dieu khien logic giao trinh tap lenh - hoi

8/8/2019 Dieu Khien Logic Giao Trinh Tap Lenh - Hoi

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GIO TRNH TP LNH

PLC SIEMENS S7-200

ThS. Nguyn B Hii hc Nng - Trng i hc Bch khoa

[email protected]

Gio trnh y bao gm 3 phn:1. Gio trnh l thuyt2. Gio trnh tp lnh

3. Gio trnh bi tp
mailto:[email protected]:[email protected]


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MC LC

1. Lnh logic vi bit............................................................................................................. 4 1.1 Contact ............................................................................................................................................... 4

1.1.1 Cng tc ..................................................................................................................................... 41.1.2 Cng tc tc khc ...................................................................................................................... 4

1.1.3 Lnh o bit, lnh sn ............................................................................................................. 41.2 Coil...................................................................................................................................................... 61.2.1 Lnh ra ....................................................................................................................................... 61.2.2 Lnh ra tc khc......................................................................................................................... 61.2.3 Lnh Set, Reset.......................................................................................................................... 61.2.4 Lnh Set, Reset Immediat .......................................................................................................... 61.2.5 Lnh khng lm g c ................................................................................................................. 7

2. Lnh so snh ................................................................................................................... 8

3. Lnh chuyn i .............................................................................................................. 9

4. Lnh nh thi ............................................................................................................... 11

5. Lnh bm.................................................................................................................. 13

6. Lnh dch chuyn nh ............................................................................................... 15

7. Lnh vi Bng ............................................................................................................... 16 7.1 Lnh thm vo bng ....................................................................................................................... 167.2 Lnh Memory Fill............................................................................................................................. 177.3 Lnh tm kim trong bng .............................................................................................................. 17

8. Lnh ton s hc........................................................................................................... 19 8.1 Cng, Tr, Nhn, Chia s nguyn, s thc.................................................................................. 198.2 Lnh tng gim mt n v ............................................................................................................ 218.3 Cc lnh hm s hc ...................................................................................................................... 22

9. Lnh vng lp PID ......................................................................................................... 22

10. Lnh php ton logic .................................................................................................... 29 10.1 Lnh o byte, word, doubleword ............................................................................................ 2910.2 Lnh AND, OR, XOR ................................................................................................................... 29

11. Lnh dch v quay ......................................................................................................... 30 11.1 Dch tri hay phi ........................................................................................................................ 3011.2 Quay tri hay phi....................................................................................................................... 3111.3 Lnh dch thanh ghi cc bit (Shift Register Bit): ..................................................................... 3211.4 Lnh SWAP.................................................................................................................................. 33

12. Cc lnh iu khin chng trnh................................................................................ 33 12.1 END c iu kin ........................................................................................................................ 3312.2 STOP ............................................................................................................................................ 33

12.3 Lnh Watchdog Reset ................................................................................................................ 3412.4 Lnh nhy.................................................................................................................................... 3412.5 Lnh SCR..................................................................................................................................... 35

13. Lnh chng trnh con................................................................................................. 36

14. Lnh ngt ....................................................................................................................... 38


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Mt squinh khi tra cu lnh v sdng lnh:- Trn cng l phn tn lnh hoc nhm lnh.

- Tip theo l c php lnh, ln lt trong LAD, FBD v STL.- Di cng l nhng loi CPU S7-200 cho php s dng lnh, lu y ch bao gm 03 loi CPUmi: 221, 222 v 224.

- Bn cnh l phn m t hot ng ca lnh.


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Cc trng hp li l cc trng hp gy li khin u ra ENO = 0, bnh thng khi lnh c thc hin thENO = 1.

- Cc bit c bit trong vng SM c gi tr thay i ty theo kt qu thc hin lnh.- Bng cc ton hng ch ra cc thng s hp l ca lnh- Sau y l nhng k hiu khi g lnh trong STEP 7:

o Trong LAD: ---> ngha l c th ni tip lnh khc (nhng khng bt buc).o Trong LAD: --->> ngha l bt buc phi ni tip lnh khc.o Tn bin nm trong ngoc kp (v d var) l bin ton cc.o Tn bin c k hiu # ng trc l bin cc b.o K hiu ? hay ???? ngha l yu cu ton hng.o K hiu > yu cu hoc ton hng hoc ni lnh khc.o K hiu >I cho bit l u ra ENO.o K t % trc tn bin ngha l bin trc tip trong IEC.o Trong FBD, du trn nhu vo nh du o (nh trong in t); mt gch dc ngn

(|) u vo nh du gi tr tc khc (u vo trc tip).

1. Lnh logic vi bit

1.1 Contact

1.1.1 Cng tcCng tc thng m (Normally Open, vit tt l NO) v cng tc thngng (Normally Closed, vit tt l NC). i vi PLC, mi cng tc i dincho trng thi mt bit trong b nhd liu hay vng nh ca cc u vo,ra. Cng tc thng msng (ON - ngha l cho dng in i qua) khibit bng 1 cn cng tc thng ng sng (ON) khi bit bng 0.

Trong LAD, cc lnh ny c biu din bng chnh cc cng tc thngmv thng ng. Trong FBD, cc cng tc thng mc biu dinnh cc u vo hoc ra ca cc khi chc nng AND hoc OR. Cng tcthng ng c thm du o (vng trn nh) u vo tng ng.

Trong STL, cc cng tc thng mc s dng trong cc lnh LOAD,AND hoc OR. Lnh LOAD ghi gi tr bit c nh a ch bi ton hngca lnh vo nh ngn xp, nhng gi tr c trong ngn xp by xungmt bc (gi tr di cng s mt). Cc lnh AND v OR thc hin phpton logic AND hay OR gia gi trc trn bi ton hng vi nhngn xp, kt quc ghi vo nh ngn xp, nhng gi tr c trong ngnxp by xung mt bc. Hon ton tng ti vi cc cng tc thngng, c s dng trong cc lnh LOAD NOT, AND NOT v OR NOT(gi trc trn bi ton hng s bo).

1.1.2 Cng tc tc khcTrong STL, cc cng tc thng m tc khc c s dng trong cc lnhLOAD IMMEDIATE (ghi gi tru vo vt l vo nh ngn xp, nhng

gi tr c trong ngn xp by xung mt bc (gi tr di cng smt)),AND IMMEDIATE hoc OR IMMEDIATE (thc hin php ton l gic And hay Or gia gi tru vovt l vi nh ngn xp, kt quc ghi vo nh ngn xp, nhng gi tr c trong ngn xp by xungmt bc). Hon ton tng ti vi cc cng tc thng ng tc khc, c s dng trong cc lnhLOAD NOT IMMEDIATE, AND NOT IMMEDIATE v OR NOT IMMEDIATE (gi tru vo vt l bo).

1.1.3 Lnh o bit, lnh snLnh o thay i dng nng lng (Power Flow). Nu dng nng lng gp lnh ny, n s b chn li.Ngc li nu pha trc lnh ny khng c dng nng lng, n s tr thnh ngun cung cp dng nnglng. Trong LAD, lnh ny c biu din nh mt cng tc. Trong FBD, lnh o khng c biu tng

ring. N c tch hp nh l u vo o ca nhng khi chc nng khc (vi vng trn nhu voca cc khi chc nng ). Trong STL, lnh o o gi tr ca nh ngn xp: 0 thnh 1 v 1 thnh 0.Lnh ny khng c ton hng.


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Lnh sn: u thuc nhm lnh cc cng tc, ghi nhn trng thi cc bit d liu (0 hay 1), quen thuc vikhi nim mc. Cc lnh v sn ghi nhn khng phi mc n thun m l s bin i mc. Lnh sndng (Positive Transition) cho dng nng lng i qua trong khong thi gian bng thi gian mt vngqut khi u vo ca n c s thay i mc t 0 ln 1. Lnh sn m (Negative Transition) cho dngnng lng i qua trong khong thi gian bng thi gian mt vng qut khi u vo ca n c s thay imc t 1 xung 0.Trong LAD, cc lnh ny c biu din cng nh cc cng tc. Trong FBD, cc lnh ny c biu dinbng cc khi chc nng P v N. Trong STL, lnh Edge Up, nu pht hin c s thay i mc ca nhngn xp t 0 ln 1, st vo nh ngn xp gi tr 1. Trong trng hp ngc li, n t vo gi tr 0.Tng t, lnh Edge Down, nu pht hin c s thay i mc ca nh ngn xp t 1 xung 0, st vonh ngn xp gi tr 1. Trong trng hp ngc li, n cng t vo gi tr 0.

