ng nu ng h gi trong ngy (Real time

Clock) b mt

CPU cn thc hin cc tc v sau y trong sut qu trnh khi ng:

Cc ngt c sp th t nhng khng c thc thi trong sut pha khi ng

Khng c vic gim st thi gian chu trnh no c thc hin trong sut pha

khi ng

S cu hnh lm thay i cc module HSC, PWM v PtP u c th c thc

hin trong lc khi ng

S vn hnh thc t ca cc module HSC, PWM v PtP ch xut hin trong ch

RUN




Sau khi s thc thi ca cc OB khi ng hon thnh, CPU i vo ch

RUN v thc thi cc tc v iu khin trong mt chu k qut lin tip.

Vic thc thi chu k qut trong sut ch RUN

i vi mi chu k qut, CPU ghi cc ng ra, c cc ng vo, thc thi chng

trnh ngi dng, cp nht cc module truyn thng, thc hin cc cng vic ni dch

(housekeeping) v p ng n cc s kin ngt ca ngi dng v cc yu cu truyn

thng. Cc yu cu truyn thng c x l mt cch nh k xuyn sut qu trnh

qut.

Cc hot ng ny (ngoi tr cc s kin ngt ca ngi dng) c thc hin

thng xuyn v theo mt trt t tun t. Cc s kin ngt ca ngi dng c kch

hot s c phc v vi mc u tin theo trt t m chng xut hin.

H thng m bo rng chu k qut s c hon tt trong mt chu k thi gian

c gi l thi gian chu trnh ti a, nu khng mt s kin li thi gian s c sinh

ra.

Mi chu k qut bt u bng vic tm kim cc gi tr hin thi ca cc ng ra

kiu s hay kiu tng t t nh tin trnh v sau ghi chng n cc ng ra

vt l ca CPU, cc module SB v SM c cu hnh cho vic cp nht I/O t

ng (cu hnh mc nh). Khi mt ng ra vt l c truy xut bi mt lnh,

c nh tin trnh ng ra v bn thn ng ra vt l u c cp nht.

Chu k qut tip tc bng vic c cc gi tr hin thi ca cc ng vo kiu s

hay kiu tng t t CPU, cc module SB, SM c cu hnh cho vic cp nht

I/O t ng (cu hnh mc nh), v sau ghi cc gi tr ny n nh tin

trnh. Khi mt ng vo vt l c truy xut bi mt lnh, gi tr ca ng vo

vt l c truy xut, nhng nh tin trnh ng vo khng c cp nht.

Sau khi c cc ng vo, chng trnh ngi dng c thc thi t lnh u

tin cho n lnh cui cng. iu ny bao gm tt c cc OB chu k chng

trnh cng vi tt c cc FC v FB c lin quan ca chng. Cc OB chu k

chng tnh c thc thi theo trt t ca s hiu OB, trong s hiu OB thp

nht c thc thi trc tin.




Vic x l cc truyn thng xut hin mt cch nh k trong sut qu trnh

qut, c th ngt s thc thi chng trnh ngi dng.

Cc kim tra t chn on bao gm c cc kim tra nh k ca h thng v cc

kim tra trng thi module I/O.

Cc ngt c th xut hin trong sut bt k phn no ca chu k qut, v c

iu khin theo s kin. Khi mt s kin xut hin, CPU ngt chu k qut v gi OB

c cu hnh thc thi s kin . Sau khi OB hon thnh vic thc thi s kin,

CPU khi phc li s thc thi ca chng trnh ngi dng ti im ngt.

Khi t chc (OB)

Cc OB iu khin s thc thi ca chng trnh ngi dng. Mi OB phi c

mt s hiu OB duy nht. Mt s s hiu OB mc nh c o ngc di gi tr

200. Cc OB khc phi c nh s t 200 hay ln hn.

Cc s kin ring bit trong CPU kch hot s thc thi ca mt khi t chc.

Cc OB khng th gi ln nhau hay c gi t mt FC hay FB. Ch c mt s kin

khi ng, nh l mt ngt chn on hay mt khong cch thi gian, l c th khi

ng s thc thi ca mt OB. CPU x l cc OB theo cc lp u tin tng ng ca

chng, trong cc OB c mc u tin cao hn c x l trc cc OB c mc u

tin thp hn. Lp u tin thp nht l 1 (i vi chu k chng trnh chnh), v lp

u tin cao nht l 27 (i vi cc ngt li thi gian).

OB iu khin cc s vn hnh sau y:

Cc OB chu k chng trnh thc thi mt cch tun hon trong khi CPU ang

ch RUN. Khi chnh ca chng trnh l mt OB chu k chng trnh. y

l ni m ta t cc lnh iu khin chng trnh v cng l ni ta gi cc khi

ngi dng b sung. Nhiu OB chu k chng trnh c cho php v c

thc thi theo th t bng s. OB 1 l mc nh. Cc OB chu k chng trnh

khc phi c nhn dng l OB 200 hay ln hn.

Cc OB tr hon thi gian thc thi ti mt khong thi gian dng c xc nh

sau mt s kin, c cu hnh hnh bi lnh ngt khi ng (SRT_DINT).

Thi gian tr hon c xc nh trong thng s ng vo ca lnh m rng




SRT_DINT. Mt OB tr hon thi gian ngt s thc thi chng trnh theo chu

trnh chun khi mt thi gian tr hon c nh trc tri qua. Ta c th cu

hnh ti a 4 s kin ngt tr hon thi gian ti bt k thi gian no cho, vi

mt OB c cho php cho mi s kin tr hon thi gian c cu hnh. OB tr

hon thi gian phi l t OB 200 tr ln.

Cc OB ngt theo chu trnh thc thi ti mi khong thi gian dng c xc

nh. Chng s ngt s thc thi chng trnh theo chu trnh ti khong thi gian

do ngi dng nh trc, v d nh mi 2 giy. Ta c th cu hnh ti a 4 s

kin ngt theo chu trnh, vi mt OB c cho php cho mi s kin ngt theo

chu trnh c cu hnh. OB ny phi l OB 200 tr ln.

Cc OB ngt phn cng thc thi khi s kin phn cng c lin quan xut hin,

bao gm cc ngng tng v gim trn cc ng vo s tch hp v cc s kin

HSC. Mt OB ngt phn cng s ngt s thc thi chng trnh theo chu trnh

chun theo phn ng n mt tn hiu t s kin phn cng. Ta xc nh cc s

kin trong cc thuc tnh ca cu hinh phn cng. Mt OB c cho php cho

mi s kin phn cng c cu hnh. OB ny phi l OB 200 tr ln.

Cc OB ngt li thi gian thc thi ki mt li thi gian c pht hin. Mt OB

ngt li thi gian s ngt s thc thi chng trnh theo chu trnh chun nu thi

gian chu trnh ti a b vt qu. Thi gian chu trnh ti a c xc nh

trong cc thuc tnh ca PLC. Ch c OB 80 l OB c h tr cho cc s kin

li thi gian. Ta c th cu hnh thao tc thc hin khi khng c mt OB 80:

hoc b qua li hoc chuyn v STOP.

Cc OB ngt li chn on thc thi khi mt li chn on c pht hin v

c bo co li. Mt OB chn on s ngt s thc thi chng trnh theo chu

trnh chun nu mt module c kh nng chn on pht hin ra mt li (nu s

ngt li chn on c khi ng cho module). Ch c OB 82 l OB c

h tr cho s kin li chn on. Nu khng c OB chn on no trong

chng trnh, ta c th cu hnh CPU hoc b qua li hoc chuyn v STOP.




2.1.2. Cc mc u tin v s sp xp vic thc thi s kin.

Vic x l ca CPU c iu khin bi cc s kin. Cc s kin kch hot cc

OB ngt c thc thi. OB ngt cho mt s kin c xc nh trong sut qu trnh

to ra khi, trong mc Device Configuration hay vi mt lnh ATTACH hoc

DETACH. Mt s s kin xy ra trn mt nn tng c h thng ging nh chu k

chng trnh hay cc s kin theo chu trnh. Cc s kin khc ch xy ra trong mt

thi gian ngn, ging nh s kin khi ng v cc s kin tr hon thi gian. Mt s

s kin xy ra khi c mt s thay i c kch hot bi phn cng, v d nh mt s

kin ngng trn mt im ng vo hay mt s kin b m tc cao. Ngoi ra cn

c cc s kin nh s kin li chn on v s kin li thi gian ch xy ra khi c mt

li. Cc mc u tin s kin, cc nhm v th t u tin c s dng xc nh trt

t x l i vi cc OB ngt s kin.

S kin chu k chng trnh xy ra mt ln trong sut mi chu k chng trnh

(hay chu k qut). Trong sut chu k chng trnh, CPU ghi cc ng ra, c cc ng

vo v thc thi cc OB chu k chng trnh. S kin chu k chng trnh l cn thit

v lun lun c kch hot. Ta c th khng c cc OB chu k chng trnh, hoc c

nhiu OB c la chn cho mi s kin chu k chng trnh. Sau khi s kin chu k

chng trnh c kch hot, OB chu k chng trnh c nh s thp nht (thng

l OB 1) s c thc thi. Cc OB chu k chng trnh khc c thc thi mt cch

tun t, theo trt t c nh s, ch trong chu k chng trnh.

