LẬP TRÌNH labVIEW CƠ BẢN.pdf

7/21/2019 LP TRNH labVIEW C BN.pdf

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Lp trnh LabVIEWGV: Nguyn Thanh Tn

Hc phn

LP TRNH labVIEW C BN


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LabVIEW


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labVIEW


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Lp trnh

B1: Phng php pht trin phn mm

B2: Xy dng gii thut

B3: Thit k gii thutB4: Thc thi

B5: Kim tra

B6: Bo tr Sa cha

B7: To d n


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Ni dung

1. Thao tc trn labVIEW

2. K thut g ri (Debug) cho VI

3. Lp trnh theo Modul

4. Lp trnh trong VI


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Phn 1

THAO TC TRN LABVIEW


7/125Lp trnh LabVIEWGV: Nguyn Thanh Tn

Khi ng LabVIEW



Giao din labVIEW

Tham kho

Thanh menu

To new VI(Blank VI)

M file lu



To mt VI mi



Thnh phn ca mt VI

Mt VI trong labVIEW bao gm 3 thnh phn chnh:

Front panel

Block Diagram

Icon/Connector pane



Virtual Instruments (VIs)

Giao din chnhControls = Inputs (Vo)

Indicators = Outputs (Ra)

Biu khi

Cc khi chng trnh ca giao din chnh

Cc thnh phn i dy.



Icon/Connector pane

Icon: biu tng ca mt VIhay mt subVIConnector pane: Bn ch th cc input v outputca mt VI

Icon/Connector pane rt cn thit cho mt VI cngnh subVI



Giao din lp trnh



Thanh cng c



Bng cng c

LabVIEW t ng chn nhng cng c cn thit.Hin th trn Front panel v trn biu thit lp

h thng.

S dng cc cng c to v chnh sa giao dnchnh v cc i tng ca biu khi

Hin th bng cng c (Tools Palette), chn

ViewShow Tools Palette



Front panel

Lp trnh:1. Thc hin to lnh chng trnh

bng cch nhp chut phi (lycc control v indicator)

2. Chn cc i tng ph hp3. Ko v th i tng trong khung

lnh

1

2



Front panel



Front panel

-To cc lnh trn FP-Thay i nhn, chnh text v nh dng-Thay i c tnh i tng



Block diagram

Functions (Hm) nm trongBlock Diagram

Nhm to chng trnh honchnh

V d:While loop, For Loop

Whileroom is active

door is open

Loop

Webcam


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Block diagram


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Block diagram

1 Cc lin kt vi FP2 ng lnh: Truyn d liu (Wires)

3 Cc giao im trn mi i tng (Nodes)

4. Dng d liu ca i tng1

4

23


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Kiu d liu trn Block Diagram


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Block diagram

Chc nng t sp xpcc ng dy gn gng

Nhn t hp Ctrl+B xacc ng dy b t


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Terminals trong Block Diagram

Terminal l i tng tn ti trong Block Diagramln Front panel

Lun tn ti cc ng vo ra truyn thng giaFront panel v Block Diagram

Thay i kiu hin th ca cc terminals bng cchnhp phi chut v chn View as Icon


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Block Diagram

Function NodesPhn t hot ng ch yu ca labVIEW

C nn mu vng nht

Khng tn ti trong Front Panel

subVI Nodes:

subVI l nhng VI c to ra s dng cho nhng VIkhc

subVI cha Front Panel v Block Diagram ring ca nVI Express

L kiu t bit ca subVI

Nn mu xanh


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So snh

Front panel Cha cc biu tng iukhin v hin th (giao dinngi dng)

Truy cp Control Palette(chut phi)

Bao gm cc control vIndicator

Block Diagram Chc code chng trnh(lp trnh)

Truy cp Function Palette(chut phi)

Bao gm cc terminals, VIs,subVIs, functions,

constants, Structures,

wires,.


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Tm kim v Help

Tm Controls, Functions, Vis s dng nt Searchtrn Controls v Functions palette

Chn Help>>Show Context Help (Ctrl+H) hocnhp vo biu tng

Help: Search the labVIEW Help, NI Example Finder,hin th cc thng tin c bn v i tng labVIEW


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Phn 2

K THUT G RI (DEBUG)


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Vn thng gp

Dy b t (ni dy b sai kiu d liu hoc kiuvo/ra)

Mt terminal trn Block Diagram khng c ni

dyMt subVI b hng hoc do ngi dng sa i

cc Connector pane

D liu ang s dng mc nh khng chnh xc


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DEBUG

1. Execution Highlighting c s dng xemcc lung d liu chy trn Block Diagram

2. Single Stepping

Single-step: chy xuyn qua VI xem kt qu

hot ng ca mi VI trn Block Diagram Tm dng thc thi mt subVI chnh sa gi tr

cc Control v Indicator


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DEBUG

3. Probes quan st cc gi tr v d liu tc th kim tra li ng ra ca VI v function

4. Gi li gi tr trong cc dy c th quan st d

liu trn dy sau khi thc hin xong

5. Breakpoint: VI s tm dng v nt Pause s xut

hin mu ti v tr Breakpoint.


