Module PID_F.pdf

8/10/2019 Module PID_F.pdf

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Trng TCN KTCN Hng Vng TT C in T

K.S Trn Vn HiuEmail: [email protected]

161165 Nguyn Ch Thanh, Phng 12, Qun 5

MODULE MM PID

Nhng module mm c trong Step7

Phn mm Step7 cung cp cc module mm PID iu khin cc i tng c mhnh lin tc nh l, ng c,mc u ra ca i tng c a vo u vo ca cc biu khin qua cc cng vo tng t ca cc module vo tng t ca Simantic s7-300/400. Tn hiu ra ca b iu khin c nhiu dng v c a n cc c cu chp hnhqua nhng module vo ra khc nhau nh:

Qua cng ra tng t ca cc module ra tng t (AO) hoc Qua cc cng ra s ca module ra s(DO) hoc Qua cc cng pht xung ra tc cao

Ph thuc vo c cu chp hnh, ngi s dng c th chn module mm PID tngthch . Ba module PID c tch hp trong phn mm Step7 ph hp vi ba kiu c cu

chp hnh nu trn, l:

1.iu khin lin tc vi module mm FB41(tn chnh thc CONT_C)

2.iu khin bc vi module mm FB42(tn chnh thc CONT_S)

3.

iu khin kiu pht xung vi khi hm h tr FB43(tn chnh thcPULSEGEN)

Ch : Khi sdngcc hm ny cnkhai bo trong OB35 ( khiOB ngttheo chu k)Ngoi ra Module mm PID cn h tr thm cho phn v th vi khi hm FB58"TCONT_CP" htrcho hm FB41 v FB59 "TCONT_S"

I. IU KHIN LIN TC VI FB41(CONT_C)

S cu trc ca module mm c minh ha trong hnh :FB41(CON_T) c s ng iu khin cc qu trnh k thut vi cc bin u

vo v u ra tng t trn c s thit b kh trnh Simantic. Trong khi thit lp tham s, cth tch cc hoc khng tch cc mt s thnh phn chc nng ca b iu khin PID saocho ph hp vi i tng.


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Cutrc camodule phnmmFB41 CON_C

C th s dng module mm PID nh mt b iu khin vi tn hiu ch o tcng ( fix setpoint) hoc thit k mt h thng iu khin nhiu mch vng theo kiu iukhin cascade. Nhng chc nng iu khin c thit k trn c s ca lut iu khin PIDca b iu khin mu vi tn hiu tng t.

Module mm PID bao gm tn hiu ch o SP_INT, tn hiu ra ca i tngPV_PER , tn hiu gi m phng tn hiu ra ca i tng PV_IN , cc bin trung giantrong qu trnh thc hin lut v thut iu khin PID nh PVPER_ON,P_SEL,I_SEL ,D_SEL , MAN_ON..

Tn hiu ch o SP_INT c nhp di dng s thc du phy ng.


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Tn hiu ra ca i tng PV_PER:Thng qua hm ni ca FB41 c tn CRP_IN,tn hiu ra ca i tng c th c nhp di dng s nguyn c du hoc s thc duphy ng. Chc nng ca CRP_IN l chuyn i kiu biu din ca PV_PER t dng snguyn sang s thc du phy ng c gi tr nm trong khong -100 n 100% theo cngthc:

Tn hiu ra ca CRP_IN = PV_PER*100/27648Chun ha : chc nng ca hm chun ha PV_NORM tn hiu ra ca i tng l

chun ha tn hiu ra ca hm CRP_IN theo cng thc

Tn hiu ra ca PV_NORM=(tn hiu ra ca CRP_IN) * PV_FAC_OFF

Hai tham tr khng ch gii gi tr cho php ca PV_NORM l PV_FAC vPV_OFF . Mc nh PV_FAC ca hm PV_NORM c gi tr bng 1 v PV_OFF c gi trbng 0.

Lc nhiu tc ng trong ln cn im lm vic. Tn hiu sai lch l hiu gia tnhiu ch o vtn hiu ra ca i tng. N c to ra ngay trong FB41 v l u vo cakhi DEADBAND hoc ca i tng m c th b qua s nh hng ca nhiu trong lncn im lm vic ta chn DEAD_W = 0

Chn lut iu khin trn module FB41 (CONT_C)

Hnh vdim t thut PID c thit k theo kiu song song ca 3 thut iu khin nl : t l P, tch phn I v vi phn D theo s cu trc (sau khi DEADBAND) Chnh vcu trc song song nh vy nn ta c th thng qua cc tham tr P_SEL,I_SEL, hay D_SELm tch hp cc thut iu khin khc nhau t b ly mu nh thut iu khin P , PI , PID

ThutiukhinPID

t gi tr :

Phn mm cho php chn ch t ng ( automatic mode) hoc ch bng tay. ch bng tay cc gi tr ca cc bin c chn bng tay . B tch phn (INT) t thit lp ch


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LNM_LNM, P-DISV v b vi phn (DIF) t ng v 0. iu m bo cho vic chuynch t thit b lp gi tr bng tay v ch t ng khng gy nn 1 bin i t ngtno ivi cc bin c thit lp gi tr bng tay.