Cc s kin ngt theo chu trnh cho php ta cu hnh s thc thi ca mt OB

ngt ti mt khong thi gian c cu hnh. Khong thi gian c cu hnh khi OB

c to ra v c la chn tr thanh mt OB ngt theo chu trnh. Cc s kin

theo chu trnh s ngt chu k chng trnh v thc thi OB ngt theo chu trnh (s kin

theo chu trnh nm nhm mc u tin cao hn so vi s kin chu k chng trnh).

Ch mt OB ngt theo chu trnh l c th c gn km n mt s kin theo chu

trnh. CPU h tr 4 s kin ngt theo chu trnh. Cc OB ngt theo chu trnh c mt

thuc tnh dch chuyn pha, v vy s thc thi ca cc ngt theo chu trnh trong chu k

thi gian ging nhau c th c dch chnh t mt thi gian khc bi mt dch

chnh pha.




S kin khi ng xy ra mt ln trn s chuyn i t STOP sang RUN v

lm cho OB khi ng c thc thi. Nhiu OB c th c la chn cho s kin khi

ng. Cc OB khi ng c thc thi theo th t nh s.

Cc s kin ngt tr hon thi gian cho php ta cu hnh s thc thi ca mt OB

ngt sau khi mt thi gian tr hon tri qua. Thi gian tr hon c xc nh vi

lnh SRT_DINT. Cc s kin tr hon thi gian s ngt chu k chng trnh thc

thi OB ngt tr hon thi gian. Ch c mt OB ngt tr hon thi gian l c th c

gn km vo mt s kin tr hon thi gian. CPU h tr 4 s kin tr hon thi gian.

Cc s kin ngt phn cng c kch hot bi mt s thay i trong phn

cng, v d mt ngng tng hay ngng gim trn mt im ng vo, hay mt s

kin HSC. C th c mt OB ngt c la chn cho mi s kin ngt phn cng. Cc

s kin phn cng c cho php trong phn Device configuration. Cc OB c xc

nh cho s kin trong Device configuration hay vi mt lnh ATTACH trong chng

trnh ngi dng. CPU h tr mt s s kin ngt phn cng. Cc s kin chnh xc

c da trn kiu CPU v s lng cc im ng vo.

Cc s kin ngt li chn on v ngt li thi gian c kch hot khi CPU

pht hin mt li. Cc s kin ny nm nhm mc u tin cao hn so vi cc s kin

ngt khc v c th ngt s thc thi ca cc s kin tr ngt phn cng, ngt theo chu

trnh v ngt tr hon thi gian. Mt OB ngt c th c xc nh cho mi s kin

trong cc s kin ngt li chn on v ngt li thi gian.

Nhn bit cc mc u tin v xp hng thc thi s kin

S lng cc s kin ch (xp hng) t mt ngun n l c gii hn bng

cch s dng mt hng khc cho mi kiu s kin. Di s t n gii hn ca cc s

kin ch i vi mt kiu s kin cho, s kin tip theo s b mt.

Mi s kin CPU c mt mc u tin lin quan, v cc mc u tin c phn

loi vo trong cc nhm u tin. Bng sau y tm lc cc su xp hng, cc

nhm u tin v cc mc u tin cho cc s kin CPU c h tr.




Lu

Ta khng th thay i vic gn mc u tin hay nhm u tin v su xp hng

Thng thng, cc s kin c phc v theo th t mc u tin (mc u tin

cao nht trc tin). Cc s kin c cng mc u tin s c phc v trn c s n

trc, phc v trc.

Kiu s kin

(OB) S lng

Cc s hiu OB

hp l

su

xp hng

Nhm

u tin

Mc

u tin

Program

cycle

1 chu k chng trnh

Nhiu OB c cho php

1 (mc nh)

200 hay ln hn 1 1

1

Startup 1 s kin khi ng 1

Nhiu OB c cho php

100 (mc nh)

200 hay ln hn 1 1

Time Delay 4 s kin tr hon thi gian

1 OB cho mi s kin 200 hay ln hn 8 2

3

Cyclic 4 s kin theo chu trnh

1 OB cho mi s kin 200 hay ln hn 8 4

Edges

16 s kin ngng tng

16 s kin ngng gim

1 OB cho mi s kin

200 hay ln hn 32 5

HSC

6 s kin CV = PV

6 s kin mnh lnh thay

i

6 s kin t li bn ngoi

1 OB cho mi s kin

200 hay ln hn 16 6

Diagnostic

Error 1 s kin Ch 82 8 9

S kin Time

Error/ S

kin

MaxCycle

time

1 s kin li thi gian

1 s kin thi gian

MaxCycle

Ch 82 8 3 26




S kin

2xMaxCycle

time

1 s kin 2xMaxCycle

time

Khng c OB

c gi - 3 27

1 Cc trng hp c bit i vi s kin khi ng:

S kin khi ng v s kin chu k chng trnh s khng bao gi xut hin ti cng

mt thi im v s kin khi ng s hon thnh trc khi s kin chu k chng trnh

c bt u (iu ny c iu khin bi h iu hnh).

Khng c s kin no c cho php ngt s kin khi ng. Cc s kin xut hin

trong sut s kin khi ng thay vo c xp hng x l sau, sau khi s kin

khi ng c hon tt.

Sau khi s thc thi ca mt OB bt u, vic x l OB khng th b ngt

bng s xut hin ca mt s kin khc t cng mt nhm u tin hay thp hn. Cc

s kin no c xp hng x l sau s cho php OB hin thi hon tt.

Tuy nhin, s kin t mt nhm u tin cao hn s ngt OB hin thi, v CPU

sau s thc thi OB ca s kin c mc u tin cao hn. Sau khi OB c mc u tin

cao hn hon tt, CPU thc thi cc OB ca cc s kin khc c xp hng trong

nhm u tin cao ny, da trn mc u tin nm trong nhm . Khi khng c s kin

no ang ch (xp hng) trong nhm u tin cao hn ny, CPU s tr li n nhm u

tin thp hn v khi phc li vic x l ca OB b xa rng trc, ti im m

vic x l ca OB b ngt.

tr ngt

tr s kin ngt (thi gian tnh t thng bo ca CPU rng mt s kin

xut hin cho n khi CPU bt u vic thc thi ca lnh u tin trong OB phc v s

kin) l xp x 210 micro giy, cho bit rng mt OB chu k chng trnh ch l

chng trnh con phc v s kin kch hot ti thi im ca s kin ngt.




Nhn bit cc s kin li thi gian

S xut hin ca bt k trong mt s cc iu kin li thi gian khc nhau, gy

ra kt qu l mt s kin li thi gian. Cc s kin li thi gian sau y l c h tr:

Thi gian chu trnh ti a b vt qu

OB c yu cu khng th c khi ng

S trn ra trong hng ch xut hin

iu kin thi gian chu trnh ti a b vt qu xy ra khi chu k chng trnh

khng hon tt trong khong thi gian chu trnh qut ti a c nh trc.

iu kin OB c yu cu khng th c khi ng xy ra khi mt OB c

yu cu bi mt ngt theo chu trnh hay mt ngt tr hon thi gian, nhng OB c

yu cu li va mi ang c thc thi.

iu kin trn ra trong hng ch xy ra khi cc ngt xut hin nhanh hn so vi

tc chng c x l. S lng cc s kin ch (xp hng) c gii hn bng

cch s dng mt hng ch khc nhau cho mi kiu s kin. Nu mt s kin xut

hin khi hng ch tng ng ang y, mt s kin li thi gian c sinh ra.

Tt c cc s kin li thi gian s kch hot s thc thi ca OB 80 nu c. Nu

OB 80 khng tn ti, CPU s b qua li ny. Nu hai iu kin thi gian chu trnh ti

a b vt qu xut hin trong cng mt chu k chng trnh m khng t li b nh

th chu k, CPU s chuyn v ch STOP, bt chp OB 80 c tn ti hay khng.

OB 80 bao gm cc thng tin khi ng gip ta xc nh s kin v OB no

sinh ra li. Ta c th lp trnh tp lnh bn trong OB 80 kim tra cc gi tr khi

ng ny v thc hin thao tc thch hp. Cc vng khi ng sau y c h tr

bi OB 80:





fault_id BYTE

16#01 thi gian chu trnh ti a b vt qu

16#01 OB c yu cu khng th c khi ng

16#07 vaf 16#09 s trn qu hng ch xut hin

csg_OBnr ON_ANY S hiu ca OB ang c thc thi khi li xut hin

csg_prio UINT Mc u tin ca OB gy ra li

Khng c OB 80 ngt li thi gian no hin din khi ta to ra mt n mi.

Nu mun, ta thm mt OB 80 ngt li thi gian vo n bng cch nhp i chut

vo Add new block pha di Program blocks, sau chn Organization block

v Time error interrupt.

Nhn bit cc s kin li chn on

Mt vi thit b c kh nng pht hin v bo co li cc li chn on. S xut

hin hay vic g b ca bt k trong mt s cc iu kin li chn on khc nhau s

gy ra mt s kin li chn on. Cc li chn on sau y l c h tr:

Khng c ngun in ca ngi dng

Gii hn cao b vt qu

Gii hn thp b vt qu

t dy ni

Ngn mch

Tt c cc s kin li chn on s kch hot s thc thi ca OB 82 nu n tn

ti. Nu OB 82 khng tn ti, CPU sau s b qua li. Khng c OB 82 ngt li

chn on no hin din khi ta to ra mt n. Nu mun, ta thm mt OB 82 ngt

li chn on vo n bng cch nhp i chut vo Add new block pha di

Program blocks, sau chn Organization block v Diagnostic error interrupt.