Ch : Theo cu trc hot ng ca PLC, s thay i mc tt nhin chc pht hin gia ccvng qut lin tip. Do mi lnh sn ny cn mt bit nh nhtrng thiu vo ca n vng qut k trc. Vc tnh ny m tng s lnh sn c sdng trong mt chng trnhbhn ch (do dung lng b nhdnh cho chng c hn).V d cho cc lnh NOT, P, N:


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1.2 Coil

1.2.1 Lnh raGi tr bit c nh a ch bi ton hng ca lnh ra phn nh trng thi cadng nng lng (Power Flow) u vo lnh ny. Trong LAD v FBD, lnhra t gi tr bit c trn bi ton hng ca n bng gi tr dng nnglng u vo ca lnh. Trong STL, lnh ra sao chp gi trnh ngn xpra gi tr bit c trn bi ton hng ca lnh.

1.2.2 Lnh ra tc khcGi tru ra ri rc (digital) vt l c nh a ch bi ton hng ca lnhra trc tip phn nh trng thi ca dng nng lng (Power Flow) u volnh ny. Trong LAD v FBD, lnh ra trc tip t ng thi gi tru ra vtl c trn bi ton hng ca n v bit nh ca u ra ny bng gi trdng nng lng u vo ca lnh. iu khc vi lnh ra thng thngch lnh ra thng thng ch ghi gi tr vo bit nh ca u ra. Trong STL,lnh ra trc tip sao chp gi trnh ngn xp ra ng thi gi tru ra vtl c trn bi ton hng ca lnh v bit nh ca u ra ny.

1.2.3 Lnh Set, ResetCc lnh SET v RESET t mt s cc bit lin ti p trong b nhd liuthnh 1 (Set) hay 0 (Reset). S lng cc bit c nh bi ton hng [N] vbt u t bit c nh a ch bi ton hng [bit]. S lng cc bit cth Set hoc Reset nm trong khong t 1 n 255. Trong trng hp s dnglnh Reset vi cc bit nm trong nhng vng T hay C, cc bnh thi hay

bm tng ng s b reset. Ngha l bit trng thi ca chng c a v 0 v sang m cng b xa(s c gi tr 0).

Nhng li c thc gy nn bi cc lnh ny (ENO = 0):+ Bitc bit SM4.3 = 1: li Run - Time.+ Li 0006: a chgin tip.+ Li 0091: ton hng vt qu gii hn cho php.

1.2.4 Lnh Set, Reset ImmediatCc lnh SET IMMEDIATE v RESET IMMEDIATE t mt s cc u ra ri rc (digital) vt l lin tipthnh 1 (Set) hay 0 (Reset). S lng cc u ra c nh bi ton hng [N] v bt u tu ra c nha ch bi ton hng [bit]. S lng cc u ra vt l c th Set hoc Reset nm trong khong t 1 n 12.K t I trong nhng lnh ny (Immediate) ni ln tnh tc thi. Cc lnh ny ghi gi tr mi ra cc u ravt l ng thi ghi c vo cc gi trnh ca chng. iu khc vi nhng lnh Set v Reset thngthng ch ghi gi tr mi vo vng nh ca cc u ra.


V d:


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1.2.5 Lnh khng lm g cLnh khng lm g (No Operation) khng tc ng n chng trnh. Mc d ncng c mt ton hng [N] dng Byte, l mt hng s trong khong t 1 n 255.


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2. Lnh so snh

So snh Byte: Lnh so snh Byte dng so snh 02 gi tr dng bytec nh a ch bi hai ton hng u vo ca lnh: [IN1] v [IN2].C tt c 06 php so snh c thc thc hin: [IN1] = [IN2], [IN1]>= [IN2], [IN1] [IN2], [IN1] < [IN2], [IN1] [IN2]. Cc byte c em so snh l nhng gi tr khng du. Trong

LAD, lnh ny c dng mt cng tc v cng tc ng (ON) khi iu kin em so snh c gi trng.Trong FBD, u ra s c gi tr 1 nu iu kin em so snh l ng. Trong STL, lnh c thc hin s ghigi tr 1 vo nh ngn xp (vi nhng lnh Load) hoc thc hin php ton l gic AND hay OR (ty theolnh c th) gi tr 1 vi nh ngn xp nu iu kin so snh ng.

So snh snguyn (Integer): Lnh so snh s nguyn dng so snh 02 gi tr dng Integerc nh

a ch bi hai ton hng u vo ca lnh: [IN1] v [IN2]. C tt c 06 php so snh c thc thchin: [IN1] = [IN2], [IN1] >= [IN2], [IN1] [IN2], [IN1] < [IN2], [IN1] [IN2].Cc s nguyn c em so snh l nhng gi tr c du: 16#7FFF > 16#8000.

So snh tkp (Double Word): Lnh so snh t kp dng so snh 02 gi tr dng Double Word cnh a ch bi hai ton hng u vo ca lnh: [IN1] v [IN2]. C tt c 06 php so snh c thcthc hin: [IN1] = [IN2], [IN1] >= [IN2], [IN1] [IN2], [IN1] < [IN2], [IN1] [IN2].Cc gi tr t kp c em so snh l nhng gi tr c du: 16#7FFFFFFF > 16#80000000.

So snh sthc (Real): Lnh so snh s thc dng so snh 02 gi tr dng Real c nh a ch bihai ton hng u vo ca lnh: [IN1] v [IN2]. C tt c 06 php so snh c thc thc hin: [IN1] =[IN2], [IN1] >= [IN2], [IN1] [IN2], [IN1] < [IN2], [IN1] [IN2]. Cc s thc cem so snh l nhng gi tr c du theo kiu du phy ng.

V d s dng lnh so snh:


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3. Lnh chuyn i

V d Round v Truncate:


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V d SEG (Segment):

Ngoi ra cn c cc lnh chuyn i sang m ASCII.


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4. Lnh nh thiSIMATIC S7-200 c 03 loi bnh thi:

- Bng tr(On - Delay Timer) TON- Bng trc nh(Retentive On - Delay Timer) TONR- B ngt tr(Off - Delay Timer) TOF

Cc bng tr v ng tr c nhbt u m thi gian khi c u

vo EN (Enable) mc 1 (ON). Lc gi trm c ln hn hocbng gi trt trc ti u vo PT (Preset Time) th bit trng thi sc t bng 1 (ON). iu khc nhau gia hai loi bng tr nyl: bng tr bnh thng s b reset (c gi trang m ln bit

trng thi u b xa v 0) khi u vo EN bng 0; trong khi bnh thi c nhlu li gi tr ca n khiu vo EN bng 0 v tip tc m nu u vo EN li bng 1. Nh vy ta c th dng loi c nh cngthi gian nhng lc u vo EN bng 1. Loi bnh thi ny c th reset (xa gi trang m v 0) bnglnh R (Reset). C hai loi bng tr vn tip tc m thi gian ngay c sau khi t n gi trt trcPT v ch dng m khi t gi tr ti a 32767 (16#7FFF).

B ngt tr dng a gi tru ra (bit trng thi) v 0 (OFF) tr mt khong thi gian sau khi u vo(EN) i v 0. Khi u vo EN c t bng 1 (ON) th bit trng thi ca b ngt tr cng bng 1 ngay lc ng thi gi trm ca n b xa v 0. Khi u vo EN v 0, bnh thi bt u m v m cho nkhi t gi trt trc PT. Lc bit trng thi ca b ngt tr s v 0 ng thi n cng ngng m. Nuu vo EN ch bng 0 trong khong thi gian ngn hn thi gian c t ri quay li bng 1 th bit trngthi ca bnh thi vn gi nguyn bng 1. B ngt tr ch bt u m khi c sn thay i t 1 thnh 0u vo EN.

Nu b ngt trtrong vng mt SCR(Sequence Control Relay) v vng SCR khng c kch hot thgi trm ca n c xa v 0, bit trng thi cng bng 0 (OFF) v bnh thi khng m. Khi nimvng SCR sc nh ngha phn sau ca ti liu ny.

Thi gian trc tnh nh l tch cagi trangm vi phn gii ca ca bnh thi.