Cng c th gii hn cho cc gi tr c thit lp bng tay nh hm LMNLIMIT . Mtbit c s c gi tr logic bng 1 khi bin vo c gi tr vt qa gii hn chn. Hm

LMN_MORM s chun ha tn hiu ra ca hm LMNLIMIT theo cng thc :LMN_PER = LMN *27648/100

Ngai ra nhiu c th c lc trc bng cch a qua u vo DISV

Khi ng v thng bo li :

FB41 (CONT_C) c mt chng trnh con phc v cho vic khi to li tan b hthng. Chng trnh ny c gi khi tn hiu vo COM_RST c gi tr logic bng 1.

Trong khi khi to ,lut iu khin tch phn c t ng thit lp vi gi tr khito I_ITVAL. Nu lut iu khin ny c gi theo ngt thi gian, n s lun lm vic vigi tr ny. Tt c cc u ra khc c t gi tr mc nh .Khi FB41 (CONT_C) khng c kh nng t kim tra li bn trong ca module mm PID .M bo li RET_VAL khng c s dng.

Tham bin chnh thc u vo:Khi FB41(CONT_C) c 26 tham bin chnh thcuvo nhsau:

BinKiudliu

TmGi tr Mc nh M tchcnng

COM_RST BOOL FALSECOMPLETE RESTARTKhi c chc nng khi to li h thnghon tan khi u vocomplete restart

MAN_ON BOOL TRUEMANUAL VALUE ON

Khi u vo manual value on c gi trlogic TRUE mch vng dk s b ngt, ccgi trthit lp bng tay

PVPER_ON BOOL FALSE

PROCESS VARIABLE PERIPHERAL ON

Khi c bin qu trnh t cc cng vo/rau vo PV_PER phi c ni vi cc

cng vo/ra v u vo process variableperipheral c gi tr logic True


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P_SEL BOOL TRUE

PROPORTIONAL ACTION ON

Hot ng ca b dk PID c th tch cchoc khng tch cc tng phn ring trongthut dk PID , thut dk t l c kch hot khigi tr logic True c thit lp ti cng vo

proportional action on

I_SEL BOOL TRUE

INTEGRAL ACTION ON

Hot ng ca b dk PID c th tch cchoc khng tch cc tng phn ring trongthut dk PID , thut dk t l c kch hot khigi tr logic True c thit lp ti cng voproportional action on

INT_HOLD BOOL FALSEINTEGRAL ACTION HOLD

u ra ca b iu khin tch phn c th b

ng lnh (not use) khi thit lp gi tr logictrue cho u vo intergral action hold

I_ITL_ON BOOL FALSE

INITIALIZATION OF THE INTEGRALACTION

u ra ca b k tch phn c th c nivo cng vo I_ITL_VAL nu nh cng voinitialization of the intergral action on cgi tr logic true

D_SEL BOOL FALSE

DERIVATIVE ACTION ON

Hot ng ca b dk PID c th tch cchoc khng tch cc tng phn ring trongthut dk PID. Thut dk vi phn c kchhot khi gi tr logic True c thit lp ticng vo derivativeaction on

CYCLE TIME >= 1ms T#1sSAMPLING TIME

Thi gian ly mu l khong thi giankhng i gia cc ln khi c cp nht.

SP_INT REAL

-100.0...100.0(%) hoc gi

tr vt l

0.0

INTERNAL SETPOINTu vo internalsetpoint c s dng

tht lp tn hiu ch o (tn hiu mu)

PV_IN REAL

-100.0...100.0(%) hoc gi trvt l

0.0

PROCESS VARIABLE IN

Gi tr khi to c th t u voprocessvariable in hoc t bin qu trnhc ni vi CPU thng qua cng votng t


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PV_PER WORDW#16#0000 PROCESS VARIABLE PERIPHERAL

Bin qu trnh c ni vi CPU qua cngvo tng t

MAN

REAL

-100.0...100.0

(%) hoc gitr vt l0.0

MANUAL VALUE

Cng vo manualvalue c s dng tgi tr bng cc hm giao din

GAIN REAL 2.0 PROPORTIONAL GAIN

u vo proportional gain c s dng thit lp h s t l cho b iu khin theolut t l

TI TIME >= CYCLE T#20sRESET TIME

Cng vo reset time c s dng thit lp hng s thi gian tch phn chob dk tch phn

TD TIME >= CYCLE T#10sDERIVATIVE TIME

Cng vo derivate time c s dng thit lp hng s thi gian vi phn cho b dkvi phn

TM_LAG TIME >= CYCLE/2 T#2sTIME LAG OF THE DERIVATIVE

ACTION

Thi gian tch cc ca lut iu khin viphn c chon thng qua cng vo time lag of the derivate action