OB 82 bao gm cc thng tin khi ng gip ta xc nh khi no s kin l da

vo s xut hin hay s g b mt li, v thit b cng vi knh m bo co li li .




Ta c th lp trnh tp lnh bn trong OB 82 kim tra cc gi tr khi ng ny v

thc hin thao tc thch hp. Cc vng khi ng sau y c h tr bi OB 82:


IOstate WORD Trng thi I/O ca thit b

laddr HW_ANY Nhn dng phn cng ca thit b hay ca hm cho n

khi n bo co li li

channel UINT S hiu knh

multierror BOOL Nhn gi tr TRUE nu c nhiu hn mt li hin din

Bit 4 ca IO_state biu th khi no s kin l do bi s xut hin hay s g b

ca mt li. Bit 4 s bng 1 nu mt li hin din (v d: t dy ni) v bng 0 nu li

khng hin din.

Ng vo ladder cha b nh danh phn cng (HW ID) ca thit b hay cc n

v chc nng tr v li. HW ID c gn mt cch t ng khi cc thnh phn c

lp vo thit b hay kiu xem mng v xut hin trong th Constants ca cc th ghi

PLC. Mt tn gi cn c gn mt cch t ng cho HW ID. Cc mc nhp ny

trong th Constants ca cc th ghi PLC l khng th thay i.

S hiu knh bt u ti gi tr 0 i vi im ng vo u tin (kiu tng t

hay kiu s) v bt u ti gia tr 64 i vi im ng ra u tin (kiu tng t hay

kiu s). Nhng s dch chnh khc nhau l cn thit phn bit cc ng vo vi cc

ng ra trong s kin m thit b cha c hai. Nu mt li nh hng n thit b hon

chnh v n v chc nng, v d nh khng c ngun, th bit c trng s ln nht ca

k t s hiu knh s c t (s hiu knh 32768).




Gim st thi gian chu trnh

Thi gian chu trnh l thi gian m h iu hnh CPU cn thit thc thi pha

theo chu k ca ch RUN. CPU cung cp c hai phng php gim st thi gian

chu trnh:

Thi gian chu trnh qut ti a

Thi gian chu trnh qut ti thiu c nh

Vic gim st chu trnh qut bt u sau khi s kin khi ng hon tt. S cu

hnh cho chc nng ny xut hin di mc Device Configuration ca CPU trong

Cycle time.

CPU lun lun gim st chu k qut v phn ng li nu thi gian chu trnh

qut ti a b vt qu. Nu thi gian chu trnh qut ti a b vt qu, mt li c

sinh ra v c x l theo mt trong hai cch sau:

Nu khng c OB 80 ngt li thi gian hin din, CPU s sinh ra mt li v tip

tc thc thi chng trnh ngi dng.

Nu mt OB 80 ngt li thi gian hin din, CPU s thc hin OB 80.

Lnh RE_TRIGR (kch hot li vic gim st thi gian chu trnh) cho php ta

t li b nh th o thi gian chu trnh. Tuy nhin lnh ny ch c tc dng nu n

c thc thi trong mt OB chu k chng trnh; lnh RE_TRIGR s b b qua nu

c thc thi trong OB 80. Nu thi gian chu trnh qut ti a b vt qu hai ln

trong cng mt chu k chng trnh m khng c s thc thi lnh RE_TRIGR gia c

hai ln, CPU sau s chuyn v STOP ngay lp tc. Vic s dng cc s thc thi lp

li ca lnh RE_TRIGR c th to ra mt vng lp v tn hay mt chu trnh qut rt

di.

Thng thng, chu trnh qut thc thi nhanh nht c th v chu trnh qut k

tip bt u ngay khi chu trnh qut hin thi hon tt. Ph thuc theo chng trnh

ngi dng v cc tc v truyn thng, thi gian chu trnh ca mi chu trnh qut c

th khc nhau gia cc chu trnh qut. loi b s khc nhau ny, CPU h tr mt

thi gian chu trnh qut ti thiu c nh (cn c gi l chu trnh qut c nh) ty




chn. Khi chc nng ty chn ny c kch hot v mt thi gian chu trnh qut ti

thiu c nh c cung cp theo mili giy, CPU s duy tr thi gian chu trnh ti thiu

trong khong 1 ms i vi s hon thnh ca mi chu trnh qut CPU.

Trong mt s kin m CPU hon tt chu trnh qut bnh thng trong khong

thi gian nh hn thi gian chu trnh qut ti thiu c nh trc, CPU s s dng

thi gian b sung ca chu trnh qut thc hin cc chn on thi gian vn hnh

v/hoc x l cc yu cu truyn thng. Theo cch ny CPU lun lun mt mt

lng thi gian c nh hon tt mt chu trnh qut.

Trong mt s kin m CPU khng th hon tt chu trnh qut trong khong thi

gian chu trnh ti thiu c xc nh, CPU s hon tt chu trnh qut mt cch bnh

thng (bao gm c vic x l truyn thng) v khng to ra bt k phn ng h thng

no nh l kt qu ca vic vt qu thi gian qut ti thiu. Bng sau y xc nh

phm vi v cc mc nh i vi cc chc nng gim st thi gian chu trnh:

Thi gian chu trnh Phm vi (ms) Mc nh

Thi gian chu trnh qut ti a 1 1 n 6000 150 ms

Thi gian chu trnh qut ti thiu c nh

2

1 n thi gian chu trnh qut ti

a B v hiu

1 Thi gian chu trnh qut ti a lun lun c kch hot. Ta cu hnh mt thi gian

chu trnh gia 1 ms n 6000 ms. Mc nh l 150 ms.

2 Thi gian chu trnh qut ti thiu l ty chn, v theo mc nh n b v hiu ha.

Nu cn thit ta cu hnh mt thi gian chu trnh gia 1 ms v thi gian chu trnh qut

ti a.




Cu hnh thi gian chu trnh v np truyn thng

Ta s dng cc thuc tnh ca CPU trong Device Configuration cu hnh cc

thng s sau y:

Thi gian chu trnh: ta nhp vo mt thi gian chu trnh qut ti a. Cng c th

nhp vo mt thi gian chu trnh qut ti thiu c nh.

Np truyn thng: ta c th cu hnh mt gi tr phn trm ca thi gian chuyn

dng cho cc tc v truyn thng.




2.1.3. B nh CPU.

S qun l b nh

CPU cung cp cc vng nh sau y lu tr chng trnh ngi dng, d

liu v cu hnh:

B nh np l mt vng lu tr khng bin i dnh cho chng trnh ngi

dng, d liu v cu hnh. Khi mt n c ti xung vo CPU, trc tin n

c lu tr trong vng b nh np. Vng ny c t trong c trong mt th

nh (nu c) hay trong CPU. Vng nh khng bin i ny vn c duy tr

khi mt ngun in. Th nh h tr mt khng gian lu tr ln hn vng lu

tr c tch hp trong CPU.

B nh lm vic l mt vng lu tr dnh cho mt vi phn t ca n ngi

dng trong khi ang thc thi chng trnh ngi dng. CPU sao chp mt s

phn t trong n t b nh np vo trong b nh lm vic. B nh bin i

ny b mt i khi mt ngun, v n c lu tr bi CPU khi ngun c khi

phc li.

B nh gi li l mt vng lu tr khng bin i dnh cho mt s lng gii

hn cc gi tr b nh lm vic. Vng b nh gi li c s dng lu tr

cc gi tr ca cc v tr nh dnh cho ngi dng c chn trong sut thi

gian khng c ngun. Khi ngun c bt tr li, CPU c thi gian gi li

duy tr cc gi tr ca mt s lng gii hn cc v tr nh c bit. Cc gi

tr gi li ny sau c khi phc li khi ngun c bt.

hin th vi s dng b nh i vi n hin thi, nhp chut phi vo

CPU (hay mt trong cc khi ca CPU) v la chn Resources t ng cnh. hin

th vic s dng ca CPU hin thi, nhp i chut ln Online and diagnostics, m

rng phn Diagnostics v la chn Memory.

B nh lu gi

Vic mt i d liu sau khi ngun gp s c c th c trnh bng cch thao tc cc

d liu chc chn theo dng lu gi. Cc d liu sau y c th c cu hnh c

lu gi:




B nh bit (M): ta c th xc nh rng chnh xc ca b nh i vi mi b

nh bit trong bng th ghi PLC hay trong danh sch gn. B nh bit lu gi

lun lun khi u ti MB0 v chy ln lin tip n mt s lng xc nh cc

byte. Ta xc nh gi tr ny t bng th ghi PLC hay trong danh sch gn bng

cch nhp chut ln biu tng Retain. Nhp vo s lng cc byte M gi

li khi u ti MB0.

Cc th ghi trong mt khi hm (FB): nu mt khi hm c to ra vi hp

Symbolic access only c chn, giao din trnh son tho cho FB ny sau

s cha mt ct Retain. Trong ct ny, ta c th la chn c Retain hay

Non-retain mt cch ring bit cho mi th ghi. Mt DB tc thi c to

ra khi FB ny c t trong trnh son tho s cho thy ct gi li ny, nhng

ch cho mc ch hin th; ta khng th thay i trng thi lu gi t trong trnh

son tho giao din DB tc thi cho mt FB m FB c cu hnh l

Symbolic access only.

Nu mt FB c to ra vi hp Symbolic access only c hy la chn,

trnh son tho giao din cho FB ny s khng bao gm ct Retain. Mt DB tc thi

c to ra khi FB ny c chn vo trong trnh son tho chng trnh s cho

thy mt ct Retain c th chnh sa. Trong trng hp ny, vic la chn ty chn

Retain cho bt k mi th ghi s a n kt qu l tt c cc th ghi c la chn.