Nhng bnh thi c nhc a chc qui nh ring. Nhng bnh thi cn li (khng nh) c thc khai bo nhl bng trhoc ngt tr, nhng khng thl c hai. V d khng thc TON 33 vTOF 33 ng thi.Bng sau tm tt nhng c im hot ng ca ba loi bnh thi nu trn:


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Lnh Reset (R) c thc s dng reset bt k bnh thi no. Cc bnh thi c nh(loi TONR)ch c th reset bng lnh ny. Cc bnh thi sau khi reset c bit trng thi cng nh gi trm uc xa v 0. Cc b ngt tr (TOF) ch bt u m khi c s thay i t 1 xung 0 u vo IN.

Cc bnh thi c phn gii khc nhau c cch hotng cng khc nhau. Chng ta xem xt khn vvn ny:

Bnh thi vi phn gii 1 ms:

Bnh thi loi ny m s khong thi gian 1 ms tri qua k t khi n c kch hot. Bnh thi vi phn gii 1 ms c kch hot bng lnh khai bo ca n nhng sau n c cp nht (bit trng thicng nh gi trm) mi giy mt ln mt cch c lp khng ph thuc vo vng qut chng trnh. Nimt cch khc, mt bnh thi loi ny c thc cp nht nhiu ln trong mt vng qut nu nh thigian vng qut ln hn 1 ms. Bi v mt bnh thi vi phn gii 1 ms c thc kch hot bt kmt thi im no trong vng 1 ms nn ta nn t gi trt trc ln hn 1 n v so vi gi tr yu cucn m. V dm khong thi gian 56 ms, ta thng t gi trt trc bng 57.

Bnh thi vi phn gii 10 ms:Bnh thi loi ny m s khong thi gian 10 ms tri qua k t khi n c kch hot. Bnh thi vi phn gii 10 ms c kch hot bng lnh khai bo ca n v sau n c cp nht (bit trng thicng nh gi trm) mi vng qut mt ln ngay u mi vng qut bng cch cng vo gi trang

m ca n s khong thi gian 10 ms tri qua k tu vng qut trc. Ni mt cch khc, gi trangm ca bnh thi loi ny gi nguyn khng i trong sut thi gian mt vng qut. Bi v mt bnhthi vi phn gii 10 ms c thc kch hot bt k mt thi im no trong vng 10 ms nn ta nnt gi trt trc ln hn 1 n v so vi gi tr yu cu cn m. V dm khong thi gian 140 ms,ta thng t gi trt trc bng 15.

Bnh thi vi phn gii 100 ms: Bnh thi loi ny tnh s khong thi gian 100 ms tri qua k tkhi n c cp nht ln cui. Lnh khai bo bnh thi vi phn gii 100 ms cp nht bit trng thicng nh gi trm ca n bng cch cng vo gi trang m ca n s khong thi gian 100 ms triqua k t vng qut trc. Nh vy, gi trang m ca bnh thi loi ny chc cp nht khi clnh khai bo n thc hin. V th nu bnh thi vi phn gii 100 ms c kch hot nhng lnhkhai bo n khng c thc hin trong mi vng qut th n c th khng c cp nht kp thi v mthiu thi gian. Ngc li nu lnh khai bo bnh thi c thc hin nhiu ln trong mt vng qut thn c thm d thi gian do mt s khong thi gian 100 ms c cng nhiu ln. Tm li nn s dngbnh thi loi ny vi lnh khai bo thc hin chnh xc mi vng qut mt ln. Bi v mt bnh thivi phn gii 100 ms c thc khi ng bt k mt thi im no trong vng 100 ms nn ta nnt gi trt trc ln hn 1 n v so vi gi tr yu cu cn m. V dm khong thi gian 2100ms, ta thng t gi trt trc bng 22.

hiu thm vcchcp nht ca cc bnh thi vi nhng phn gii khc nhau, chng ta xemxt v d sau, to bnh thi 3 giy vi ln lt ba bnh thi khc nhau (xem chng trnh kmtheo):

u tin bnh thi vi phn gii 1 ms c s dng (T32, gi trt trc 300). Q0.0 s c gi tr

bng 1 (ON) trong thi gian mt vng qut khi v ch khi no thi im cp nht ca bnh thi m gitrm vt qua gi trt trc ri vo ng gia lc thc hin hai lnh ny. Ngha l sau khi lnhtrc c thc hin nhng phi trc khi thc hin lnh sau.


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Nu s dng bnh thi vi phn gii 10 ms (T33, gi trt trc 30), Q0.0 khng bao gic gitr 1 (lun lun OFF).

Trng hp cui cng s dng bnh thi vi phn gii 100 ms (T37, gi trt trc bng 3). Q0.0lun lun c gi tr bng 1 (ON) trong ng thi gian mt vng qut.

m bo chc chn Q0.0 s c gi tr 1 (ON) trong thi gian mt vng qut, ta phi dng cng tcthng ng Q0.0 kch hot cc bnh thi thay v dng cng tc thng ng vi bit trng thi can.

5. Lnh bmBa loi bm: bm ln (Count Up), bm xung (Count Down)

v loi bm c th va m ln va m xung (Count Up / Down).

Bm ln m cho n gi tr ti a ca n (32767) mi khi c snln u vo m ln (CU). Khi gi trm (Cxxx) ln hn hoc bnggi trt trc (PV) th bit trng thi (Cxxx) s c gi tr 1 (ON). Bm c th b xa (reset) bi mc 1 u vo reset (R), lc c gi trm ln bit trng thi s b xa v 0.

Bm xung m t gi trt trc (PV) mi khi c sn ln uvo m xung (CD). Khi gi tr m (Cxxx) bng 0, bit trng thi(Cxxx) s bng 1 ng thi bm ngng m. Mc cao u vo LDxa bit trng thi v 0 v ti gi trt trc PV vo gi trm.

Bm va m ln va m xung m ln khi c sn ln u vom ln (CU) v m xung khi c sn ln u vo m xung(CD). Khi gi trm (Cxxx) ln hn hoc bng gi trt trc (PV)th bit trng thi (Cxxx) s c gi tr 1 (ON). B m c th b xa(reset) bi mc 1 u vo reset (R), lc c gi trm ln bit trng

thi s b xa v 0.

S hiu cc bm: C0 n C255. Trong CPU 221, 222 v 224 mi bm c xc nh loi ty theolnh khai bo nhng khng th khai bo cc bm loi khc nhau vi cng mt a ch (trong vng C).

Trong STL, u vo reset (R) ca bm tin l bit nh ca ngn xp v u vo m ca n (CU) l bitth hai ca ngn xp. Trong STL, u vo ti (LD) ca bm li l bit nh ca ngn xp v u vo mca n (CD) l bit th hai ca ngn xp. Trong STL, u vo reset (R) ca bm va m tin va m


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li l bit nh ca ngn xp, u vo m li ca n (CD) l bit th hai ca ngn xp v u vo m tinca n (CU) l bit th ba ca ngn xp.

Cc bm cn c th b reset bi lnh Reset. Bm va tin va li khi m n gi tr ti a (32767)m tip tc m ln thi sm s nhy sang gi tr ti thiu (-32768) v tip tc m bnh thng. Tngt, nu n m li khi gi tr nh nht (-32768) th sm s nhy thnh gi tr ln nht (32767).

V d s dng bm:


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Cc bm tc cao xem gio trnh l thuyt.

6. Lnh dch chuyn nhCc lnh dch chuyn mt Byte, mt t n (Word), mt t kp(Double Word) hay mt sthc (Real):

Lnh dch chuyn mt Byte, Move Byte, sao chp ni dung nhkchthc mt byte c nh a chu vo IN ln nhkch thc mtbyte c nh a chu ra OUT. Ni dung byte nha ch [IN]khng thay i. Tng t cho cc cu lnh vi W, DW.Lnh dch chuyn mt S thc, Move Real, sao chp s thc kch thc32 bit c nh a chu vo IN ln s thc kch thc 32 bit cnh a chu ra OUT. S thc a ch [IN] khng thay i.

Nhng li c thc gy nn bi cc lnh ny (ENO = 0):+ Bitc bit SM4.3 = 1: li Run - Time.+ Li 0006: a chgin tip.

Cc lnh dch chuyn mt Byte, mt tn (Word) tc khc: c hocghi.

Lnh dch chuyn mt khi cc byte, Block Move Byte: sao chp nidung mt s cc nh lin tip (xc nh bi ton hng u vo N),mi kch thc mt byte vi byte u tin c nh a chu vo

IN ln khi cc nh lin tip kch thc mi nhmt byte v byteu tin c nh a chu ra OUT. S lng cc byte c th saochp nm trong khong t 1 n 255.Lnh dch chuyn mt khi cc tn, Block Move Word, sao chp ni


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dung mt s cc nhlin tip (xc nh bi ton hng u vo N), mi kch thc mt word vi wordu tin c nh a chu vo IN ln khi cc nh lin tip kch thc mi nhmt word vword u tin c nh a chu ra OUT. S lng cc word c th sao chp nm trong khong t 1n 255.