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Phn 3

LP TRNH THEO MODUL


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subVIs

Mt VI trong mt VI khc gi l subVI

Mt subVI xem nh mt chng trnh con trongngn ng dng text

Gc bn phi ca front panel v block diagram hinth Icon ca subVI

Icon xc nh cc VI khi bn t n trn s khi


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subVIs


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subVIs


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subVIs


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Icon ca subVI

Ta c th to v ty chnh Icon bng cch nhpchut phi vo biu tng gc trn bn phi cafront panel hoc block diagram v chn Edit icon

Nhp chut phi vo biu tng gc trn bn

phi ca front panel v chn Show connectorxc nh cc terminal vo/ra cho subVI


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s dng mt VI ging nh mt subVI, ta to mtIcon v Connector pane sau thit k Front panelv Blockdiagram


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To Icon

Icon: biu tng miu t gi nh ca mt VIClick chut phi ln Icon pane (Panel hocDiagram) gc ca s v chn Edit icon


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To Connector Pane

Connector pane : bn ch th cc input v outputca mt VI

Nhp chut phi vo biu tng gc trn bnphi ca front panel v chn Show connector

xc nh cc terminal vo ra

Chn im


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Tr gip v phn loi u cui

Phn loi u vo/ra:

Required Li nu khng kt ni

Recommended Cnh bo nu khng kt ni

Optional Khng c tc dng nu khng kt ni


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Tr gip v phn loi u cui


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S dng subVIs

t subVI trn block diagram:Click chn mt VI trn Function palette

Di chuyn n VI bn mun s dng nh mt subVI

Double click ln n t trong Block diagram

t mt VI ang m trn Block diagram ca VIang m khc

Click vo biu tng ca VI bn mun s dng nh mtsubVI

Ko biu tng (Icon) cho vo Block diagram ca VI khc


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To mt subVI

Chn phn no mun a vo subVI

Chn Edit>> Create SubVI


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Phn 4

LP TRNH TRONG VI


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Dataflow

LabVIEW hot ng theo kiu dataflow thc thicc chng trnh trong VI

Block diagram thc thi ph thuc vo lung d liuth Block diagram s KHNG thc thi t tri qua

phiMt nt ch c th thc hin khi d liu c snti tt c cc u vo ca n


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Dataflow

V d:Nt no thc thi trc?

a) Add

b) Subtract

c) Random Number

d) Dividee) Sine


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Cc kiu d liu trong labVIEW

Terminals: thit b u cui trc quan hin th cckiu d liu

Numeries: kiu d liu s hc hin th cc con shoc bin s (chn Representation thay i kiu

d liu numeric)


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Boolean: kiu True/False, 1/0, ng/sai

Boolean: c th l control (Knob, cng tc,..) hayhin th (led,)

C


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String: mt chui cc hin th hoc khng hin thcc k t ASCII

C ki d li l bVIEW


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Enum bao gm mt cp gi tr, mt chui v mt s,cc Enum c th l mt danh sch c xc nhbng cc gi tr

Enum lit k cc control, constant hoc indicator

C ki d li t l bVIEW


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Dynamic: kiu d liu ng lu tr cc thng tinc to ra hoc thu thp bi VI Express

Nu s dng VI thch hp th labVIEW s t ng

chuyn i thnh kiu d liu ng


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K THUT LP TRNH

Th i t Bl k Di


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Th vin trong Block Diagram

Functions\Programming:Structures: cc cu trc vng lp (while, for, case,sequence, formula, feedback,.)

Array: cc kiu trch lc, bin i, to mng,Cluster: cu trc gom nhm (bundle, unbundle,)

Numeric: s hc (ton hc, random numer, hng s)Boolean: dng logic (cng, bin i sboolean, .)String: text (string constant, bin i chui,)Comparision: cc hm so snhTiming: hm tr thi gianDialog & user..: button, thng bo, giao din,.File I/O: c, ghi file trong labVIEW.