Tng t, vic hy la chn ty chn i vi bt k mi th ghi s a n kt qu l

tt c cc th ghi c hy la chn. i vi mt FB c cu hnh khng phi l

Symbolic access only, ta c th thay i trng thi lu gi t trong phm vi trnh

son tho DB tc thi, nhng tt c cc th ghi s c thit lp n trng thi lu gi

cng vi nhau.

Sau khi to ra FB, ta khng th thay i ty chn i vi Symbolic access

only. Ty chn ny ch c th c la chn khi FB c to ra. xc nh khi no

mt FB c sn c cu hnh cho Symbolic access only, nhp chut phi ln FB

trong cy Project, la chn Properties, v sau la chn Attributes.

Cc th ghi ca mt khi d liu tng th: trng thi ca mt DB tng th lin

quan n vic gn trng thi lu gi th ging vi trng thi ca mt FB. Ph




thuc vo vic thit lp i vi vic ghi a ch biu tng, ta c th xc nh

trng thi lu gi c i vi mt th ghi ring l hay i vi ton b th ghi ca

mt khi d liu tng th.

- Nu thuc tnh Symbolic access only ca DB c nh du chn, trng thi

lu gi c th c thit lp cho mi th ghi ring l.

- Nu thuc tnh Symbolic access only ca DB khng c nh du chn,

trng thi lu gi c p dng n tt c cc th ghi ca DB, tc l hoc tt c

th ghi l lu gi hoc khng c th ghi no l lu gi.

Tng cng 2048 byte d liu c th l lu gi. xem c bao nhiu byte, t

bng th ghi PLC hay t danh sch gn, ta nhp chut ln biu tng thanh cng c

Retain. Dng th hai s ch ra tng b nh cn li c kt hp cho M v DB, mc

d y l ni m cc phm vi lu gi c xc nh cho b nh M.

B m chn on

CPU h tr mt b m chn on cha mt mc nhp vo cho mi s kin

chn on. Mi mc nhp vo bao gm ngy v gi m s kin xut hin, mt danh

mc s kin v mt phn miu t s kin. Cc mc nhp vo c hin th theo th t

thi gian vi s kin gn nht trn cng. Trong khi CPU duy tr ngun in, c ti

a 50 s kin gn nht nm trong nht k ny. Khi nht k y, mt s kin mi s

thay th s kin xy ra lu nht trong nht k. Khi ngun b mt, 10 s kin gn y

nht s c lu li.

Cc kiu s kin sau y c ghi li trong b m chn on:

Mi s kin chn on h thng, v d cc li CPU v cc li module

Mi s thay i trng thi ca CPU (mi khi bt ngun, mi s chuyn i sang

STOP, mi s chuyn i sang RUN)

truy xut b m chn on, ta phi ang trc tuyn. Ta t nht k di mc

Online & Diagnostics/ Diagnostics/ Diagnostics buffer.




ng h gi trong ngy

CPU h tr mt ng h gi trong ngy. Mt t in c ln cung cp nng

lng cn thit gi ng h chy trong sut thi gian m CPU c tt ngun. T

in ny c np trong lc CPU c cp ngun. n t nht l 2 gi sau khi CPU

c tt ngun, t in c ln ny s c np y gi cho ng h vn hnh trong

khong thng l 10 ngy.

ng h gi trong ngy (Time of Day Clock) c t theo gi h thng l gi

quc t phi hp (Coordinate Universal Time UTC). C cc lnh c gi h

thng (RD_SYS_T) hay gi cc b (RD_LOC_T). Gi cc b c tnh ton bng

cch s dng mi gi v dch chnh tit kim nh sng ngy m ta thit lp trong

mc Device configuration phn CPU Clock.

Ta cu hnh ng h gi trong ngy dnh cho CPU di thuc tnh Time of

day. Ta cn c th kch hot thi gian tit kim nh sng ngy v xc nh cc thi

im khi ng v dng i vi thi gian tit kim nh sng ngy. thit lp ng

h gi trong ngy, ta phi ang trc tuyn v trong kiu xem Online &

Diagnostics ca CPU. S dng chc nng Set time of day.

B nh h thng v b nh m thi gian

Ta s dng cc thuc tnh CPU kch hot cc byte dnh cho system

memory v clock memory. Logic chng trnh c th tham chiu cc bit ring l

ca cc hm ny.

Ta c th gn mt byte trong b nh M cho b nh h thng. Byte ca b nh

h thng cung cp 4 bit sau y c th c tham chiu bi chng trnh ngi

dng:

- Bit Always 0 (low) lun lun c t v 0.

- Bit Always 1 (high) lun lun c t ln 1.

- Diagnostic graph changed c t ln 1 i vi mt chu k qut sau khi

CPU ghi mt s kin chn on. V CPU khng t bit diagnostic graph

changed cho n kt thc ca ln thc thi u tin ca cc OB chu k chng

trnh, chng trnh ngi dng khng th pht hin c mt thay i chn on




c trong sut s thc thi ca cc OB khi ng hay trong ln thc thi u tin

ca cc OB chu k chng trnh.

- Bit First scan c t ln 1 i vi khong thi gian ca ln qut u tin

sau khi OB khi ng hon tt. (Sau s thc thi ca ln qut u tin, bit First

scan c t v 0)

Ta c th gn mt byte trong b nh M cho b nh m thi gian. Mi bit ca

byte c cu hnh ng vai tr nh b nh m thi gian s sinh ra mt xung

dng sng vung. Byte ca b nh m thi gian cung cp 8 tn s khc nhau,

t 0,5 Hz (chm) n 10 Hz (nhanh). Ta c th s dng cc bit ny nh cc bit

iu khin, c bit khi kt hp vi cc lnh sn, kch hot cc hot ng

trong chng trnh ngi dng trn mt nn tng theo chu trnh.

CPU khi chy cc byte ny trn s chuyn i t ch STOP sang ch

STARTUP. Cc bit ca b nh m thi gian thay i mt cch ng b n ng h

CPU xuyn sut cc ch STARTUP v RUN.

CH

Vic ghi ln cc bit ca b nh h thng hay b nh m thi gian c th lm sai lc d

liu trong cc chc nng ny v lm cho chng trnh ngi dng vn hnh khng chnh

xc, iu ny c th gy ph hy thit b v gy thng tch cho con ngi.

Bi v c b nh m thi gian v b nh h thng u khng c d tr trong b nh M,

cc lnh hay truyn thng c th ghi n cc v tr ny v lm sai lc d liu.

Trnh vic ghi d liu n cc v tr ny m bo s vn hnh ring ca cc chc nng

ny, v lun lun lp t mt mch dng khn cp dnh cho quy trnh hay b my.




B nh h thng cu hnh mt

byte m byte s bt (gi tr = 1) trong

cc iu kin sau y:

First scan: byte c bt i vi

ln qut u tin trong ch

RUN

Diagnostic graph changed:

- Always 1 (high): lun lun bt

- Always 0 (low): lun lun tt

B nh m thi gian s cu

hnh mt byte m byte bt v tt mt

cc tun hon cc bit ring l ti cc

khong thi gian dng c nh.

Cc c ca b m thi gian

sinh ra mt xung sng vung tng ng

vi bit b nh M. Cc bit ny c th

c s dng nh cc bit iu khin,

c bit khi kt hp vi cc lnh sn,

kch hot cc hot ng trong

chng trnh ngi dng da trn mt

nn tng theo chu trnh.




Cu hnh trng thi ca cc gi tr ng ra khi CPU trong ch STOP

Ta c th cu hnh trng thi ca cc ng ra kiu s v kiu tng t khi CPU

ang trong ch STOP. i vi bt k ng ra no ca mt CPU, SB hay SM, ta c

th thit lp cc ng ra hoc gn cht gi tr hoc s dng mt gi tr thay th:

Thay th mt gi tr ng ra c nh trc (mc nh): ta nhp vo mt gi tr

thay th cho mi ng ra (mi knh) ca thit b CPU, SB hay SM .

Gi tr thay th mc nh cho cc knh ng ra kiu s l OFF, v gi tr thay th

mc nh cho cc knh ng ra kiu tng t l 0.

Gn cht cc ng ta duy tr trng thi cui cng: cc ng ra gi li gi tr

hin thi ca chng ti thi im ca s chuyn tip t RUN sang STOP. Sau

khi bt ngun, cc ng ra c t n gi tr thay th mc nh.

Ta cu hnh trng thi ca cc ng ra trong Device Configuration. La chn cc

thit b ring l v s dng th Properties cu hnh cc ng ra cho mi thit b.

Khi CPU chuyn t RUN sang STOP, CPU gi li nh tin trnh v ghi cc gi

tr tng ng cho c cc ng ra kiu s v kiu tng t, da vo s cu hnh.




2.1.4. Bo v bng mt khu cho CPU S7-1200.

CPU cung cp 3 cp bo mt hn ch s truy cp n mt s chc nng

ring bit. Khi cu hnh cp bo mt v mt khu cho mt CPU, ta gii hn cc

chc nng v cc vng nh m c th truy cp khng cn nhp vo mt khu.

cu hnh mt khu ta lm theo cc

bc sau y:

1. Trong mc Device configuration,

la chn CPU.

2. Trong ca s kim tra, la chn th

Properties.

3. La chn thuc tnh Protection

chn cp bo v v nhp vo mt

khu.

Mt khu l nhy vi loi ch.