Lnh dch chuyn mt khi cc t kp, Block Move Double Word, sao chp ni dung mt s cc nhlintip (xc nh bi ton hng u vo N), mi kch thc mt t kp vi t kp u tin c nh achu vo IN ln khi cc nhlin tip kch thc mi nhmt t kp v t kp u tin c nha chu ra OUT. S lng cc t kp c th sao chp nm trong khong t 1 n 255.


7. Lnh vi Bng

7.1 Lnh thm vo bng


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7.2 Lnh Memory Fill

Lnh ny in y mt khong nhbao gm mt s cc tn lin tip(c xc nh bi u vo N) vi tn (Word) u tin c nh ach bi u ra OUT bng tn c nh a chu vo IN. Kchthc khong nhc th nm trong khong t 1 n 255 tn.Nhng li c thc gy nn bi lnh ny (ENO = 0):+ Bitc bit SM4.3 = 1: li Run - Time.+ Li 0006: a chgin tip.+ Li 0091: ton hng vt qu gii hn cho php.

V d:

7.3 Lnh tm kim trong bng


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8. Lnh ton s hc

8.1 Cng, Tr, Nhn, Chia s nguyn, s thc

Cc lnh ny cng (Add) hay tr (Subtract) hai s nguyn c nh achcc u vo IN1 v IN2, kt qu lu vo s nguyn c nh ach bi u ra OUT.

[IN1] + [IN2] = [OUT][IN1] - [IN2] = [OUT]

Nhng li c thc gy nn bi lnh ny (ENO = 0):+ Bitc bit SM4.3 = 1: li Run - Time.+ Li 0006: a chgin tip.+ Bitc bit SM1.1 = 1: li trn (Overflow).Nhng bit nhc bit c ni dung bnh hng bi lnh ny:

+ SM1.0 (Zero): bng 1 nu kt qu bng 0.+ SM1.1 (Overflow): bng 1 nu kt qu b trn.+ SM1.2 (Negative): bng 1 nu kt qu l sm.

Cc lnh ny cng (Add) hay tr (Subtract) hai s nguyn 32 bit c nh a chcc u vo IN1 vIN2, kt qu lu vo s nguyn 32 bit c nh a ch bi u ra OUT.

[IN1] + [IN2] = [OUT][IN1] - [IN2] = [OUT]

Nhng li c thc gy nn bi lnh ny (ENO = 0):+ Bitc bit SM4.3 = 1: li Run - Time.


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+ Li 0006: a chgin tip.+ Bitc bit SM1.1 = 1: li trn (Overflow).Nhng bit nhc bit c ni dung bnh hng bi lnh ny:+ SM1.0 (Zero): bng 1 nu kt qu bng 0.+ SM1.1 (Overflow): bng 1 nu kt qu b trn.+ SM1.2 (Negative): bng 1 nu kt qu l sm.

Cc lnh nhn (Multiply) hay chia (Divide) hai s nguyn 16 bitc nh a chcc u vo IN1 v

IN2, kt qu lu vo s nguyn c nh a ch bi u ra OUT. Trong php chia, s d b b qua. Bitbo trn s thnh 1 nu kt qu ln hn mt s nguyn 16 bit. Nhng lnh ny khng c trong cc CPU212, 214.

[IN1] * [IN2] = [OUT]

[IN1] / [IN2] = [OUT]Nhng li c thc gy nn bi lnh ny (ENO = 0):+ Bitc bit SM4.3 = 1: li Run - Time.+ Li 0006: a chgin tip.+ Bitc bit SM1.1 = 1: li trn (Overflow).+ Bitc bit SM1.3 = 1: li chia cho 0 (Divide-by-zero).Nhng bit nhc bit c ni dung bnh hng bi lnh ny:+ SM1.0 (Zero): bng 1 nu kt qu bng 0.+ SM1.1 (Overflow): bng 1 nu kt qu b trn.+ SM1.2 (Negative): bng 1 nu kt qu l sm.+ SM1.3 (Divide-by-zero): bng 1 nu schia bng 0.Trong trng hp bit SM1.1 (Overflow) bng 1, kt qu skhngc ghi v cc bitc bit khc lin quann cc php ton (Zero, Negative, ...) u c xa v0.Trong trng h p bit SM1.3 (Divide-by-zero) bng 1, cc bit c bit khc lin quan n cc php ton(Zero, Negative, ...) u c ginguyn khng thay i v cc ton hngu vo cng khngi.Trong cc trng hp cn li, cc bitc bit ni trn sc gi tr phn nh trng thi ca kt qu theo tnhnng ca chng

Cc lnh nhn (Multiply) hay chia (Divide) hai s nguyn 32 bitc nh a chcc u vo IN1 vIN2, kt qu lu vo s nguyn 32 bit c nh a ch bi u ra OUT. Trong php chia, s d b b qua.Bit bo trn s thnh 1 nu kt qu ln hn mt s nguyn 32 bit. Nhng lnh ny khng c trong cc CPU

212, 214.[IN1] * [IN2] = [OUT][IN1] / [IN2] = [OUT]

Nhng li c thc gy nn bi lnh ny (ENO = 0):+ Bitc bit SM4.3 = 1: li Run - Time.+ Li 0006: a chgin tip.+ Bitc bit SM1.1 = 1: li trn (Overflow).+ Bitc bit SM1.3 = 1: li chia cho 0 (Divide-by-zero).Nhng bit nhc bit c ni dung bnh hng bi lnh ny:+ SM1.0 (Zero): bng 1 nu kt qu bng 0.+ SM1.1 (Overflow): bng 1 nu kt qu b trn.+ SM1.2 (Negative): bng 1 nu kt qu l sm.+ SM1.3 (Divide-by-zero): bng 1 nu schia bng 0.

Trong trng hp bit SM1.1 (Overflow) bng 1, kt qu skhngc ghi v cc bitc bit khc lin quann cc php ton (Zero, Negative, ...) u c xa v0.Trong trng h p bit SM1.3 (Divide-by-zero) bng 1, cc bit c bit khc lin quan n cc php ton(Zero, Negative, ...) u c ginguyn khng thay i v cc ton hngu vo cng khngi.

Cc lnh Nhn, Chia hai s nguyn (Integer) v ghi kt qu vo s nguyn di (Double Integer): Cclnh ny nhn (Multiply) hay chia (Divide) hai s nguyn 16 bit c nh a chcc u vo IN1 vIN2, kt qu lu vo s nguyn 32 bit c nh a ch bi u ra OUT. Trong php chia, kt qu bao gms d16 bit cao v thng s16 bit thp.

[IN1] * [IN2] = [OUT][IN1] / [IN2] = [OUT]

Trong STL, lnh MUL ch s dng 16 bit thp ca t kp [OUT] lm s nhn. Tng t lnh DIV cng ch

s dng 16 bit thp ca t kp [OUT] lm s b chia.Nhng li c thc gy nn bi lnh ny (ENO = 0):+ Bitc bit SM4.3 = 1: li Run - Time.+ Li 0006: a chgin tip.


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+ Bitc bit SM1.1 = 1: li trn (Overflow).+ Bitc bit SM1.3 = 1: li chia cho 0 (Divide-by-zero).Nhng bit nhc bit c ni dung bnh hng bi lnh ny:+ SM1.0 (Zero): bng 1 nu kt qu bng 0.+ SM1.1 (Overflow): bng 1 nu kt qu b trn.+ SM1.2 (Negative): bng 1 nu kt qu l sm.+ SM1.3 (Divide-by-zero): bng 1 nu schia bng 0.Trong trng h p bit SM1.3 (Divide-by-zero) bng 1, cc bit c bit khc lin quan n cc php ton

(Zero, Negative, ...)

u

c gi

nguyn khng thay

i v cc ton hng

u vo cng khng

i.

Cc sthc c biu din bng 32 bit di dng du phy ng theo chun ANSI / IEEE 754 - 1985.

Cc v d:

8.2 Lnh tng gim mt n v


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Thm vo hay bt i mt n v t mt Byte c nh a chu voIN, kt qu lu vo Byte c nh a ch bi u ra OUT. Cc s trongByte ton hng c xem l cc s khng du.