Th i t Bl k Di


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Th vin trong Block Diagram

Measurement I/O: DAQmxData Acquisiton (thuthp d liu): DAQ Assistant

Instrument I/O: thu thp d liu qua cc giao tipni tip,

Mathematics: cc hm ton hc, tn hiu (sin,cos...)Signal Processing: tn hiu m phng, dng sng, th, lc, ph,.

Express: Input (DAQ, scope, simulate sig), signalanalysis, output, Merge signals, Arithmatic &

comparision, Timing, Structure,

Th i t F t P l


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Th vin trong Front Panel

Modern:

Numeric: s control, indicator,..

Boolean: logic (SW, button, led,)

String & path: text control, text indicator, file path,..

Array, matrix & cluster: mng control, indicator, gomnhm,

Graph: th (waveform chart, waveform graph,..)

System / Classic: cc dng control, indicator khc:

s hc, boolean, text, button, SW,Express: numeric control, numeric indicator, tex

control, text indicator, button& Swithes, led, Graph,..

While Loop


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While Loop

Whil L


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While Loop

1. Chn While Loop

2. Khoanh vng m mun

t trong vng lp

3. Ko th vo vng lpcc nt v sau i dy

Whil L


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While Loop

Bin m (Interation terminal): tr v s ln lp thc hin, bt u t zero-0

iu kin kt thc (conditional terminal): xc nhkhi vng lp dng

While Loop T nnels


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While Loop - Tunnels

Tunneltruyn d liu vo ra cho vng lp

D liu vt ra khi vng lp sau khi n chm dt

Khi mt ng d liu ni vo Tunnel ca mt vnglp, vng lp ch thc thi sau khi d liu n Tunnel

hoc d liu xut ra Tunnel sau khi kt thc vnglp

While LoopError Checking v Error


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p g

Handling

Dng mt error cluster trong while loop dngvng lp while loop nu xy ra li

For Loop


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For Loop

For Loop


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For Loop

Slnlp

Binm

For Loops Conditional Terminal


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For LoopsConditional Terminal

Conditional Terminal: iu kin dng, vng lp ForLoop s dng li khi nhn mt Boolean Conditionalhoc mt li xy ra

For Loops Conditional Terminal


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For LoopsConditional Terminal

Mt khi vung mu c gn vo ging nhwhile loop

iu kin dng nm gc phi ca vng lp

For Loops Numeric Conversion


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For LoopsNumeric Conversion

8 bytes 4 bytes

V d


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V d

So snh For Loop/ While Loop


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So snh For Loop/ While Loop

nh thi cho mt VI (Timing)


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nh thi cho mt VI (Timing)

Ti sao phi nh thi?Kim sot tn s m ti vng lp thc hin

Cung cp ti nguyn cho b vi x l v thi gian honthnh cc nhim v khc, chng hn nh tc v x l giaodin ngi dng

Timing Wait Functions


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TimingWait Functions

Mt Wait Function trong vng lp cho php VI trng thi Sleep vi thi gian c nh trc

Cho php b x l thc hin cc tc v khc trongqu trnh ch i

S dng xung ng h ca h iu hnh tnh bngms

Thanh ghi (Shift Registers)


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Thanh ghi (Shift Registers)

Thc hin vic truyn kt qu vo/ra vng lp hoct vng lp trc sang vng lp sau

Shift Registers


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Shift Registers

Click chut phi vo khung vng lp v chn AddShift RegisterThanh ghi dch bn phi s lu tr kt qu sau miln lp

Thanh ghi dch bn tri s cung cp d liu cho lnlp tip theo

Shift Registers


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Shift Registers

? ?

? ?Output=2 Output=4

Output=3 Output=5

Stacked Shift Registers


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Stacked Shift Registers

Ngn xp thanh ghi lu tr nhiu gi tr t cc lnlp trc v truyn gi tr ny n ln lp k tip

Click chut phi vo thanh ghi dch (Shift register)bn tri v chn Add Element

Nt phn hi


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Nt phn hi

S xut hin t ng trong vng lp For hoc Whilenu nh bn i dy u ra ca mt subVI,function, hoc group ca subVI v functions ti uvo ca VI tng ng, function, hoc group.

D liu lu tr khi m hon tt mt vng lp, gid liu ti vng lp k tip v truyn i mi kiu dliu.