Mi cp cho php cc chc nng bit c th truy cp m khng cn

mt mt khu. iu kin mc nh cho CPU l phi khng c s hn ch no v khng

c mt s bo v bng mt khu no. hn ch vic truy xut n mt CPU, ta cu

hnh cc thuc tnh ca CPU v nhp vo mt khu.

Vic nhp vo mt khu thng qua mt mng s khng lm gim gi tr ca s

bo v bng mt khu cho CPU. Mt CPU c bo v bng mt khu ch cho php

mt ngi dng khng b hn ch truy xut ti mt thi im. S bo v bng mt

khu khng p dng n s thc thi ca tp lnh chng trnh ngi dng bao gm

cc hm truyn thng. Vic nhp vo mt khu chnh xc s cung cp truy xut n tt

c cc chc nng.

Truyn thng PLC n PLC (s dng tp lnh truyn thng trong cc khi m)

l khng b hn ch bi cp bo mt trong CPU. Chc nng HMI cng khng b

hn ch.




Cp bo mt Nhng s hn ch truy cp

No protection Cho php truy xut ton din m khng cn bo v bng mt khu.

Write protection

Cho php truy xut HMI v tt c cc hnh thc truyn thng PLC n

PLC m khng cn bo v bng mt khu.

Mt khu c yu cu dnh cho vic chnh sa (ghi n) CPU v cho

vic thay i ch CPU (RUN/STOP).

Read/write

protection

Cho php truy xut HMI v tt c cc hnh thc truyn thng PLC n

PLC m khng cn bo v bng mt khu.

Mt khu c yu cu dnh cho vic c d liu trong CPU, cho vic

chnh sa (ghi n) v cho vic thay i ch CPU (RUN/STOP).

2.1.5. S phc hi t mt mt khu b mt.

Nu nh mt mt khu ca mt CPU c bo v bng mt khu, ta s

dng mt th chuyn trng xa i chng trnh c bo v bng mt khu. Th

chuyn trng s xa b nh np bn trong ca CPU. Sau ta c th ti xung mt

chng trnh ngi dng mi t phn mm STEP 7 Basic n CPU.

CH

Nu ta lp mt th chuyn vo trong mt CPU ang chy, CPU s chuyn sang ch

STOP. Cc thit b iu khin c th ri vo mt iu kin khng an ton, kt qu l s vn

hnh khng mong mun ca thit b c iu khin. Mt s cc vn hnh khng mong

mun c th gy hu qu t vong hay tn thng nghim trng n con ngi, v/hoc ph

hy thit b.

Ta phi ly th chuyn ra trc khi thit lp CPU sang ch RUN.




2.2. Lu tr d liu, cc vng nh v vic ghi a ch.

CPU cung cp mt s cc ty chn dnh cho vic lu tr d liu trong sut s

thc thi chng trnh ngi dng:

Global memory (b nh ton cc): CPU cung cp nhiu vng nh chuyn mn

ha, bao gm cc ng vo (I), cc ng ra (Q) v b nh bit (M). B nh ny l

c th truy xut bi tt c cc khi m m khng c s hn ch no.

Data block (DB khi d liu): ta c th bao gm cc DB trong chng trnh

ngi dng lu tr d liu cho cc khi m. D liu c lu tr vn duy tr

khi s thc thi ca mt khi m c lin quan dn kt thc.

Temp memory (b nh tm thi): khi mt khi m c gi, h iu hnh ca

CPU phn b b nh tm thi hay cc b (L) s dng trong sut s thc thi

ca khi. Khi s thc thi ca khi hon thnh, CPU s phn b li b nh cc

b dnh cho vic thc thi cc khi m khc.

Mi v tr b nh khc nhau c mt a ch n nht. Chng trnh ngi dng

s dng cc a ch ny truy xut thng tin trong v tr b nh.

Vng nh Miu t p buc Lu gi

I

Ng vo nh tin trnh

I_:P

Ng vo vt l

c sao chp t cc ng vo vt l ti

im bt u ca chu trnh qut Khng Khng

Vic c ngay lp tc ca cc im ng

vo trn CPU, SB v SM C Khng

Q

Ng ra nh tin trnh

Q_:P

Ng ra vt l

c sao chp n cc ng ra vt l ti

im bt u ca chu trnh qut Khng Khng

Vic ghi ngay lp tc n cc im ng

ra vt l trn CPU, SB v SM C Khng

M

B nh bit B nh d liu v iu khin Khng C

L

B nh tm thi

D liu tm thi cho mt khi, mt b

phn ca khi Khng Khng

DB

Khi d liu

B nh d liu v cn l b nh thng s

dnh cho cc FB Khng C




Mi vng nh khc nhau c mt a ch n nht. Chng trnh ngi dng s

dng cc a ch ny truy xut thng tin trong v tr b nh. Hnh di y th hin

cch thc truy xut mt bit (cn c gi l ghi a ch byte.bit). Trong v d ny,

vng b nh v a ch byte (I = ng vo v 3 = byte 3) c theo sau bi mt du

chm (.) ngn cch a ch bit (bit 4).

A B nh danh vng nh

B a ch byte: byte 3

C Du ngn cch

D V tr bit ca byte (bit 4 trong s 8

bit)

E Cc byte ca vng nh

F Cc bit ca byte c chn

Ta c th truy xut d liu trong hu ht cc vng b nh (I, Q, M, DB v L)

gm cc kiu Byte, Word, hay Double Word bng cch s dng nh dng byte

address. truy xut mt d liu Byte, Word, hay Double Word trong b nh, ta

phi xc nh a ch theo cch ging nh xc nh a ch cho mt bit. iu ny bao

gm mt b nh danh vng, k hiu kch thc d liu, v a ch byte bt u ca

gi tr Byte, Word, hay Double Word. Cc k hiu kch thc l B (Byte), W (Word)

v D (Double Word), v d IB0, MW20 hay QD8. Cc tham chiu nh l I0.3 v Q1.7

s truy xut nh tin trnh. truy xut ng vo hay ng ra vt l, ta cng thm tham

chiu vi k t :P (nh l I0.3:P, Q1.7:P hay Stop:P).




Truy xut d liu trong cc vng nh ca CPU

Phn mm STEP 7 Basic to iu kin cho vic lp trnh k hiu. Thng

thng, cc th ghi c to ra c trong th ghi PLC, trong mt khi d liu hay trong

giao din ti pha trn ca mt OB, FC hay FB. Cc th ghi ny bao gm tn, kiu d

liu, dch chnh v ch gii. Ngoi ra, trong mt khi d liu, mt gi tr ban u c

th c xc lp. Ta c th s dng cc th ghi ny khi lp trnh bng cch nhp vo

tn th ghi ti thng s ca lnh. Mt cch ty chn, ta cng c th nhp vo ton hng

c lp (b nh, vng nh, kch c v dch chnh) ti thng s lnh. Cc v d trong

phn sau y cho thy cch thc nhp vo cc ton hng tuyt i. K t % c t

ng chn vo trc ton hng tuyt i bi trnh son tho chng trnh. Ta c th lt

chuyn kiu xem trong trnh son tho chng trnh n mt trong cc kiu sau: biu

tng (Symbolic), biu tng v tuyt i (Symbolic and absolute) hay tuyt i

(Absolute).

I (ng vo nh tin trnh): CPU tin hnh ly mu cc im ng vo vt l

ngoi vi va trc khi thc thi OB chu trnh ca mi chu trnh qut v ghi cc gi tr

ny n nh tin trnh ng vo. Ta c th truy xut n nh tin trnh ng vo theo bit,

byte, word hay double word. C truy xut c v ghi u c cho php, nhng thng

thng, cc ng vo nh tin trnh l ch c.

Bit I [a ch byte].[a ch bit] I0.1

Byte, Word hay Double Word I [kch thc].[a ch byte khi u] IB4, IW5 hay ID12

Bng cch cng thm :P n mt a ch, ta c th c ngay lp tc cc ng

vo kiu s hay kiu tng t ca CPU, SB hay SM. S khc bit gia mt truy xut

s dng I_:P thay v s dng I l ch d liu s n mt cch trc tip t cc im

ang c truy xut hn l t nh tin trnh ng vo. Truy xut I_:P c tham chiu

n mt truy xut immediate read v d liu c truy tm ngay tc khc t ngun

thay v t mt bn sao chp c to ra trong ln cui m nh tin trnh ng vo

c cp nht.




V cc im ng vo vt l nhn cc d liu ca chng mt cch trc tip t cc

thit b trng c kt ni n cc im ny, vic ghi n cc im ny l b cm.

iu c ngha l, cc truy xut I_:P l ch c, tri vi cc truy xut I c th c

c hay ghi.

Cc truy xut I_:P cn c th b hn ch theo kch thc ca cc ng vo c

h tr bi mt CPU, SB hay SM n l, c lm trn ln n byte gn nht. V d,

nu cc ng vo ca mt SB c 2 DI/ 2DQ c cu hnh khi ng ti I4.0, khi

cc im ng vo c th c truy xut theo a ch I4.0:P v I4.1:P hay theo IB4:P.

Cc truy xut n a ch tnh t I4.2:P cho ti I4.7:P l khng b t chi, nhng khng

c nhn bit, v cc im ny khng c s dng. Cc truy xut n a ch IW4:P

v ID4:P b cm bi chng vt qu dch chnh byte c lin quan vi SB.

Cc truy xut s dng I_:P khng nh hng n gi tr tng ng c lu tr

trong nh tin trnh ng vo.