DEADB_W REAL>=

0 (%) hocgi tr vtl

0.0DEAD BAND WIDTH

Mt vng km nhy x l tn hiu sailch. rng ca vng km nhy c tthng qua cng vo deadband width

LMN_HLM REAL

LMN_LIM

0 (%) hocgi tr vtl

100.0

MANIPULATED VALUE HIGH LIMIT

Gii hn ch trn c tht lp bng tayqua cng vo manipulated value highlimit

LMN_LLM REAL

-100

LMN_LIM(%) hocgi tr vt

0.0

MANIPULATED VALUE LOW LIMIT

Gi tr hn ch di c thit lp bng taythng qua cng vo manipulated valuelow limit


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PV_FAC REAL 1.0PROCESS VARIABLE FACTOR

Bin qu trnh c nhn vi mt h s choph hp vi phm vi qui nh ca bin ny.H s c chn thng qua cng voprocessvariable factor

PV_OFF REAL 0.0PROCESS VARIABLE OFFSET

Bin qu trnh c cng vi mt lng bcho ph hp vi phm vi qui nh ca binny . Gi tr b c chn thng qua cngvo processvariable offset

LMN_FAC REAL 1.0

MANIPULATED VALUE FACTOR

Gi tr gii hn c nhn vi mt h scho ph hp vi phm vi qui nh ca binqu trnh. H s ny c t qua cng vo

manipulatedvalue factor

LMN_OFF REAL 0.0MANIPULATED VALUE OFFSET

Gi tr gii hn c cng thm mt lngb cho ph hp vi phm vi qui nh cabin qu trnh. H s ny c t quacng vo manipulatedvalue offset

I_ITLVALREAL

-100.0...100.0(%) hoc gitr vt l

0.0

INITIALIZATION VALUE OF THE

INTEGRAL ACTION

Gi tr u ra ca b iu khin tch phn cc thit lp thng qua cng vo

initializationvalue of the integral action.

DISV REAL

-100.0...100.0(%) hoc gitr vt l

0.0DISTURBANCE VARIABLE

Khi iu khin h thng bng phng phpfeedforward th mt gi tr b nhiu ct thng qua cng vo disturbancevariable.

Tham bin chnh thc u ra:Khi FB41 (CONT_C) c 9 tham bin chnh thc u ranh sau:

Bin Kiu dliu

Tm Gi tr Mc nh M t

LMN REAL 0.0 MANIPULATED VALUE

Gi tr c thit lp bng tay thng quacng manipulatedvalue


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LMN_PER WORD W#16#0000 MANIPULATED VALUE PERIPHERAL

Gi tr u ra thit lp bng tay theo kiubiu din ph hp vi cc cng vo/ratng t c chn qua cng ra the manipulatedvalueperipheral

QLMN_HLM BOOL FALSE HIGH LIMIT OF MANIPULATEDVALUE REACHED

Cng ra highlimit of manipulated valuereached thng bo gi tr bin qu trnhvt qu gi tr gii hn trn

QLMN_LLM BOOL FALSE LOW LIMIT OF MANIPULATED

VALUE REACHED

Cng ra low limit of manipulated valuereached thng bo gi tr ca bin qutrnh nh hn gi tr gii hn di

LMN_P REAL 0.0 PROPORTIONAL COMPONENT

Tn hiu ra ca b k t l c xutqua cng ra proportionalcomponent

LMN_I REAL 0.0 INTEGRAL COMPONENT

Tn hiu ra ca b k tch phn c xut qua cng ra intergralcomponent

LMN_D REAL 0.0 DERIVATIVE COMPONENT

Tn hiu ra ca b k vi phn c xutqua cng ra derivativecomponent

PV REAL 0.0 PROCESS VARIABLE

Tn hiu qu trnh c xut qua cng ra theprocess variable

ER REAL 0.0 ERROR SIGNAL

Tn hiu sai lch c xut qua cng ra error signal

I I .IU KHIN BC VI FB42 CONT_S

FB42 CONT_S c s dng trn c s Simantic s7 300/400 iu khin cc itng k thut vi u ra ca b iu khin l tn hiu s. Tn hiu ra s hon tan thch hpvi cc c cu chp hnh kiu tch phn. Trong khi thit lp tham s, ngi thit k c thtch cc hoc khng tch cc b k PI bc cho ph hp vi yu cu ca bi ton k t ra.C th s dng module mm FB42 CONT_S nhmt b k theo lut PI vi tn hiu ch


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o t trc hoc c th s dng n trong mch vng k ph trong h thng thit k datrn nguyn tc k cascade. Chc nng ca b k ph trong h thng thit k da trnnguyn tc k cascade. Chc nng ca b kny hon tan tun theo thut k PI vi tnhiu qu trnh l tn hiu tng t v tn hiu ra ca b k l tn hiu s.