[IN] + 1 = [OUT]

[IN] - 1 = [OUT]Nhng li c thc gy nn bi lnh ny (ENO = 0):+ Bitc bit SM4.3 = 1: li Run - Time.+ Li 0006: a chgin tip.

+ Bitc bit SM1.1 = 1: li trn (Overflow).Nhng bit nhc bit c ni dung bnh hng bi lnh ny:

+ SM1.0 (Zero): bng 1 nu kt qu bng 0.+ SM1.1 (Overflow): bng 1 nu kt qu b trn.

Tng ti vi W, DW.

8.3 Cc lnh hm s hc

9. Lnh vng lp PIDLnh ny tnh ton vng lp PID (PID Loop) theo cc u vo v nhng thng s t bng c nh a chbi TBL.

Nhng li c thc gy nn bi lnh ny (ENO = 0):+ Bitc bit SM4.3 = 1: li Run - Time.+ Li 0006: a chgin tip.+ Bitc bit SM1.1 = 1: li trn (Overflow).Nhng bit nhc bit c ni dung bnh hng bi lnh ny:+ SM1.1 (Overflow): bng 1 nu kt qu b trn.

Lnh PID Loop (Proportional, Integral, Derivative Loop) c s dng tnh ton vng lp PID. Lnhny chc thc hin nu nhnh ca ngn xp (Top Of Stack) bng 1 trong STL, hay c Power Flowtrong LAD. Lnh ny c hai ton hng: [TBL] l a ch byte u tin ca mt bng d liu cn [LOOP] lmt s nm trong khong t 0 n 7. iu ny cng c ngha l ch c ti a 8 lnh PID Loop c thc


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s dng trong mt chng trnh. Nu c hai lnh PID Loop vi cng mt s [LOOP] th d chng c sdng hai bng khc nhau i na cng vn nh hng n nhau v c th gy nhng hu qu khng lngtrc c.

Bng d liu ca lnh PID Loop bao gm 09 tham s dng iu khin hot ng ca vng lp: gi tr tcthi v gi tr k trc (current and previous value) ca bin iu khin (process variable), gi tr yu cu(setpoint), gi tr x l (output - u ra ca PID), h s khuch i (gain), thi gian ly mu (sample time),h s tch phn (integral time - reset), h s vi phn (derivative time - rate) v integral sum (bias).

thc hin lnh ny mt tn sut ly mu xc nh, n phi hoc l c t trong mt ngt thi gianhoc l c thc hin trong chng trnh chnh qua kim sot bi mt bnh thi. ng thi, thi gianly mu tng ng phi c a vo bng d liu ca lnh.

Trong STEP 7 Micro / Win 32, chng ta c th s dng PID Wizard to thut ton vi PID cho mtmch iu khin kn bng cch chn Tools Instruction Wizard -> PID tMenu chnh.

trng thi n nh, mt biu khin PID siu chnh sao cho sai s gia gi tr yu cu (setpoint SP)v gi triu khin (process variable PV) bng 0. Nguyn l ca mt biu khin PID nh vy th hintrong phng trnh sau:

dtdeKdMiedtKieKctM

t

***)(0

+++=

output = proportional + integral + differentialtrong :

M(t): u ra ca PID (i lng x l) nh mt hm theo thi gianKc: hng s khuch ie: sai s. e = SP - PVMi: gi tr ban u ca PIDNhm mc ch p dng biu khin PID trn my vi tnh hay PLC ni ring v trong k thut s

ni chung, chng ta phi tin hnh ri rc ha phng trnh nu trn. C th l ly mu v lng t hacc bin. Phng trnh c vit li nh sau:

)(*** 11

-=

-+++= nnn

i

inn eeKdMieKieKcM


Mn: u ra ca PID (i lng x l) thi im ly mu nKc: hng s khuch ien: sai sthi im ly mu n. en = SPn - PVnen-1: sai sthi im ly mu ngay trc (n-1). en-1 = SPn-1 - PVn-1Ki: hng s khuch i ca thnh phn tch phnMi: gi tr ban u ca PIDKd: hng s khuch i ca thnh phn vi phn

T phng trnh ny ta nhn thy rng, nu nh thnh phn t l (proportional) ch l hm ca sai sthi im ly mu th thnh phn vi phn (differential) l hm s ca sai sthi im ly mu ln thiim ly mu k trc cn thnh phn tch phn (integral) li l hm ca tt c cc sai s t thi im lymu u tin cho n thi im ly mu hin ti. Trong k thut s, lu li tt c cc sai s l iu khngth thc hin c, cng nh tht s khng cn thit.

V gi tr x l lun c tnh ton mi thi im ly mu, k t thi im u tin, nn ch cnlu li gi tr k trc ca sai s v thnh phn tch phn. Phng trnh c n gin thnh:

)(*** 1--+++= nnnnn eeKdMXeKieKcM


Mn: u ra ca PID (i lng x l) thi im ly mu nKc: hng s khuch ien: sai sthi im ly mu n. en = SPn - PVnen-1: sai sthi im ly mu ngay trc (n-1). en-1 = SPn-1 - PVn-1Ki: hng s khuch i ca thnh phn tch phn


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MX: gi tr thnh phn tch phn thi im ly mu k trc (n-1)Kd: hng s khuch i ca thnh phn vi phnMt cch vit khc ca phng trnh:Mn = MPn + MIn + MDn


Mn: u ra ca PID (i lng x l) thi im ly mu nMPn: thnh phn t l ca u ra PID thi im ly mu nMIn: thnh phn tch phn ca u ra PID thi im ly mu nMDn: thnh phn vi phn ca u ra PID thi im ly mu nTa ln lt xt n tng thnh phn mt ca i lng x l:

Thnh phn t l (proportional) MP l tch ca hng s khuch i Kc vi sai s e. Trong Kc c trngcho nhy ca u ra PID (Kc cng ln, biu khin PID cng nhy) cn e l sai s gia i lng yucu (setpoint SP) v i lng thc t (process variable PV). Phng trnh biu din:

MPn = Kc * (SPn - PVn)trong :

MPn: thnh phn t l ca u ra PID thi im ly mu nKc: hng s khuch i

SPn: i lng yu cu ti thi im ly mu nPVn: i lng thc t ti thi im ly mu n

Thnh phn tch phn (integral) MI t l vi tng cc sai s qua thi gian, th hin bng phngtrnh:MIn = KC* Ts/ Ti* (SPn- PVn) + MXtrong :

MIn: thnh phn tch phn ca u ra PID thi im ly mu nKc: hng s khuch iTs: thi gian ly muTi: h s tch phnSPn: i lng yu cu ti thi im ly mu n

PVn: i lng thc t ti thi im ly mu nMX: gi tr ca thnh phn tch phn thi im ly mu k trc (n-1), cn c gi l integralsum hay bias.

Sau khi tnh ton gi tr MIn, bias MX c thay th bi chnh gi tr MIn vi kh nng c th biu chnh hoc ct (chn gii hn), iu ny sc ni r phn sau. Gi tr ban u ca bias MX, Mithng c ly l gi tr ca u ra b PID ngay trc thi im thc hin lnh PID ln u tin. Cc hngs khc nh hng n thnh phn ny l: Kc - hng s khuch i, Ts - thi gian ly mu v Ti - h s tchphn l c trng cho nh hng ca thnh phn ny ln ton bi lng x l.

Thnh phn vi phn (differential) MD t l vi thay i ca sai s, th hin qua phng trnh:MDn = KC* Td/ Ts* ((SPn - PVn ) - (SPn - 1 - PVn - 1 ))

Vi c tnh c qun tnh ca mi h vt cht, chng ta c th gi thit rng i lng thc t PV khng baogic s thay i mt cch gin on. Tuy nhin i lng yu cu th c th tng gim gy khc (do ctnh trn l thuyt). V bn cht ton hc, thnh phn vi phn l php ly o hm nn nhng s thay igin on c th gy nn cc gi tr v cng ln u ra. trnh hin tng ny, trong phng trnh trnta gi thit SPn = SPn - 1 v c th vit:

MDn = KC* Td/ Ts* (PVn - 1 - PVn)trong :

MDn: thnh phn vi phn ca u ra PID thi im ly mu nKc: hng s khuch iTs: thi gian ly muTd: h s vi phnSPn: i lng yu cu ti thi im ly mu nSPn-1: i lng yu cu ti thi im ly mu n-1PVn: i lng thc t ti thi im ly mu nPVn-1: i lng thc t ti thi im ly mu n-1


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Nh vy trn thc t khng cn nhsai sthi im ly mu k trc m ch cn nhi lngthc t. Trong ln tnh ton u tin PVn-1 c ly bng PVn.