Bit I [a ch byte].[a ch bit]:P I0.1:P

Byte, Word hay Double Word I [kch thc].[a ch byte khi u]:P IB4:P, IW5:P hay ID12:P

Q (ng ra nh tin trnh): CPU sao chp cc gi tr c lu tr trong nh tin

trnh ng ra n cc im ng ra vt l. Ta c th truy xut nh tin trnh ng ra theo

bit, byte, word hay double word. C truy xut c v ghi u c cho php i vi

cc ng ra nh tin trnh.

Bit Q [a ch byte].[a ch bit] Q0.1

Byte, Word hay Double Word Q [kch thc].[a ch byte khi u] QB5, QW10 hay QB40

Bng cch cng thm :P n mt a ch, ta c th ghi ngay lp tc n cc

ng ra kiu s hay kiu tng t ca CPU, SB hay SM. S khc bit gia mt truy

xut s dng Q_:P thay v s dng Q l ch d liu s di chuyn mt cch trc tip

n cc im ang c truy xut bn cnh n nh tin trnh ng ra (ghi n c hai

ni). Truy xut Q_:P i khi c tham chiu n nh mt truy xut immediate




write v d liu c gi ngay tc khc n im ch; im ch khng phi ch ti

ln cp nht k tip t nh tin trnh ng ra.

V cc im ng ra vt l iu khin trc tip cc thit b trng c kt ni

n cc im ny, vic c t cc im ny l b cm. iu c ngha l, cc truy

xut Q_:P l ch ghi, tri vi cc truy xut Q c th c c hay ghi.

Cc truy xut Q_:P cn c th b hn ch theo kch thc ca cc ng ra c

h tr bi mt CPU, SB hay SM n l, c lm trn ln n byte gn nht. V d,

nu cc ng ra ca mt SB c 2 DI/ 2DQ c cu hnh khi ng ti Q4.0, khi

cc im ng ra c th c truy xut theo a ch Q4.0:P v Q4.1:P hay theo QB4:P.

Cc truy xut n a ch tnh t Q4.2:P cho ti Q4.7:P l khng b t chi, nhng

khng c nhn bit, v cc im ny khng c s dng. Cc truy xut n a ch

QW4:P v QD4:P b cm bi chng vt qu dch chnh byte c lin quan vi SB.

Cc truy xut s dng Q_:P nh hng n c ng ra vt l cng nh gi tr

tng ng c lu tr trong nh tin trnh ng ra.

Bit Q [a ch byte].[a ch bit]:P Q0.1:P

Byte, Word hay Double Word Q [kch thc].[a ch byte khi

u]:P

QB4:P, QW5:P hay

QD12:P

M (vng nh bit): ta s dng vng nh bit (b nh M) dnh cho c cc relay

iu khin v d liu dng lu tr trng thi tc thi ca mt s vn hnh hay ca

cc thng tin iu khin khc. Ta c th truy xut vng b nh bit theo bit, byte, word

hay double word. C vtruy xut c v ghi u c cho php i vi b nh M.

Bit M [a ch byte].[a ch bit] M26.7

Byte, Word hay Double Word M [kch thc].[a ch byte khi u] MB20, MW30, MD50




Temp (b nh tm): CPU phn b b nh tm thi trn mt nn tng theo yu

cu. CPU phn b b nh tm thi cho khi m ti thi im khi khi m c bt u

(i vi mt OB) hay c gi (i vi mt FC hay mt FB). S phn b b nh tm

thi cho mt khi m c th s dng li cng mt v tr b nh Temp c s dng

trc bi mt OB, FC hay FB khc. CPU khng thit lp gi tr ban u cho b nh

tm thi ti thi im phn b v do b nh tm thi c th cha bt k gi tr no.

B nh tm thi ging vi b nh M ngoi tr mt im chnh: b nh M c

mt di hp l l global (tng th) cn b nh tm thi c di hp l l local (cc

b).

B nh M: bt k cc OB, FC hay FB no cng c th truy xut d liu trong

b nh M, ngha l cc d liu trong b nh M l sn sng mt cch ton din

cho tt c cc phn t ca chng trnh ngi dng.

B nh Temp: truy xut n d liu trong b nh tm b hn ch n OB, FC

hay FB m to ra hay khai bo vng b nh tm. Cc v tr b nh tm gi

nguyn cc b v khng c chia s bi cc khi m khc, ngay c khi khi

m gi mt khi m khc. V d: khi mt OB gi mt FC, FC khng th truy

xut b nh tm ca OB gi n.

CPU cung cp b nh tm (cc b) cho mi nhm trong s 3 nhm u tin:

16 kB dnh cho khi ng c chu k chng trnh, bao gm c cc FB v FC c

lin quan.

4 kB cho cc s kin ngt tiu chun bao gm c cc FB v cc FC.

4 kB cho cc s kin ngt chn on bao gm c cc FB v cc FC.

Ta ch truy xut b nh tm bng cch ghi a ch k hiu.

DB (khi d liu): ta s dng b nh DB dnh cho vic lu tr cc kiu d

liu khc nhau, bao gm trng thi trung gian ca mt hot ng hay cc thng s v

thng tin iu khin khc cho cc FB, v cc cu trc d liu cn thit cho nhiu lnh

nh cc b nh th hay cc b m. Ta c th xc nh mt khi d liu c

c/ghi hay l ch c. Ta c th truy xut b nh khi d liu theo bit, byte, word hay




double word. C truy xut c v truy xut ghi u c cho php i vi cc khi d

liu c/ghi. Ch truy xut c l c cho php i vi cc khi d liu ch c.

Bit DB [s hiu khi d liu].DBX [a

ch byte].[a ch bit] DB1.DBX2.3

Byte, Word hay Double Word DB [s hiu khi d liu].DB [kch

c].[a ch byte bt u]

DB1.DBB4, DB10.DBW2,

DB20.DBD8

Ghi a ch I/O trong CPU v cc module I/O

Khi ta thm mt CPU v cc

module I/O vo mn hnh cu hnh, cc

a ch I v Q c gn mt cch t

ng.

Ta c th thay i vic ghi a

ch mc nh bng cch la chn

trng a ch trong mn hnh cu hnh

v g vo cc s hiu mi. Cc ng vo

v ng ra kiu s c gn theo mt

byte gm 8 bit, d cho module c s

dng tt c cc im hay khng.

Cc ng vo v ng ra kiu

tng t c gn theo nhm gm 2

im (4 byte). Trong v d ny, ta c

th thay i a ch ca DI16 v 2 .. 3

thay v 8 .. 9. Cng c s h tr bng

cch thay i cc phm vi a ch no

sai kch thc hay xung t vi cc a

ch khc.

Hnh trn th hin mt v d vi mt CPU cng 2 SM.




2.3. Cc kiu d liu.

Cc kiu d liu c s dng xc nh c kch thc ca mt phn t d

liu cng nh cch thc m d liu c din dch. Mi thng s lnh h tr t nht

mt kiu d liu, v mt s thng s cn h tr nhiu kiu d liu. Ta gi con tr qua

trng thng s ca mt lnh xem kiu d liu no c h tr i vi mt thng

s cho.

Mt thng s chnh thc l b nh danh trn mt lnh nh du v tr ca d

liu c s dng bi lnh (v d: ng vo IN1 ca mt lnh ADD). Thng s thc

t l v tr b nh hay hng s cha d liu dng cho lnh (v d %MD400

Number_of_Widgets). Kiu d liu ca thng s thc t c ch nh bi ngi

dng phi ph hp vi mt trong cc kiu d liu c h tr ca thng s chnh thc

c ch nh bi lnh.

Khi ch nh mt thng s thc t, ta phi ch nh c mt th ghi (k hiu) hay

mt a ch nh tuyt i. Cc th ghi c lin quan n mt tn k hiu (tn th ghi)

vi mt kiu d liu, mt vng nh, dch chnh b nh, v dng ch gii, v c th

c to ra c trong trnh son tho th ghi PLC hay trong trnh son tho Interface

cho mt khi (OB, FC, FB ay DB). Nu nhp vo mt a ch tuyt i m khng c

th ghi lin quan, ta phi s dng mt kch thc thch hp ph hp vi kiu d liu

c h tr, v mt th ghi mc nh s c to ra di mc nhp vo.

Ta cn c th nhp vo gi tr hng s cho nhiu thng s ng vo. Bng sau

y miu t cc kiu d liu c bn c h tr, gm cc v d ca mc nhp c nh.

Tt c cc kiu ngoi tr kiu String u c sn trong trnh son tho cc th ghi PLC

v trong trnh son tho Interface ca khi. Kiu String ch c sn trong trnh son

tho Interface ca khi. Bng sau y xc nh cc kiu d liu c bn.