Nt phn hi


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Nt phn hi

i dy t u ra ti u

vo c t ng to ra

mt nt phn hi

t mt nt phnhi t bng Functions

Structures

Cu trc Case


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Cu trc Case

Thc hin v hin th ch c mt trng hp hocmt s con trong mt thi im

Ng vo s xc nh cho php trng hp no hays no c thc thi

Cu trc Case cng tng t nh cu trcIf..then..elsetrong cc ngn ng lp trnh dng text

Cu trc Case


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Cu trc Case

Case Selector Label: cha tn ca trng hin ti

Cu trc Case


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Cu trc Case

u vo lun c sn cho tt c cc trng hp

Phi xc nh mi u ra tunnel cho mi trnghp

Cu trc Case - Default


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Cu trc Case Default

Nu ng vo khng ri vo bt k trng hp noth cu trc Case s thc hin chng trnh mcnh (default)

Nu khng c dy no a vo th cc kiu d liu

s c default theo bng sau:

Cu trc Case - Boolean


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Cu trc Case Boolean

Ng vo l Boolean ch to ra hai trng hp: Truehoc False

Cu trc Case - Integer


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Cu trc Case Integer

Ta c mi trng hp (case) cho mi s nguyn

Nu s nguyn m khng c mt trng hp cxc nh th t ng chn trng hp mc nh

Cu trc Case - String


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Cu trc Case String

Mi trng hp tng ng vi mt chui nht nh

Chui khng xc nh th n s chn trng hpmc nh

Cu trc Case - Enum


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Cu trc Case Enum

Cung cp cho ngi dng mt danh sch cc bngghi chn

Cu trc Case Error Checking vE H dli


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Error Handling

S dng cu trc Case trong VI thc thi chngtrnh khi khng c li, v b qua chng trnh khi cli pht sinh

Mng (Arrays)


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Mng (Arrays)

Mt mng (Array) c trng bi kch thc v phnt trong n

Phn t (Element): d liu nm trong mng

Kch thc: chiu di v chiu rng, ct x hng y

Mng c th c mt hoc nhiu chiu v c (2^31-1)phn t trn mi chiu

Mng s dng mt tp hp cng kiu d liu vcc php ton mang tnh lp li nhiu ln

To mng


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To mng

1. t mt mng trng (array shell) ln front panel

2. Ko hoc th i tng hoc phn t vo arrayshell

3. V d: mng hng

ArrayAuto Idexing


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ay uto de g

Khi ch Auto index c m ng ra tunnel,mng ng ra nhn tng phn t mi mi vng

Mng to ra lun c kch thc (s phn t) bngvi s ln thc thi ca vng lp

Click chut phi ln tunnel v chn enable/disableauto - indexing

Mng 2D


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g

Lu tr cc phn t dng li

to mng a chiu: click chut phi vo indexdisplay v chn Add Dimention

Mng chakhi to

Mng khito gi tr ban

u

To mng 2D


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g

C th to 2 vng lp For loop lng vo nhau to

mng 2D

Array


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y

ClustersKiu gom nhm


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g

Clusters l tp hp nhiu kiu d liu khc nhau

Dng hm Bundle hoc Unbundle t hp hocphn gii mt Cluster

To mt Cluster


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to mt Cluster control hoc indicator trn frontpanel:

t mt cluster shell trn front panel

Ko th cc i tng hoc phn t vo cluster shell nh:numeric, boolean, string, path, refnum, array,

Error Cluster


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LabVIEW s dng error cluster chc thng tin li

Mt error cluster cha cc phn t sau:Status: kiu boolean, tr v True nu khng c li vngc li

Code: kiu 32 bits Signed integer xc nh m liSource: kiu string xc nh ni b li

So snh vi Array


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y

Ging nhau: c control hoc indicator nhng ng

thi khng cha c hai

Cluster c kch thc thay i so vi kch thc cnh ca array

Cluster cha nhiu kiu d liu khc nhau; cnarray ch cha mt kiu d liu duy nht


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MT S K THUTTHNG DNG

Lp trnh phn on (SequentialProgramming)


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Programming)

Cc VI bnvitsc thchinmtcch tun

t

Khng c bt k s u tin no trong blockdiagram, v khng bitcci no trcci no

sau.



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Programming)

S dng error clusters u tin qu trnh thc thi



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Programming)

S dng cu trc on (Sequence structure) u

tin thc thiMt cu trc vi cc khung (frames), Mi khung s cha

mt tc v

Khung th 2 khng th thc thi cho n khi mi th trongkhung th nht hon thnh



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Programming)

Trnh s dng qu nhiu cu trc phn on

Bn khng th dng thc thi mt thnh phn trongmt on



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Programming)

Cch tt nht vit VI ny l nh km cc hp

thoi trong cu trc Case, dy error cluster sc ni ti b chn ca cu trc case(caseselectors)

Trng thi my (State Machines)


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Lp trnh trng thi(State Programming) l mu

thit k nhm thc hin mt s trng thi hocmt lu

Khi no s dng state machines?