Ty theo ng dng thc t, c th b bt thnh phn trong biu khin PID ch khng nht thitphi bao gm c ba thnh phn, chng hn c th to biu khin t l (P) hay biu khin ch chacc thnh phn t l v tch phn (PI). S la chn ny da trn cch t cc tham s.

Nu mun b thnh phn tch phn (b I), ta chn h s tch phn bng v cng (Ti = (). Trongtrng hp ny, thnh phn tch phn vn khng nht thit bng khng m c th bng mt gi tr khngi thng qua gi tr bias MX ban u.

Nu mun b thnh phn vi phn (b D), ta chn h s vi phn bng khng (Td = 0.0).Nu mun b thnh phn t l (b P), ta chn h s khuch i bng khng (Kc = 0.0). Trong trng hpny, v cc hng s ca cc thnh phn tch phn v vi phn c tnh theo Kc nn i vi nhng thnh phny, Kc c hiu l bng 1.0.

Mt biu khin PID c hai u vo: i lng yu cu v i lng thc t. y l nhng ilng tht trong ng dng nh nhit , p sut, tc , ... a vo tnh ton trong mt biu khin,chng phi c o, chuyn i v gi tr thch hp v chun ha (nu cn). Cc bc ny u cn thit chomt biu khin PID, b ny i hi cc gi tru vo l nhng gi tr s thc (du phy ng) nmtrong khong t 0.0 n 1.0.

Thng thng, nhng gi tro c c a vo PLC qua cc u vo tng t (qui vin ptrong khong 0 - 10VDC hoc dng in 0 - 20mADC) thnh nhng gi tr s nguyn 16 bit c du. Trcht nhng gi tr ny phi c i thnh cc s thc 32 bit (du phy ng), chng hn theo thut ton sau:XORD AC0, AC0 //Clear the accumulator.

MOVW AIW0, AC0 //Save the analog value in the accumulator.LDW>= AC0, 0 //If the analog value is positive,JMP 0 //then convert to a real number. NOT //Else,ORD 16#FFFF0000, AC0 //sign extend the value in AC0.LBL 0DTR AC0, AC0 //Convert the 32-bit integer to a real number.

Bc tip theo l chun ha v khong [0.0 - 1.0] theo phng trnh:

NNorm = (NRaw / Span) + Offsettrong :

NNorm l gi tr chun ha, i din cho mt i lng thtNRaw l gi tr thc cha chun ha, i din cho mt i lng thtSpan l hiu ca gi tr ln nht c th c tri gi tr nh nht c th c ca gi tr cha chun

ha. Trong S7-200 thng l 32000 - 0 = 32000 i vi cc i lng khng i du (unipolar) v khi Offset = 0.0, hay 32000 - (-32000) = 64000 i vi cc i lng c th va c gi tr dng va c gi trm (bipolar) v khi Offset = 0.5.

on lnh sau y minh ha cho thut ton ny trong trng hp i lng c du (bipolar):/R 64000.0, AC0 //Normalize the value in the accumulator+R 0.5, AC0 //Offset the value to the range from 0.0 to 1.0MOVR AC0, VD100 //Store the normalized value in the loop TABLE

Mt cch l gic chng ta thy rng cn phi c qu trnh ngc li vi qu trnh trn i vi gi tru ra ca biu khin PID. Ngha l bin i v a v thang gi tr thch hp cho u ra t gi trura chun ha trong khong 0.0 n 1.0. Phng trnh thut ton:

RScale = (MNorm - Offset) * Spantrong :

RScale l gi tr thch hp cho u ra, i din cho mt i lng thtMNorm l gi tru ra chun ha, i din cho mt i lng thtSpan l hiu ca gi tr ln nht c th c tri gi tr nh nht c th c ca gi tr cha chun

ha. Trong S7-200 thng l 32000 - 0 = 32000 i vi cc i lng khng i du (unipolar) v khi Offset = 0.0, hay 32000 - (-32000) = 64000 i vi cc i lng c th va c gi tr dng va c gi trm (bipolar) v khi Offset = 0.5.

on lnh minh ha cho thut ton:MOVR VD108, AC0 //Move the loop output to the accumulator.-R 0.5, AC0 //Include this statement only if the value is


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//bipolar.*R 64000.0, AC0 //Scale the value in the accumulator.ROUND AC0 AC0 //Convert the real number to a 32-bit integer.MOVW AC0, AQW0 //Write the 16-bit integer value to the analog

//output.

Chng ta thng ni v vng lp iu khin thun khi h s khuch i dng (Kc > 0) hay vnglp iu khin o (nghch) khi h s khuch i m (Kc < 0). Trong trng hp khng c thnh phn P(Kc = 0), ta xt du ca cc h s Ti v Td.

Cc gi tr yu cu v gi tr thc t (bin iu khin) l nhng u vo ca biu khin PID, do cc trng tng ng vi chng trong bng d liu ca PID s khng b thay i bi lnh ny.

Ngc li trng tng ng vi u ra c cp nht bi PID. N s b ct (chn) nu vt rangoi khong cho php [0.0 - 1.0].

Nu c s dng thnh phn tch phn (I), bias cng c cp nht v li c dng lm u vocho ln ly mu k tip. Tuy nhin n c thc iu chnh trong trng hp u ra b chn (v vt rangoi khong [0.0 - 1.0]) theo phng trnh sau:MX = 1.0 - (MPn + MDn )khi u ra ln hn 1.0, hay

MX = - (MPn + MDn )khi u ra nh hn 0.0, trong :MX l gi tr bias c iu chnhMPn l gi tr thnh phn t l (P) ca u ra thi im ly mu nMDn l gi tr thnh phn vi phn (D) ca u ra thi im ly mu nMn l gi tr ca u ra thi im ly mu n

Bng siu chnh ny, gi tru ra sc a v khong hp l. Gi tr biascng b chn trongkhong [0.0 - 1.0] v ghi vo bng d liu cho ln ly mu tip theo s dng.

Gi tr bias trong bng d liu c th thay i c ngay trc khi thc hin lnh PID nhng phich y l mt s thc nm trong khong [0.0 - 1.0].

Gi tri lng thc t ca ln ly mu trc c lu li trong bng d liu tnh ton thnhphn vi phn, khng bao gic thay i gi tr ny.

Mt biu khin PID c th hot ng mt trong hai ch: Auto hoc Manual. Thc ra khng c ch hot ng no c xy dng sn cho PID trong S7-200. S tnh ton chc thc hin khi c dngnng lng (powerflow) n u EN (enable) ca b PID. PID c xem nh hot ng ch Auto khin thc hin tnh ton mt cch tun hon lin tc. Trong trng hp ngc li, PID c xem nh hotng ch Manual. Vn chng ta cn xt n l s chuyn i m bo tnh lin tc t chManual sang ch Auto. iu i hi u ra c tnh trong ch Manual phi c ghi vo u vothi im chuyn i sang ch Auto. Tng t nh cch hot ng ca bm, CPU s dng mt bitnh xc nh thi im chuyn i: khi dng nng lng thay i t 0 ln 1. Lc CPU s thc hinmt lot thao tc cn thit:

t gi tr yu cu bng gi tr thc t: SPn = PVnt gi tr k trc ca gi tr thc t: PVn-1 = PVn

t Bias bng gi tru ra: MX = MnBit nhca mt b PID c gi tr mc nh l 1 (ON), c t khi CPU khi ng hay chuyn t chSTOP sang ch RUN. iu cng c ngha l khi b PID c thc hin ln u tin, CPU khngnhn bit s chuyn i trng thi ca dng nng lng t 0 ln 1 v do khng thc hin cc thao tcnu trn.