Kiu d

liu

Kch

thc

(bit)

Phm vi Cc v d mc nhp vo

c nh

Bool 1 0 n 1 TRUE, FALSE, 0, 1

Byte 8 16#00 n 16#FF 16#12, 16#AB

Word 16 16#0000 n 16#FFFF 16#ABCD, 16#0001

DWord 32 16#00000000 n 16#FFFFFFFF 16#02468ACE

Char 8 16#00 n 16#FF A, t, @

SInt 16 -128 n 127 123, -123

Int 16 -32768 n 32767 123, -123

DInt 32 -2147483648 n 2147483647 123, -123

USInt 8 0 n 255 123

UInt 16 0 n 65535 123

UDInt 32 0 n 4294967295 123

Real 32 +/- 1.18 x 10 -38

n +/- 3.40 x 10 38 123456, -3.4, -1.2E+12,

3.4E-3

LReal 32 +/- 2.23 x 10 -308

n +/- 1.79 x 10 308 12345.123456789, -

1.2E+40

Time 32

T#-24d_20h_31m_23s_648ms n

T#24d_20h_31m_23s_647ms

c lu tr di dng : -2147483648

ms n +2147483647 ms

T#5m_30s

5#-2d

T#1d_2h_15m_30s_45ms

String Thay i Cc k t c kch thc 0 n 254

byte ABC




Mc d khng c sn nh mt kiu d liu, nh dng s BCD sau y c h tr bi

cc lnh chuyn i.

nh dng Kch thc (bit) Phm vi s Cc v d mc

nhp c nh

BCD16 16 -999 n 999 123, -123

BCD32 32 -9999999 n 9999999 1234567, -1234567

nh dng cho cc s thc

Cc s thc (hay s c du chm ng) c hin th i dng s vi chnh

xc n 32 bit (Real) hay s chnh xc kp 64 bit (LReal) nh c miu t trong

tiu chun ANSI/IEEE 754-1985. Cc s du chm ng vi chnh xc n l

chnh xc n ti a 6 ch s c ngha v cc s du chm ng vi chnh xc kp

l chnh xc n ti a 15 ch s c ngha. Ta c th ch nh ti a 6 ch s c ngha

(kiu Real) hay 15 ch s c ngha (LReal) khi nhp vo mt hng s du chm ng

duy tr chnh xc.

Cc tnh ton c lin quan n mt chui di cc gi tr gm cc s rt ln hay

rt nh c th to ra cc kt qu khng chnh xc. iu ny c th xut hin nu cc s

hn km nhau n 10 ly tha x, trong x > 6 (kiu Real) hay x > 15(kiu LReal).

V d i vi kiu Real: 100 000 000 + 1 = 100 000 000.

nh dng cho kiu d liu chui

CPU h tr kiu d liu String dnh lu tr mt tun t cc k t byte n

l. Kiu d liu String cha mt b m k t tng (s lng cc k t trong chui) v

b m k t hin thi. Kiu String cung cp ti a 256 byte cho vic lu tr kt qu

m k t tng ti a (chim 1 byte), kt qu m k t hin thi (chim 1 byte) v ti

a 254 k t, trong mi k t c lu tr trong 1 byte.

Ta c th s dng cc chui trc kin (hng s) cho cc thng s lnh ca kiu

IN bng cch s dng cc du nhy n. V d, mt chui gm 3 k t ABC c th

c s dng nh l ng vo cho thng s IN ca lnh S_CONV. Ta cn c th to ra




cc bin chui bng cch la chn kiu d liu String trong trnh son tho giao din

khi cho OB, FC, FB v DB. Ta khng th to ra mt chui trong trnh son tho th

ghi ca PLC. Ta c th xc nh kch thc chui ti a tnh theo byte khi khai bo

chui, v d, MyString[10] s xc nh kch thc ti a l 10 byte cho MyString.

Nu khng bao gm du ngoc vung vi b ch th kch thc ln nht, gi tr 254 s

c cho.

V d sau y xc nh mt chui vi gi tr m k t ti a bng 10 v gi tr

m k t hin thi bng 3. iu ny c ngha l hin thi chui cha 3 k t 1 byte,

nhng c th c m rng cha ti a 10 k t 1 byte.

B m k t

tng

B m k t

hin thi K t 1 K t 2 K t 3 K t 10

10 3 C

(16#43)

A

(16#41)

T

(16#54) -

Byte 0 Byte 1 Byte 2 Byte 3 Byte 4 Byte 11

Cc mng

Ta c th to ra mt mng cha nhiu phn t ca mt kiu c bn. Cc mng

c th c to ra trong trnh son tho gian din khi dnh cho OB, FC, FB v DB.

Ta khng th to ra mt mng trong trnh son tho th ghi PLC.

to ra mt mng t trnh son tho giao din khi, ta chn kiu d liu

Array [lohi] of type, sau chnh sa lo, hi v type nh sau:

lo ch s bt u (thp nht) ca mng

hi ch s kt thc (cao nht) ca mng

type mt trong cc kiu d liu c bn, nh l Bool, SInt, UDInt

Cc ch s m u c h tr. Ta c th t tn mng trong ct Name ca trnh

son tho giao din khi. Bng sau y cho thy cc v d ca cc mng nh chng c

th xut hin trong trnh son tho giao din khi.




Tn Kiu d liu Ch gii

My_Bits Array [1 .. 10] i vi kiu Bool Mng ny cha 10 gi tr Boolean

My_Data Array [-5 .. 5] i vi kiu SInt Mng ny cha 11 gi tr SInt, bao gm ch

mc 0

Ta tham chiu cc phn t ca mng trong chng trnh bng cch s dng c

php sau:

Array_name[i], trong i l ch mc mong mun.

Cc v d c th xut hin trong trnh son tho chng trnh nh mt ng vo

thng s:

#My_Bits[3] tham chiu bit th 3 ca mng My_Bits

#My_Data[-2] tham chiu bit th 4 ca mng My_Data

K hiu # c chn vo mt cch t ng bi trnh son tho chng trnh.

Kiu d liu DTL (Data and Time Long)

Kiu d liu DTL l mt cu trc gm 12 byte lu tr thng tin trn ngy v

gi trong mt cu trc c xc nh trc. Ta xc c th xc nh mt DTL c trong

b nh tm Temp ca khi hay trong mt DB.

di

(byte) nh dng Phm vi gi tr

V d v ng

vo gi tr

12

m thi gian v lch (Year-

Month:Hour:Minute:Second

.Nanosecond)

Ti thiu: DTL#1970-01-01-

:00:00:00.0

Ti a: DTL#2554-12-31-

:23:59:59.999999999

DTL#2008-12-

16-

20:30:20.250

Mi phn ca DTL cha mt kiu d liu khc nhau v phm vi ca cc gi tr.

Kiu d liu ca mt gi tr c nh trc phi ph hp vi kiu d liu ca cc

thnh phn tng ng.




Byte Thnh phn Kiu d liu Phm vi gi tr

0 Year

UInt

1970 n 2554

1

2 Month USInt 1 n 12

3 Day USInt 1 n 31

4 Day of week USInt 1 (Ch nht) n 2 (th by) Ngy trong tun

khng cn ch trong mc nhp gi tr

5 Hour USInt 0 n 23

6 Minute USInt 0 n 59

7 Second USInt 0 n 59

8 Nanosecond

UDInt

0 n 999 999 999

9

10

11




2.4. S dng th nh.

GHI CH

CPU ch h tr th nh SIMATIC c nh dng trc. Nu ta s dng mt phn mm

nh dng ca Windows nh dng li th nh SIMATIC, CPU khng th s dng th

nh c nh dng li ny.

Trc khi sao chp bt k chng trnh no n th nh c nh dng, ta phi xa tt

c chng trnh c lu trc khi th nh.

Ta s dng th nh ng vai tr va l th chuyn va l th chng trnh. Bt

k chng trnh no m ta sao chp n th nh u cha tt c cc khi hm v khi

d liu, cc i tng cng ngh v cu hnh thit b. Chng trnh khng cha cc

gi tr p buc.

Ta s dng mt th chuyn sao chp mt chng trnh n b nh np bn

trong ca CPU m khng cn s dng phn mm STEP 7 Basic. Sau khi lp th

chuyn vo, CPU trc tin s xa chng trnh ngi dng v xa mi gi tr

p buc khi b nh np bn trong, v sau sao chp chng trnh t th

chuyn n b nh np bn trong. Khi qu trnh chuyn i hon tt, ta phi ly

th chuyn ra.

Ta c th s dng mt th chuyn trng truy xut mt CPU c bo v

bng mt khu khi ta nh mt hay qun mt khu ny. Khi lp mt th chuyn cn

trng, chng trnh c bo v bng mt khu trong b nh np bn trong ca CPU

s b xa i. Sau ta c th ti xung mt chng trnh mi vo CPU.

Ta s dng mt th chng trnh ng vai tr l b nh np ngoi vi cho CPU.

Vic lp th chng trnh vo CPU s xa i ton b b nh np bn trong ca

CPU (bao gm chng trnh ngi dng v cc gi tr p buc). Sau CPU s

thc thi chng trnh ngi dng trong b nh np ngoi vi (tc l trong th

chng trnh). Vic ti xung n mt CPU m CPU c mt th chng

trnh s ch cp nht b nh np ngoi vi (th chng trnh).




V b nh np bn trong ca CPU c xa khi ta lp th chng trnh vo,

nn th chng trnh phi c gi nguyn trong CPU. Nu ly th chng trnh ra,

CPU s chuyn sang ch STOP. (n LED bo li nhp nhy ch th rng th

chng trnh b ly ra.)

Chng trnh trn mt th nh bao gm cc khi m, cc khi d liu, cc i

tng cng ngh v cu hnh thit b. Th nh khng cha bt k cc gi tr p buc

no. Cc gi tr p buc khng phi l mt phn ca chng trnh, nhng c lu tr

trong b nh np, hoc l trong b nh np bn trong ca CPU, hoc l trong b nh

np ngoi vi (mt th chng trnh). Nu mt th chng trnh c lp vo trong

CPU, phn mm STEP 7 Basic s ch p dng cc gi tr p buc n b nh np

ngoi vi trn th chng trnh.