Mt phn trong cc chc nng ca module mm ny l ng vai tr ca mt b k PI

c cc gi tr tn hiu u ra s t bng tay. Lm vic ch ny l b k bc khngcn n tn hiu hi tip .

Hnh sau m t hot ng ca FB42 CONT_S

Scu trc nguyn l camodule mmFB42 CONT_S


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Tn hiu ch o : c biu din s thc du phy ng v c thit lp t cng vo SP_INT

Tn hiu ra ca i tng : c a thng t cng vo tng t theo kiu s nguyn

hoc c truyn sau khi bin i sang kiu s thc du phy ng. HmCRP_IN c chc nng bin i gi tr truyn t cng vo tng t sang kiu s thcdu phy ng trong khong t -100% n 100% theo cng thc

Tn hiu ra ca CRP_IN = PV_PER * 100/27648

Chun ha : chc nng ca hm PV_NORM l chun ha tn hiu ly t u ra cahm CRP_IN theo cng thc

Tn hiu ra ca PV_NORM = ( tn hiu raca CRP_IN) * PV_FAC + PV_OFF .

Mc nh PV_FAC c gi tr bng 1 v PV_OFF c gi tr bng 0 .

Lc nhiu tc ng trong ln cn im lm vic: tn hiu sai lch l hiu gia tnhiu ch o v tn hiu ra ca i tng. Ging nh FB41 , trong FB42 cng c khiDEADBAND c thit k ngay sau tn hiu sai lch v trc phn iu khin theo lut lc nhng dao ng nh quanh gi tr xc lp bng cch to ra mt vng km nhy .Nu gi tr DEADB_W=0 th vng km nhy khng tn ti.

THUT IU KHIN PI BC

Khi hm FB42 ca module mm PID lm vic khng cn phi c tn hiu hi tip.Chc nng ca lut I trong thut k PI v tn hiu sai lch c tnh trong mt b tch phn

INT, sau so snh vi tn hiu ra ca b k theo lut t l nh mt gi tr hi tip. Hiu caphp so snh ny c a vo mt r le ba v tr c tr Three_ST v u ra ca r le nyk b pht xung ra PULSEOUT k c cu chp hnh . C th gim tn s ng ct cab k bng cch to ra vng tr khi chuyn v tr ca r le.

Ngai ra gim nh hng ca nhiu trong trng hp k khng hi tip, c thlc nhiu cho h bng cch a tn hiu vo u vo DISV ca b lc nhiu.

KHI NG V THNG BO LI

H thng c khi to li hon tan khi cng vo COM_RSTc gi tr bng 1. Ttc cc cng ra nhn gi tr mc nh. Khi hm FB42 ny khng c kh nng t kim tra

li bn trong. N khng s dng cng ra bo kiu li RET_VAL

Tham bin chnh thc u vo:

Bin Kiu dliu

Tm gi tr Mc inh M t


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COM_RST BOOL FALSE COMPLETE RESTART

Module mm c khi to li hon tan khi cng vo completerestart c gi tr logic

bng 1

LMNR_HS BOOL FALSE HIGH LIMIT OF POSITION FEEDBACKSIGNAL

Tn hiu actuatorat upper limit stopc nin cng vo high limit of position feedback. Cng ra c cu chp hnh s b cm khi .LMNR_HS=TRUE

LMNR_LS BOOL FALSE LOW LIMIT OF POSITION FEEDBACKSIGNAL

Tn hiu actuatorat lower limit stopc nin cng vo low limit of position feedbacksignal . Cngra c cu chp hnh s b cm

khiLMNS_ON BOOL FALSE MANUAL ACTUATING SIGNALS ON

X l tn hiu chp hnh chuyn sang ch bng tay qua cng vo manualactuating signalson

LMNUP BOOL FALSE ACTUATING SIGNALS UP

Tn hiu ra QLMNUPcthit lp qua cng voactuatingsignals up vi cc tn hiu chp hnh

bng tay

LMNDN BOOL FALSE ACTUATING SIGNALS DOWN

Tn hiu ra QLMNDN c thit lp qua cngvo actuating signals down. Vi cc tn hiuchp hnh bng tay

PVPER_ON BOOL FALSE PROCESS VARIABLE PERIPHERAL ON

Mun c cc tn hiu qu trnh t cc cngvo/ra th cng vo process variable

peripheral on phi c gi tr logic 1(chophp c)

CYCLE TIME >= 1ms T#1s SAMPLINGTIME

Khong thi gian gi cc ln gi khi phikhng c nh . Thi gian trch musampling time c thit lp qua cng vosampling time