Thng c s dng to cc giao din, i vimi ngi dng khc nhau th s c giao din khcnhau

Thng c s dng th nghim qu trnh,trong mi trng thi i din mi phn on caqu trnh.

Trng thi my (State Machines)


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Mt state machine bao gm nhiu trng thi v

mt chc nng chuyn tip n cc trng thi ktip

Mi trng thi c th dn ti mt hoc trng thi

hoc kt thc qu trnh thc thi

File I/O


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File I/O c v ghi vo mt file

Mt phng php in hnh truy xut file:

nh dng File(File Formats)


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(File Formats)

LabVIEW c th s dng hoc to ra cc nh

dng tp tin sau y:Binaryl kiu nh dng cp thp cho tt c cc

nh dng khc s dng

ASCIIL kiu t bit ca binary file, l nh dngtiu chun cho hu ht tt c chng trnh

LVMLabVIEW measurement data file (.lvm)nhdng ca LabVIEW, cha bn tnh v vn bn

TDMSMt kiu file Binary c to bi cc snphm ca NI bao gm 2 file tch ri: Mt binary filev mt binary index file

nh dng File(File Formats)


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(File Formats)

Trong phn ny, tp trung vo vic to text

(ASCII) filesS dng cc Text file trong cc tnh hung sauy :

Truy xut cc tp tin t cc ng dng khc Khng quan tm n b nh trng, v tc I/Oca file

Khng nn truy xut dng random read hocwrite

High-level File I/O


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High-level VIs truy xut I/O file phi qua 3 bc chungKhng hiu qu cho vic cu hnh hoc thit k cho cc

tnh nng ring ca file

Low-level VIsVI ring bit cho mi bcNu ghi file trong mt vng lp, s dng hm low-level

file I/O

High-Level File I/O


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Write to Spreadsheet File

Chuyn i mt mng dng double-precision ntext string v ghi string ny n ASCII file

Read From Spreadsheet File

c cc gi tr s theo dng (line) hoc hng(row) t mt text file cha s v xut ra ngoi mtmng 2D array vi cc phn t dng s double-precision

Write to/Read from Measurement File

Mt dng Express VI cho php ghi (write), c(read) mt LVM hay TDMS file

Low-Level File I/O VIs


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Variable


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Cannot pass data between parallel loops with a

wire

Variables allow you to circumvent normal dataflow

by passing data from one place to another without

connecting the two places with a wire

Variable


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Variables are block diagram elements that allow

you to access or store data in another location

Variables can be of the following types:

Local: store data in front panel controls and

indicators Global: store data in special repositoriesthat can be accessed from multiple VIs

Functional Global: store data in While Loop shiftregisters

Shared: transfers data between various distributedtargets connected together over a network

Local Variable


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Use local variables to pass data within a single VI

Global Variable


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Use a global variable or a single process shared

variable to share data between multiple VIs

Use a global variable to share data among VIs on

the same computer, especially if you do not use a

project fileUse a single process shared variable if you may

need to share the variable information among VIs

on multiple computers in the future

Property Node


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Property Nodes access the properties of an object

In some applications, you might want to modify the

appearance of front panel objects programmatically

in response to certain inputs

If a user enters an invalid password, you might wanta red LED to start blinking

If a data point is above a certain value, you mightwant to show a red trace instead of a green one

Property Nodes allow you to make these

modifications programmatically

Property Node


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Property Nodes execute in order from top to bottom

If an error occurs on a terminal, the node stops at

that terminal, returns an error, and does not execute

any further terminals

Control References


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A control reference is a reference to a front panel

object

Wire control references to generic Property Nodes

Pass control references to subVI

Control References


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Control References


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Invoke Nodes


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Invoke Nodes access the methods of an object

Use the Invoke Node to perform actions, or

methods, on an application or VI

Unlike the Property Node, a single Invoke Node

executes only a single method on an application orVI

Invoke Nodes


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To create an implicitly-linked Invoke Node, right-

click the control and select CreateInvoke Nodeand choose a method

An example of a method that is common to all

controls is the Reinitialize to Default methodThe Waveform Graph has the method Export

Image:

Events Programming


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Events Programming


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Examples of User Interface (Static) Events

Pressing a button on the mouse, moves or clicks themouse

Pressing a key on the keyboard

Value (Signaling) Property can generate aprogrammatic event

USB 6008


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THANK YOU!

Documents

LẬP TRÌNH labVIEW CƠ BẢN.pdf