2.4.1. Lp mt th nh vo CPU.

KHUYN CO

Nu ta lp mt th nh (th nh c cu hnh nh mt th chng trnh hay mt th

chuyn) vo trong mt CPU ang chy, CPU chuyn sang ch STOP ngay lp tc. Cc

thit b iu khin c th ri vo mt iu kin khng an ton, gy nn s vn hnh khng

mong mun ca thit b c iu khin. Cc vn hnh khng mong mun c th gy t

vong hay tn thng nghim trng n con ngi, v/hoc gy ph hy thit b. Lun lun

lp t mch dng khn cp cho ng dng hay quy trnh.

CH

Hin tng np tnh in c th ph hy th nh hay ni cm trn CPU.

Thc hin vic tip xc vi mt tm c ni t v/hoc eo mt vng dy c tay c

ni t khi ta cm th nh. Ct th nh trong mt hp cha c tnh dn in.

lp mt th nh, ta m tm che pha trn ca CPU v lp th nh vo trong

rnh. Kiu kt ni nhn nhn cho php ta lp vo v ly ra mt cch d dng. Th

nh c kha li nu ta lp vo ng cch.

Cn kim tra rng th nh khng c bo v ghi. Trt cng tc bo v ra

khi v tr Lock.




Ch

Nu ta lp vo th nh khi CPU trong ch STOP, b m chn on s

hin th mt thng ip m s nh tr th nh c khi chy. Hy ng lu tm

n thng ip ny. S nh tr th nh s khng khi ng cho n khi ta chuyn

CPU sang ch RUN, hoc t li b nh CPU bng mt lnh MRES, hay n chu

trnh cp ngun cho CPU.




2.4.2. Cu hnh cc thng s khi ng cho CPU trc khi sao chp n n th

nh.

Khi ta sao chp mt chng trnh n th chuyn hay th chng trnh, chng

trnh s bao gm cc thng s khi ng cho CPU. Trc khi sao chp chng trnh

vo th nh, lun lun chc chn rng ta cu hnh ch vn hnh cho CPU theo

mt chu trnh cp ngun. La chn khi no CPU khi ng trong ch STOP, ch

RUN hay trong ch trc (trc chu trnh cp ngun).




2.4.3. Th chuyn.

CH




To ra mt th chuyn

Lun lun nh cu hnh thng s khi ng ca CPU trc khi sao chp mt

chng trnh n th chuyn. to ra mt th chuyn, lm theo cc bc sau y:

1. Lp mt th nh trng vo trong b c/b ghi th c gn km vi thit b lp

trnh.

(Nu khng phi l th nh trng, ta xa th mc SIMATIC.S7S v tp tin

S7_JOB.S7S trn th nh bng cch s dng mt ng dng v d nh Windows

Explorer.)

2. Trong Project tree (kiu xem Project), m rng th mc SIMATIC Card Reader

v la chn th nh.

3. Hin th hp thoi Memory card bng cch nhp chut phi ln th nh trong b

c th v la chn Properties t trnh n ng cnh.

4. Trong hp thoi Memory card, la chn Transfer t trnh n th xung.

Ti y, phn mm STEP 7 Basic to ra mt th chuyn trng. Nu ta to ra

mt th chuyn trng, v d nh khi phc t mt mt khu CPU b mt, hy ly

th chuyn ra khi b c th.




5. Thm chng trnh bng cch la chn thit b CPU (v d nh PLC_1 [CPU 1214

DC/DC/DC]) trong Project tree v ko thit b CPU n th nh. (Mt phng php

khc l sao chp thit b CPU v dn vo th nh). Vic sao chp thit b CPU n th

nh s m ra hp thoi Load preview.

6. Trong hp thoi Load preview, nhp vo nt Load sao chp thit b CPU n

th nh.

7. Khi hp thoi hin th mt thng ip rng thit b CPU (chng trnh) c np

m khng xy ra li, ta nhp vo nt Finish.

S dng mt th chuyn

chuyn chng trnh n mt CPU, ta lm theo cc bc sau:

1. Lp th chuyn vo trong CPU. Nu CPU ang ch RUN, CPU s chuyn sang

ch STOP. (LED bo dng nhp nhy ch th rng th nh cn c nh tr.)

2. S dng mt trong cc ty chn sau nh tr cho th nh:

- Chu trnh cp ngun CPU.

- Thc hin mt s chuyn i t STOP sang RUN.

- Thc hin mt s t li b nh (MRES).




3. Sau khi khi ng li v nh tr th nh, CPU s sao chp chng trnh vo b nh

np bn trong ca CPU. Khi hot ng sao chp hon tt, CPU nhp nhy LED bo

dng ch th rng th chuyn c th c ly ra.

4. Ly th chuyn ra khi CPU.

5. S dng mt trong s cc ty chn sau nh tr chng trnh mi c chuyn

n b nh np bn trong:




CPU sau s chuyn sang ch khi ng (RUN hay STOP) m ta cu

hnh cho n.

Lu

Ta phi ly th chuyn ra trc khi thit lp CPU sang ch RUN.




2.4.4. Th chng trnh.

CH




Kim tra rng th nh khng c bo v ghi. Trt

cng tc bo v ra khi v tr Lock.

Trc khi sao chp bt k cc phn t chng trnh

vo th chng trnh, ta phi xa cc chng trnh

c lu trc ra khi th nh.

To ra mt th chng trnh

Khi c s dng vi vai tr l mt th chng tnh, th nh tr thnh b nh np

ngoi vi ca CPU. Nu ta ly th chng trnh ra, b nh np bn trong ca CPU s

trng rng.

Lu

Nu ta lp mt th nh trng vo trong CPU v thc hin nh tr th nh bng

chu trnh cp ngun cho CPU, bng vic thc hin mt chuyn i t STOP sang

RUN, hay thc hin mt s t li b nh (MRES), chng trnh v cc gi tr p buc

trong b nh np bn trong ca CPU s c sao chp n th nh. (Th nh by gi

l mt th chng trnh.) Sau khi vic sao chp hon tt, chng trnh trong b nh

np bn trong ca CPU s b xa. CPU s chuyn sang ch khi ng c cu

hnh (RUN hay STOP).




Lun lun nh cu hnh thng s khi ng ca CPU trc khi sao chp mt

chng trnh n th chng trnh. to ra mt th chng trnh vi STEP 7 Basic,

lm theo cc bc sau y:

1. Lp mt th nh trng vo trong b c/b ghi th c gn km vi thit b lp

trnh.

(Nu khng phi l th nh trng, ta xa th mc SIMATIC.S7S v tp tin

S7_JOB.S7S trn th nh bng cch s dng mt ng dng v d nh Windows

Explorer.)

2. Trong Project tree (kiu xem Project), m rng th mc SIMATIC Card Reader

v la chn th nh.

3. Hin th hp thoi Memory card bng cch nhp chut phi ln th nh trong b

c th v la chn Properties t trnh n ng cnh.

4. Trong hp thoi Memory card, la chn Program t trnh n th xung.

Ti y, phn mm STEP 7 Basic to ra mt th chuyn trng. Nu ta to ra

mt th chuyn trng, v d nh khi phc t mt mt khu CPU b mt, hy ly

th chuyn ra khi b c th.




5. Thm chng trnh bng cch la chn thit b CPU (v d nh PLC_1 [CPU 1214

DC/DC/DC]) trong Project tree v ko thit b CPU n th nh. (Mt phng php

khc l sao chp thit b CPU v dn vo th nh). Vic sao chp thit b CPU n th

nh s m ra hp thoi Load preview.

6. Trong hp thoi Load preview, nhp vo nt Load sao chp thit b CPU n

th nh.

7. Khi hp thoi hin th mt thng ip rng thit b CPU (chng trnh) c np

m khng xy ra li, ta nhp vo nt Finish.

S dng mt th chng trnh nh b nh np cho CPU

CH

Nu ta lp mt th nh vo trong mt CPU, CPU s chuyn sang ch STOP. Nu ta thc

hin chu trnh cp ngun cho CPU, thay i CPU t ch STOP sang RUN, hay t li b

nh CPU (MRES), CPU s sao chp b nh np bn trong n th nh (cu hnh th nh

nh l mt th chng trnh) v xa i chng trnh khi b nh np bn trong. Nu ta ly

th chng trnh ra, CPU s khng c chng trnh trong b nh np bn trong.

s dng mt th chng trnh vi CPU, ta lm theo cc bc sau:

1. Lp th chng trnh vo trong CPU. Nu CPU ang ch RUN, CPU s

chuyn sang ch STOP. LED bo dng nhp nhy ch th rng th nh cn

c nh tr.

2. S dng mt trong cc ty chn sau nh tr cho th nh:




3. CPU s t ng khi ng li. Sau khi khi ng li v nh tr th chng trnh,

CPU xa i b nh np bn trong.




CPU sau s chuyn sang ch khi ng (RUN hay STOP) m ta cu

hnh.

Th chng trnh phi gi nguyn trong CPU. Vic ly th chng trnh ra s

khng li trong b nh np bn trong CPU mt chng trnh no.

KHUYN CO

Nu ta ly th chng trnh ra, CPU s mt i b nh np ngoi vi ca n v sinh ra mt

li. CPU chuyn sang ch STOP v lm nhp nhy LED bo li.

Cc thit b iu khin c th ri vo mt iu kin khng an ton, gy nn s vn hnh

khng mong mun ca thit b c iu khin. Cc vn hnh khng mong mun c th

gy t vong hay tn thng nghim trng n con ngi, v/hoc gy ph hy thit b.


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