SP_INT REAL _100.0100.0

(%)

or phys. value

1)

0.0 INTERNAL SETPOINT

Tn hiu ch o c t qua cng vointernalsetpoint


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PV_IN REAL -100.0...100.0

(%) hay

phys.value

1)

0.0 PROCESS VARIABLE IN

PV_PER WORD W#16#0000 PROCESS VARIABLE PERIPHERAL

Bin qu trnh theo kiu biu din s nguync truyn trc tip t cng vo/ra tng tqua cng vo processvariableperipheral

GAIN REAL 2.0 PROPORTIONAL GAIN

H s khuych i ca thut P c a vproportionalgain

TI TIME >= CYCLE T#20s RESET TIME

Hng s thi gian ca lut tch phn I c tqua cng resettime

DEADB_W REAL -100.0...100.0

(%)

or phys. value

1)

1.0 DEAD BAND WIDTH vo deadVng km nhy x l tn hiu sai lch. rng ca vng km nhy c t qua cng

band width

PV_FAC REAL 1.0

PV_OFF REAL 0.0 PROCESS VARIABLE OFFSET

Bin qu trnh c cng vi mt lng bcho ph hp vi phm vi qui nh ca binny. Gi tr b c chn thng qua cng voprocessvariable offset

PULSE_TM TIME >= CYCLE T#3s MINIMUM PULSE TIME

Chu k pht xung nh nht c t quacng vo minimumpulse time

BREAK_T

M

TIME >= CYCLE T#3s MINIMUM BREAK TIME

Thi gian cm nh nht c t quacng vo minimumbreak time

MTR_TM TIME >= CYCLE T#30s MOTOR ACTUATING TIMEKhong thi gian cn thit c cu chp hnhchuyn t gii hn dng ny sng gii hanhdng khc c t qua cng vo motoractuating time


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DISV REAL -100.0..100.0

(%) or phys.

value

2)

0.0 DISTURBANCE VARIABLE

Khi iu khin h thng bng phngphp feedforward th mt gi tr b nhiuc t thng qua cng vodisturbancevariable.

Tham bin chnh thc u ra:

Bin Kiu dliu

Tmhat ng Mcnh M t

QLMNUP BOOL FALSE ACTUATING SIGNAL UP

C cu chp hnh van c m khi cng raactuatingsignal up c set

QLMNDN BOOL FALSE ACTUATING SIGNAL DOWN

C cu chp hnh van c ng khicng ra actuatingsignal down set

PV REAL 0.0 PROCESS VARIABLE

Bin qu trnh c th c xut quacng process variable

ER REAL 0.0 ERROR SIGNAL

Tn hiu sai lch c th c xut qua cngerrorsignal

III. KHI TO HM XUNG FB43 PULSEGEN

1.Gii thiu FB43Khi hm FB43 c s dng to mt b iu khin PIDvi xung u ra cho c cu

chp hnh kiu t l.2.ng dng ca FB43

FB43 c tc dng h tr vic thit k mt b iu khin PID 2 hay 3 v tr vi b to xungtheo nguyn tc iu bin3.M t FB43

FB43 thng c s dng vi FB41 to ra mt biu khin vi u ra tn hiu dngxung.N bin i bin vo INV dng s thc (thng l u ra LMN ca module mmPID) thnh mt dy xung vi chu k c nh tng ng vi chu k thi gian m bin voc update v gi tr chu k ny cn c gn ti PER_TM. rng xung ca mi chu k t l vi bin u vo.Chu k gn cho PER_PM khng c

ng nht vi chu k c gi ca FBPULSEGEN.Khong thi gian PER_TM c tothnh bng vi chu k FB43,nh s ln FB43 c gi mi chu k PER_TM l thc o chnh xc ca khong thi gian iu ch xung.


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Mt gi tr u vo INV=30 tcbng 30% v 10 FB PULSEGEN gi mi PER_PMngha l:1 cng ra QPOS cho 3 ln gi u ca FB43(30% ca 10) 0 cng ra QPOS cho 7 ln gi sau ca FB43(70% ca 10)

S ca FB43 PULSEGEN

a. chnh xc ca bin thao tc(Accuracy of the Manipulated Value):Vi t l ly mu l 1:10(CONT_C gi PULSEGEN) chnh xc ca gi tr bin thao tc

v d trn b hn ch ti 10% .Trong cc trng hp khc s thit lp gi tr u vo INVch c th c m phng bng rng xung cng ra QPOS trong nhng bc bng 10%.

chnh xc s tng ln nu s ln FB43 c gi mi ln FB41 c gi tng ln.NuFB43 c gi,v d hn 100 ln so vi CONT_C,th chnh xc ca gi tr bin thao tcs l 1%.Ch :Tn s gi cn phi c lp trnh bi ngi s dngb. S ng b ha t ng (Automatic Sychronization)

Ta c kh nng ng b ha xung u ra vi khi m update bin u vo INV (vi dCONT_C).iu ny m bo mt s thay i bin u vo s to ra mt s thay i nhanhnht xung u ra .