Lnh PID l mt lnh n gin nhng rt mnh trong vic tnh ton thut ton PID. Nu cn mt s tnhnng khc, v d nh bo ng hay nhng thay i c bit, c th s dng cc lnh khc can thip.Khi chng trnh s dng c bin dch, li bin dch c th xut hin nu a ch bng tham s [TBL]hoc ton hng [LOOP] ca b PID vt ra ngoi phm vi cho php (out of range).Mt s phm vi cho php khng c kim tra, v vy ngi lp trnh phi ch . Chng hn nh nhng gitr yu cu v thc t phi l cc s thc nm trong khong t 0.0 n 1.0, cng nh cc gi tr thc t ktrc hay Bias, nu c s dng, khng c vt ra ngoi khong [0.0 - 1.0].Nu li xut hin trong qu trnh tnh ton thut ton PID, bit c bit SM1.1 (overflow) s bng 1 v qutrnh tnh ton b dng li. Trong nhng trng hp nh vy, u ra ca b PID c th cha c hon


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thnh, v vy ngi lp trnh phi ch kim tra bit c bit ny s dng u ra mt cch hp l cngnhiu chnh cc du vo nu cn thit.nh dng bng cc tham s ca mt b PID bao gm 36 bytes nh sau:

Mt v d dng biu khin PID:

Mt b nc c dng gi mt p lc ct nc cnh. Nc chy ra khi b vi tc thay ikhng xc nh. t mc ch ngi ta s dng mt bm nc c lu lng iu chnh c mt cchlin tc bm nc vo b.

Gi tr yu cu trong v d ny l phi gi mc nc trong b75%. Gi tr thc t chnh l mc nc oc, thay i t 0% (khi b cn) n 100% (khi by). Gi tr x l (u ra biu khin PID) l vn tcbm, iu chnh c t 0% n 100% lu lng danh nh.

Gi tr yu cu, khng thay i, sc ghi trc tip vo bng cc tham s ca b PID. Gi tr thc t l gitr khng i du (ch dng - unipolar) v l gi tr tng tc vo t bo mc. Gi tru ra PID cngl gi tr tng t, unipolar, dng diu khin tc bm. C hai gi tr tng t ny, i vi S7-200,nm trong khong t 0 n 32000.

Ta s dng biu khin PI (ch bao gm thnh phn t l v tch phn, khng cha thnh phn vi phn).Cc hng siu khin c tnh ton da trn nhng thng s k thut ca hiu khin v c thiuchnh trong qu trnh khai thc thc t. y ta khng i su vo vn ny.

Kc = 0.25Ts = 0.1 s

Ti = 30 minBm c iu khin bng tay cho n khi mc nc trong bt 75% th chuyn sang ch tng vmvan cho nc chy ra khi b. u vo I0.0 c s dng i ch: I0.0 = 0 l Manual; I0.0 = 1 lAuto. Khi trong ch Manual, tc bm c xc nh bi s thc trong khong [0.0 - 1.0] ghi

VD10

Chng trnh:


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10. Lnh php ton logic

10.1 Lnh o byte, word, doubleword

10.2 Lnh AND, OR, XOR


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AND bytes, OR bytes, EXCLUSIVE OR bytes: Lnh AND Bytes thchin php ton l gic AND gia cc bit tng ng ca cc byte u voc nh a ch bi cc u vo IN1 v IN2, kt qu lu vo byte cnh a ch bi u ra OUT. Lnh OR Bytes thc hin php ton l gicOR gia cc bit tng ng ca cc byte u vo c nh a ch bicc u vo IN1 v IN2, kt qu lu vo byte c nh a ch bi ura OUT. Lnh EXCLUSIVE OR Bytes thc hin php ton l gic XORgia cc bit tng ng ca cc byte u vo c nh a ch bi ccu vo IN1 v IN2, kt qu lu vo byte c nh a ch bi u raOUT.

Nhng li c thc gy nn bi lnh ny (ENO = 0):+ Bitc bit SM4.3 = 1: li Run - Time.+ Li 0006: a chgin tip.Nhng bit nhc bit c ni dung bnh hng bi lnh ny:+ SM1.0 (Zero): bng 1 nu kt qu bng 0.

Tng tcho cc cu lnh AND words, OR words, EXCLUSIVE OR words. AND double words, OR doublewords, EXCLUSIVE OR double words.

V d cc lnh l gic:

11. Lnh dch v quay

11.1 Dch tri hay phi

Nhng lnh ghi dch (shift) ni dung mt byte c nh a ch biu vo IN i [N] ln (nh bi ton hng N), mi ln mt bit sang phi(Shift Right Byte) hoc sang tri (Shift Left Byte), kt qu lu vo bytec nh a ch bi u ra OUT. Php ghi dch (shift) in gi tr 0(OFF) vo cc bit b dch i. Nh vy nu s ln dch [N] ln hn 8,thc t ch cn dch ti a 8 ln v sau kt qu chc chn bng 0.

Nu s ln dch [N] ln hn 0, bit cui cng trong byte b dch ra ngois c ghi vo bit c bit SM1.1 (overflow). Bit c bit SM1.0(zero) s c gi tr 1 (ON) nu kt qu cui cng sau php dch bng 0.Cc lnh ghi dch mt byte u xem cc byte l nhng s khng du (unsigned).


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Nhng li c thc gy nn bi lnh ny (ENO = 0):+ Bitc bit SM4.3 = 1: li Run - Time.+ Li 0006: a chgin tip.Nhng bit nhc bit c ni dung bnh hng bi lnh ny:+ SM1.0 (Zero): bng 1 nu kt qu bng 0.+ SM1.1 (Overflow): bng bit cui cng b dch ra ngoi.

11.2 Quay tri hay phi

Nhng lnh quay (rotate) ni dung mt byte c nh a ch bi u vo IN i [N] ln (nh bi tonhng N), mi ln mt bit sang phi (Rotate Right Byte) hoc sang tri (Rotate Left Byte), kt qu lu vobyte c nh a ch bi u ra OUT. Php quay (rotate) in gi tr bit cui cng (b quay ra ngoi) vobit u tin. Nh vy nu s ln quay [N] ln hn 8, thc t ch cn quay mt s ln bng s d trong phpchia [N] cho 8 v sau qu trnh sc lp li. Do s ln quay thc t ch nm trong khong t 0 n7. Nu s ln quay bng 0 (hay s ln quay chia ht cho 8), php quay khng c thc hin. Trong trnghp php quay c thc hin, bit cui cng trong byte b quay ra ngoi sc ghi vo bit c bit SM1.1(overflow). Bit c bit SM1.0 (zero) s c gi tr 1 (ON) nu kt qu cui cng sau php quay bng 0.Cc lnh ghi quay mt byte u xem cc byte l nhng s khng du (unsigned).

Nhng li c thc gy nn bi lnh ny (ENO = 0):+ Bitc bit SM4.3 = 1: li Run - Time.+ Li 0006: a chgin tip.

Nhng bit nhc bit c ni dung bnh hng bi lnh ny:+ SM1.0 (Zero): bng 1 nu kt qu bng 0.+ SM1.1 (Overflow): bng bit cui cng b quay ra ngoi.

V d s dng cc php dch v quay:


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11.3 Lnh dch thanh ghi cc bit (Shift Register Bit):

Lnh ny dch (shift) ni dung mt khi cc bit lin tip i mt bit, vibit u tin b dch i c thay th bng gi tr bit c trn bi tonhng DATA v bit cui cng b dch ra ngoi sc ghi vo bit c bitSM1.1. Khi cc bit lin tip ny c xc nh vi bit u tin (bit thpnht) c a chnh bi ton hng S_BIT v c di bng gi tr tuyti ca ton hng [N]. iu c ngha [N] l mt s c du, du ca[N] xc nh chiu dch chuyn: [N] dng th dch ln cn [N] m thdch xung.Nhng li c thc gy nn bi lnh ny (ENO = 0):

+ Bitc bit SM4.3 = 1: li Run - Time.+ Li 0006: a chgin tip.+ Li 0091: ton hng vt qu gii hn cho php.+ Li 0092: li trng s(count field).Nhng bit nhc bit c ni dung bnh hng bi lnh ny:+ SM1.1 (Overflow): bng bit cui cng b quay ra ngoi.

Minh ha lnh ny vi khi cc bit bt u t V33.4 v c di 14 bit:

V d khc:


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11.4 Lnh SWAP

Lnh ny (Swap Bytes) c ton hng l mt tn (Word) c nh ach bi u vo IN. Lnh Swap tro i ni dung hai byte nhca mt tn: byte cao thnh byte thp v byte thp thnh byte cao. Kt qucghi vo chnh tn l ton hng ca lnh.Nhng li c thc gy nn bi lnh ny (ENO = 0):+ Bitc bit SM4.3 = 1: li Run - Time.+ Li 0006: a chgin tip.