My pht xung nh ra gi tr u ra INV ti khong dng tng ng ti khong thi gianPER_TM v chuyn i gi tr thnh tn hiu xung vi chiu di tng ng .


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Tuy nhin,INV thng c tnh ton trong mt lp chu k ngt chm hn.Khi to xungln bt u s chuyn i gi tr ri rc thnh mt tn hiu xung cng sm cng tt sau khiINV c update.

cho php iu ny,khi cn ng b ha thi im bt u,s dng cc th tc sau: Nu INV thay i v nu nh khi c gi khng phi l ln u tin hay hai ln gi cui

trong ton chu k, s ng b s c tin hnh. rng xung c tnh ton li v chu kk tip l u ra vi chu k mi.

Qu trnh t ng b ha c th khng c dng nu SYN_ON c thit lp gi trFALSECh :Vi bt u ca mt chu k mi,gi tr c ca INV c m phng chnh xc trongtn hiu xung nhiu hn hay t hn ty theo s ng b .c.Ch hot ng

Ty thuc vo tham s gn cho my pht xung,b iu khin PID vi three step controlra hay vi mt lng cc (bipolar) hay n cc (monopolar)-2 trng thi c th c nhhnh.

Bng sau minh ha nhng s kt hp cc cng tc chuyn mch ng vi cc ch khcnhau.


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Bng 1.1. Kt hp cng tc chuyn mch

Ch Three Step Controll(iu khin 3 v tr): ch three step control tn hiu chp hnh c th thng qua 3 trng thi.Gi tr nhphn ca tn hiu u ra QPOS_P v QNEG_P c gn cho statuses (tnh trng) ca c cu

chp hnh.Bng sau cho thy mt v d v iu khin nhit

Bng 1.2.V d v iu khin nhit Da trn bin u ra,mt ng biu c tnh c s dng tnh rng

xung.Dng ca biu c xc nh bng rng xung nh nht hay gi tr nh nht cathi gian cm v tha s t l.Gi tr thng thng ca tha s ny l 1.Ch ngot gp trn

biu gy ra bi rng xung nh nht hoc thi gian cm nh nht.

Minimum Pulse or Minimum Break TimeNu tagn ng rng xung nh nht hoc khong thi gian cm nh nht P_B_TM ta

c th ngn chn s ln bt/tt thiu qua gim i sng lm vic ca nhng s chuyni c bn ca c cu chp hnh.Ch :Gi tr tuyt i nh ti bin u vo LMN c thpht ra xung c rng ngn hnP_B_TM v b chn.Gi tr ln pht ra xung c rng di hn (PER_M -P_B_TM) s cthit lp l 100% hay -100%

rng xung dng hay m c tnh ton bng nhn gi tr u vo ( dng %) vikhong PER_TM


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Hnh trn l biu c tnh i xng ca Three Step Controller (tha s t l bng 1)iu khin 3 v tr khng i xng :

Ta s dng tha s t l RATIOFAC,t l gia rng xung dng v m c th cthay i .V d trong qu trnh nhit iu ny cho php s sai khc gia hng s thi gian h

thng c nh cho qu trnh lm nng hay lm mt Tha s t l cng nh hng n rng xung nh nht hay thi gian cm Mt tha s t l 1 rng xung u ra xung dng c tnh t bin u vo bi PER_TM c gim ibng h s t l ratio factor theo cng thc

Ch Two Step control(iu khin 2 v tr):


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Trong ch two_step control,ch c xung dng u ra QPOS_P ca PULSEGEN lc ni iu chnh trng thi bt/tt ca c cu chp hnh.Ph thuc vo khong gi trca bin thao tc ang c s dng,b iu khin 2 v tr c mt khong gi tr bin thaotc 2 cc(bipolar) hay mt cc (monopolar)

Nu gi tr u vo di dng % to ra xung c rng ln hn PER_TM -P_B_TM th ngvi cc gi tr u vo trong khong x2% 100% rng xung c gn l PER_TM v tac Continous On(lin tc m)Nu gi tr u vo di dng % to ra xung c rng nh hn P_B_TM th ng vi ccgi tr u vo trong khong -100% -x1% rng xung c gn l 0 v ta c ContinousOFF(lin tc ng)

Tn hiu u ra ph nh c th tm c ti cng QNEG_P nu nh s kt ni ca biu khin 2 v tr trong vng iu khin yu cu mt tn hiu nh phn o ngc hp logiccho s vn hnh xung.

Ch bng tay trong iu khin 2/3 v tr


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Trong ch vn hnh bng tay (MAN_ON =TRUE),u ra nh phn ca iu khin 2 hay3 v tr c th c thit lp s dng tn hiu POS_P_ON v NEG_P_ON bt chp tn hiuINV

Bng 1.3.Ch iu khin 2 v 3 v tr trong manual modeComplete restart/RestartTrong sut qu trnh khi ng li hon ton,ton b tn hiu ra c gn gi tr bng 0 Bo li trong FB43

Gingnh FB41.Khi ny khng c kh nng t kim tra li.Tham s u ra RET_VALkhng c s dng

S KHI VTHAM SCA FB43PULSEGE

N

Tham bin

hnh thcu vo

Tham s Kiu dliu

Khong gi tr Mc nh M t

INV REAL -100.0..100% 0.0 Mt ga tr bin thao tc dngtng t c ni ti tham sINPUT VARIABLE

PER_TM TIME CYCLE20 T#1s Mt khong thi gian iu ch rng xung c nh l utham s u vo vi PERIODTIME.N tng ng vi thigian ly mu ca b iukhin.T l gia thi gian lymu ca my pht xung v biu khin xc nh chnh xc


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ca s iu ch xung.P_B_TM TIME CYCLE T#50ms Mt gi tr thi gian xung nh

nht hoc thi gian cm nh nhc th gn ti cng P_B_TM ny

RATIOFC REAL 0.110 1.0 Tham s u vo RATIOFC c

th s dng thay i t l gia rng xung m hay dngTrong qu trnh nhit iu nycho php s sai khc hng sthi gian ca qu trnh lm nnghay lm mt.

STEP3_ON BOOL TRUE Tham s u vo three stepcontrol on kch hot ch ny.Trong ch three stepcontrol c 2 tn hiu u rac tch cc

ST2BI_ON BOOL FALSE Vi tham s vo two stepcontrol for bipolar manilulatedvalue range on ta c th chngia 2 ch two step control for bipolarmanilulated value range v twostep control for monpolarmanilulated value range Tham s STEP3_ON cn cgn gi tr FALSE

MAN_ON BOOL FALSE Bng cch thit lp tham s

manual mode on tham s ura c th thit lp bng tay.POS_P_ON BOOL FALSE ch bng tay vi three step

control,tn hiu u ra QPOS_Pc th c thit lp ti tham su vo positive pulse onTrong ch lm vic bng tayvi two step control QNEG_Plun lun c thit lp tringc vi QPOS_P

NEG_P_ON BOOL FALSE ch bng tay vi three step

control,tn hiu u ra QPOS_Pc th c thit lp ti tham su vo negative pulse onTrong ch lm vic bng tayvi two step control QNEG_Plun lun c thit lp tringc vi QPOS_P

SYN_ON BOOL TRUE B ng vic thi t lp u vo


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Sychronization onta s thitlp c ch ng b ha tng vi khi m UPDATE binu vo INV.iu nu bo mrng mt s thay i bin vo s

dn n dn n mt s thay icng nhanh cng tt uradng xung.

COM_RT BOOL FALSE Khi s c khi to li honton nu nu complete restartc thit lp

CYCLE TIME >=1ms T#10ms Khong thi gian gia cc l ngi khi cn l hng s.Tham sSAMPLING TIME xc nhr hng s

Ch :Gi tr ca tham s vo khng b gii hn bn trong khi.Khng c

tham s kim tra Tham bin u ra

Tham s Kiu d liu Khong gi tr Mc nh M tQPOS_P BOOL FALSE Tham s u ra output

positive pulse cthit lp khi m mtxung l u ra.Trongch three stepcontrol N lun lun lxung dng Trong ch

two step controlQNEG_P lun lunc thit lp ngcvi QPOS_P

QNEG_P BOOL FALSE Tham s u ra outputnegative pulse cthit lp khi m mtxung l u ra.Trongch three stepcontrol N lun lun lxung m.Trong ch

two step controlQNEG_P lun lunc thit lp ngcvi QPOS_P


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IV. FB58 TCONT_CP - "PID Temperature Control"

FB58 c dng iukhinnhit caqu trnh lin tchay tn hiuxung iu khin.C thkhai bo cho php hay khng cho php biukhinPID. Nhngthng sc thc khai bo theo htrc sntrong S7-300 theo cch Start > Simatic > Documentation> English > PID Temperature Control.

imt( Setpoint): Setpoint ca vo SP_INT theo kiusthcduchmng(sthcreal)Lachnchhotng(PV_PER ON):

True: cgi tr tcc thitbI/O (PIWxxx) avo PV_PERFalse: cgi trtheo gi trtc a vo PV_IN

Chuynigi trtheo nhdng CRP_IN (PER_MODE):Hm CRP_IN chuyni cc gi trngoivi PV_PER sang sthcdavochchuyncaPER_MODE