V d v lnh dch chuyn v lnh Swap:

12. Cc lnh iu khin chng trnh

12.1 END c iu kin

Lnh END c iu kin dng kt thc chng trnh chnh khi thamn iu kin trc n.Lnh END khng c ton hng, khng c s dng trong cc chngtrnh con hay trong cc chng trnh x l ngt. Phn mm STEP 7Micro / Win 32 t ng thm lnh END khng iu kin (lnh ENDkhng c bt c iu kin no trc n) vo cui mi chng trnhchnh.

12.2 STOP

Lnh STOP dng chng trnh ang c thc hin ngay lp tc bngcch chuyn CPU t ch hot ng (RUN) sang ch STOP. Nu lnh STOP c thc hin t mtchng trnh x l ngt th chng trnh x l ngt y s b kt thc ngay ng thi tt c nhng ngt angchc x l (nu c) cng u b hy. Tuy nhin CPU vn x l nt nhng lnh cn li trong vng qut


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ca chng trnh chnh khi b ngt v ch dng chng trnh cui vng qut bng cch chuyn ch tRUN sang STOP.

12.3 Lnh Watchdog Reset

Lnh ny khi ng li ng h canh h thng (System Watchdog). iu cho php ko di thi gianthc hin vng qut m khng b li watchdog. Ch cn thn khi s dng lnh ny v khi n nm trongcc vng lp (khng kt thc vng qut) hay khi n ko di vng qut snh hng ti h thng, chng hnnh vic thc thi cc tnh nng: Truyn thng (tr ch FreePort) Cp nht cc u vo ra (tr nhng lnh truy xut trc tip) Cp nht Forcing Cp nht cc bit c bit, nh SM0, SM5 n SM29 Chn on li Run-Time Cc bnh thi c phn gii 10 ms v 100ms hot ng sai lch (c bit khi thi gian vng qut vt qu 25s) Lnh STOP c s dng trong chng trnh con x l ngt

Nu mong mun thi gian vng qut qu 500ms, hoc mong l c th chngt qu 300ms th phi dnglnh WDR.

Vic chuyn cng tc ca CPU sang v tr STOP s dng chng trnh trong vng 1.4 giy.

12.4 Lnh nhy

Lnh nhy (Jump to Label) r nhnh chng trnh n mt on lnhc nh du bng mt nhn. Khi mt lnh nhy c thc hin, nhngn xp lun lun c gi tr 1. Nhn dng nh du v tr cho cclnh nhy.C hai lnh trn c ton hng l mt s nguyn trong khong t 0 n255 (s nhn). i vi CPU 212 chc t 0 n 63. Lnh nhy chc php r nhnh chng trnh n mt nhn hoc cng trongchng trnh chnh, hoc cng trong mt chng trnh con hay chng

trnh x l ngt.


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12.5 Lnh SCR

V d:


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Xem thm: iu khin hi t, phn tn, c iu kin, Lnh vng lp For-Next.

13. Lnh chng trnh conLnh gi (CALL) mt chng trnh con chuyn quyn iu khin ncho chng trnh con . S7-200 c th gi mt chng trnh con choc khng c tham s. Trong STEP 7 Micro / Win 32, ta thm chngtrnh con vo chng trnh t Menu chnh Edit > Insert >Subroutine.Lnh kt thc chng trnh con (Return) c iu kin kt thc vic thc

hin chng trnh con v trv chng trnh chnh khi tha mn iukin trc n.Mt khi vic thc hin mt chng trnh con kt thc, quyn iu khin

c chuyn v cho lnh k tip lnh gi chng trnh con y.Ton hng ca lnh gi chng trnh con chnh l nh danh ca chng trnh con, l mt s nguyn trongkhong t 0 n 255.

Nhng li c thc gy nn bi lnh ny (ENO = 0):+ Bitc bit SM4.3 = 1: li Run - Time.+ Li 0008: sln gi chng trnh con vt qu con scho php.

STEP 7 Micro / Win 32 tng gn lnh kt thc v tr v t chng trnh con (RET) vo cui michng trnh con c thm vo.

Mt chng trnh con c thc gi t trong mt chng trnh con, hin tng ny gi lNesting. suca Nesting ti a l 08 ln gi. Vic gi n mt chng trnh con t chnh n ( qui - Recursion) khngb cm nhng ngi lp trnh phi tht s cn trng vi cch dng ny.

Khi gi mt chng trnh con, CPU lu li ton b ngn xp, ghi gi tr 1 vo nh ngn xp v 0 vo ccgi tr cn li ca ngn xp ri chuyn quyn iu khin cho chng trnh con. Khi vic thc hin mtchng trnh con hon tt, ngn xp c phc hi li trng thi trc v quyn iu khin c chuyn


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v cho chng trnh gi. Lu nhng thanh ghi a nng (Accumulators) khng c lu hay phc hitrong cc qu trnh trn.

Vic gi mt chng trnh con vi tham sc thc hin thng qua vic nh ngha cho chng trnh conmt bng tham s cc b. Mi tham s bao gm tn tham s (ti a 08 k t), kiu bin (vo, ra hay tmthi) v kiu d liu (Bool, Byte, INT, ...). Mi chng trnh con c th c nhiu nht 16 tham s.

Kiu bin ca tham s xc nh tham s vo cho chng trnh con (IN), va vo va ra (IN_OUT) hay ltham s ra t chng trnh con (OUT). C th nh sau: Tham s dng vo (IN) c truyn n cho chng trnh con: Nu tham s l a ch trc tip (v d

VB10), ni dung nha chy sc truyn vo cho chng trnh con; Nu tham s l a chgin tip (v d *AC1), ni dung nhc trn sc truyn vo cho chng trnh con; Nu thams l hng s (v d 16#9A8B) hay l mt a ch (v d &VB100), hng s hay a chy sctruyn vo cho chng trnh con.

Tham s dng vo - ra (IN_OUT): chng trnh con s dng s liu ta ch xc nh bi tham s nyng thi xut d liu cng ra a chy. Hin nhin rng tham s dng ny khng th l mt hng s(nh 16#1234) hay a ch (nh &VB100).

Tham s dng ra (OUT): chng trnh con xut d liu ra a ch ny. Tham s dng ny khng th lmt hng s (nh 16#1234) hay a ch (nh &VB100).

Tham s cc b (TEMP): l nhng tham sc chng trnh con s dng ch trong phm vi chngtrnh con ny.Local variable tabble:

thm vo mt tham s cho mt chng trnh con, trong bng cc tham su chng trnh con (hnhpha trn) t con tr vo kiu bin ta mun thm (IN, IN/OUT, OUT hay TEMP), nhn phm phi chut vchn Insert > Rowbelow thm vo mt tham s mi v tr di con tr vi dng tham s thch hp.

Kiu d liu ca tham s xc nh kch thc cng nhnh dng ca n: Kiu dng nng lng (Boolean Power Flow): c xem l kiu bit l gic nhng ch c th l dng vo

(IN) v phi c khai bo trc tt c cc kiu khc (nh nhng tham s EN v IN1 trong v d trn). Kiu bit l gic (Boolean): i din cho mt bit, c th l dng ra (OUT) hoc vo (IN), nh IN3. Kiu Byte, Word, DWord: tham s ra hoc vo, 1, 2 hay 4 bytes i din cho cc s khng du Kiu Int, DInt: tham s ra hoc vo, 2 hay 4 bytes i din cho cc s nguyn c du (signed). Kiu Real: tham s ra hoc vo, i din cho cc s thc du phy ng 4 bytes (theo chun IEEE).

Mt v d gi chng trnh con vi cc tham sc khai bo nh trn:

Trong v d trn, tham s IN4 = &VB100 c cha vo mt t kp (double word unsigned). Nu gn chotham s mt gi tr l hng s, 16#1234 chng hn th phi xc nh kiu d liu cho n bng cch vitDW#16#1234.


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Tp lnh S7-200Khi mt chng trnh con c gi, n bao gm mt vng d liu cc b cha cc tham s (c nh ach nh ct u tin ca bng cc tham s). Nhng tham s dng vo sc sao chp vo vng d liu ccb ny trc khi chng trnh con thc hin v nhng tham s dng ra li c sao chp ra t vng y saukhi vic thc hin chng trnh con hon thnh. Lu chng trnh con khng kim tra kiu d liu nnngi lp chng trnh phi ch s dng ng kiu khai bo.Tt nhin th t cc tham s cng phi ph hp nh khai bo (c bit trong STL): u tin l dng vo(IN) ri n cc dng vo - ra (IN/OUT) v dng ra (OUT).

V d s dng chng trnh con:

14. Lnh ngtXem gio trnh l thuyt.

dieu khien logic giao trinh tap lenh - hoi

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