PER_MODE Ng ra caCRP_IN Tn hiuAnalog tvo n v0 PV_PER*0.1 Thermoelements; PT100/NI100;

standard

C; F


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1 PV_PER*0.01 PT100/NI100; kh hu C; F2 PV_PER*100/27648 Voltage/Current %

Qu trnh bnh thngha gi tr PV_NORM (PF_FAC, PV_OFFS) :Hm PV_NORM tnh tan ng ra caCRP_IN theo cng thcsau:

Ng ra caPV_NORM = Ng ra caCRP_IN * PF_FAC + PV_OFFSTrong : PF_FAC l hs, PV_OFFS l gi troffset ctnh theo cng thcsau y:

PV_FAC = TmoPV_NORM / Tmo CRP_INPV_OFFS = LL(PV_NORM)PV_FAC*LL(CRP_IN) (LL: gi trcndi)

Gi trmcinh caPV_FAC =1 v PV_OFFS =0. Ng ra caqu trnh sl PV.

Vng cht(DEADB_ W): Vng chtsbttkhi DEADB_W =0.0, licpht sinh bi tham sER

Gii thutPID:

NutTI=0.0 v TD=0.0 th chc iukhin thunP

LMN_Sum(t) : BincabiukhinER(0) : Bcchuynicc bnh thngha sai sGAIN : liTD : Thigian tch phn

TI : Thigian ohmD_F : Hstch phn


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ohm (TI, I_ITL_ON, I_ITLVAL):

Trong chbngtay LMN_I = LMNLMN_PDISV. Nugi trvtqu giihnth ngngohm, nusai sgim v nmtrong vng cho php th licho ohm tip.

Qu trnh ohm sngng khi khai bo TI=0.0Hm tlP syui khi setpoint bi thay i(PFAC_SP)

ngn vtl, c thgim khu tlP bng cch sdngcch thay itlgi trtvo. SdngPFAC_SP c thquytnhhiuqa caP khi setpointthay i:PFAC_SP =1.0 : snhhngkhi setpoint thay iPFAC_SP = 0.0: khng thay ikhi setpoint thay i

Ta c th b hot ng ca P bng hot ng ca I

Tch phn (TD. D_F)- Tch phn sbtt khi TD=0.0

-

Tch phn shotngtheo cng thc: TD =0.5*Cycle*D_FTham scabiukhinP & PD tiimlm vc

- Nukhng sdngohm th cho TI=0.0 v cngnhvitch phn TD=0.0.Khai bo theo thng ssau:

I_ITL_ON = TRUE

I_ITLVAL = imlm vic

Tnh ton cc binckhai bo:


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Vng iukhin( control zone (CONZ_ON, CON_ZONE))

NuCONZ_ON =TRUE th lutiukhinhotngtrong vng iukhin

NuPV > SP_INT trong vng CON_ZONE, gi trLMN_LLM l ng ra caccbinthao tc (iukhinvng kn)

NuPV < SP_INT trong vng CON_ZONE, gi trLMN_HLM l ng ra caccbinthao tc (iukhinvng kn)

NuPV nmtrong vng CON_ZONE, cc binthao tc clytheo lutiukhinPID

Cc binbnh thng ha(Manipulated Variable NormalizationLMN_NORM (LMN_FAC, LMN_OFFS))

LMN = LmnN * LMN_FAC + LMN_OFFS

LMN_PER = LMN * 27648/100

Lugilicc thng s(Saving and Reloading Controller Parameters)


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K.S Trn Vn Hiu

Blu githng s:

Nucc thng squ trnh cthitlpcho php xdng, ta c thlu gin litrckhi n bthay i. Nuiuchnhbiukhin, viclucc thng scscghi trckhi qu trnh hiuchnhxyra.

PFAC_SP, GAIN, TI, TD, D_F, CONZ_ON v CONZONE sclutrong

PAR_SAVE.

Ticc thng siukhinclu (Reloading Saved Controller Parameters

UNDO_PAR)

Cc thng siukhinclu gisau cng scsdnglitrong biukhnbngtay.

Schuynigiathng sPID v PI ( Changing Between PI and PIDParameters LOAD_PID (PID_ON)

Cc thng scaPI v PID clu gitrong PI_ON v PID_ON. DavoPID_ON c thsdngLOAD_PID trong chsdngthng sPI hay PID gy nhhngtibiukhin.

Lu:Thng sbiukhinchcghi trlibiukhin viUNDO_PAR v

LOAD_PID khi licabiukhinbng0.ViLOAD_PID th vng iukhinsctnh ton li:

CON_ZONE = 250/GAIN ngay ckhi CONZ_ON =FALSE.Cc khai bo thng sc ththam khotrong phnhelp caFB58 "TCONT_CP"

Documents

Module PID_F.pdf