Bai Tap Thuc Hanh Labview 9906

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Bi 1. Cc vng lp v chartA. L Thuyt1. Vng lp While

Thc thi lnh cho n khi gp iu kin dng. Trong Block Diagram, chn Functions > Structures, dng tr chut click v chn ng bin vng lp sao cho bao quanh on code cn thc hin. Vng lp While thc thi chng trnh bn trong vng lp cho n khi conditional terminal nhn 1 gi tr Boolean nht nh no . Khi iu kin dng l Continue If True, vng lp While s thc thi chng trnh cho n khi conditional terminal nhn gi tr False. Iteration Terminal biu th s ln lp li thc hin xong. Khi thc hin vng lp ln th nht, Iteration Terminal tr li gi tr l 0.

Block diagram sau cho ta thy, vng lp While thc thi chng trnh cho n khi gi tr ng ra t SubVI nh hn 10 hay iu khin Enable c gi tr l False.

Ngc li, ta c th thay i hot ng ca conditional terminal bng cch click phi chut hay ng bin ca vng lp While v chn Stop If True. Vng lp s ngng cho n khi conditional terminal nhn gi tr TRUE nh hnh sau.

2. Waveform Chart Chn Controls > Graph palette . Waveform chart cho php hin th cng lc 1 hay nhiu plot, mt hay nhiu tn hiu nh sau: Chart c 3 kiu khc nhau hin th data. Click phi chut, chn Advanced > Update Mode, chn Strip Chart, Scope Chart hay Sweep Chart. Kiu mc nh l Strip Chart. Strip Chart: hin th d liu ang running lin tc t tri sang phi

Scope Chart: hin th mt phn ca d liu t tri sang phi

Sweep Chart: tng t nh Scope ch hin th mt phn ca d liu nhng li hin th data c bn phi v data mi bn tri ngn cch vi nhau bi 1 vch thng ng nh hnh sau:

Trong Block Diagram, ta c th ni trc tip ng ra scalar n 1 waveform chart nh sau:

hin th nhiu plot cng lc, chn Functions > Cluster . C th thm nhiu plot bng cch thay i li kch thc ca Bundle nh hnh sau:

3. Thanh ghi dch (shift registers) Vi cc vng lp While v For, ta c th s dng Shift register truyn gi tr t 1 vng lp ny n vng lp khc. to shift register, click phi chut ti ng bin ca vng lp v chn Add shift register. Shift register cha 2 terminal ngc nhau trn ng bin ca vng lp nh hnh sau:

Terminal bn phi cha gi tr d liu sau khi hon tt 1 vng lp, sau d liu ny c dch khi kt thc vng lp v n xut hin ti terminal bn tri bt u 1 vng lp mi nh hnh sau:

Mt shift register c th lu tr bt k loi d liu no: numeric, boolean, string, array. Ta c th cu hnh shift register lu tr cc gi tr t cc vng lp trc, thun li khi chng ta cn tnh tr trung bnh ca cc im gi tr. to thm cc terminal cho php truy xut cc gi tr t cc vng lp trc , click phi chut vo terminal bn tri v chn Add Element.

khi to thanh ghi dch vi 1 gi tr cho trc bn ngoi vng lp, ta ni gi tr khi to ny vi terminal bn tri ca shift register. Gi tr khi to chnh l gi tr mc nh cho loi d liu ca shift register. Nu loi d liu ca shift register l Boolean th gi tr khi to c gi tr l False. Nu shift register c loi d liu l numeric th gi tr khi to l 0.

4. Vng lp For

Khc vi vng lp While thc thi chng trnh cho n khi gp gp iu kin dng, vng lp For thc thi chng trnh vi s ln lp li cho trc. Vng lp For gm 2 terminal: count terminal nh s ln thc thi chng trnh v iteration terminal biu hin s ln lp thc hin xong.

B. Thc hnhBi 1.a. Thc hin chng trnh s dng vng lp While to tn hiu ngu nhin v hin th trn Scope Chart nh sau:

c Block diagram nh sau:

Hng dn: Chn Waveform Chart, click phi chut, chn Visible Item > Plot Legend cho php n legend

Chn trc x-axis, click phi chut, chn Visible Scale Label xa label ca trc x.

Chn Functions > Time & Dialog, nh thi gian thc hin 1 vng lp. Functions > Numeric, chn hm Random number.

b. Thc hin chng trnh to 1 s ngu nhin n khi bng vi 1 gi tr cho trc c Front Panel v Block Diagram nh sau:

Hng dn:

Number to match control ch r gi tr cn t n Current Number indicator hin th gi tr ngu nhin hin thi

# iteration hin th s ln lp li trc khi bng vi gi tr cn.

Thit lp data range cho Number to match control: 0 10000.

Thit lp chnh xc cho cc controls v indicators.

Chy chng trnh vi number to match control: 50, 100, 11000. Nhn xt?

Bi 2. Thc hin chng trnh ng dng shift register nh sau:

Bi 3. Thc hin chng trnh s dng vng lp For nh sau:a. To 100 s ngu nhin v xut ra waveform chart.

b. Thc hin VI biu din 2 plot ngu nhin trn Sweep chart: plot biu din tn hiu ngu nhin v 1 plot cn li biu din tr trung bnh ca 4 gi tr trc .

Hng dn:

S dng vng lp For (N = 200)

S dng 3 terminal bn tri ly tr trung bnh ca 4 gi tr d liu trc .

Chn Functions > Cluster nhm gi tr ngu nhin v tr trung bnh trc khi v chng trn cng 1 chart.

Bi 4. Ch s dng vng lp While, kt hp vng lp While v For sao cho chng trnh dng li khi n t n gi tr cho trc trn control panel hoc khi bt nt Stop.Bi 2. Mng, gin v cu trc Cluster

A. L thuyt1. Array.Mng l tp hp cc phn t d liu cng loi (numeric, string, Boolean, cluster). Mt mng c th l 1 hay nhiu chiu, mi chiu c n 231 phn t.

Cc bc to array control hay indicator:

Chn Controls > Array & Cluster

Drag chn i tng d liu vo bn trong phn t array.

Mng 2 chiu cn 2 ch s hng v ct.

To array constant:Chn Functions > Array. Drag cc i tng d liu vi cc loi khc nhau vo array shell:

2. Graph: Gin cho php biu th d liu 2D hay nhiu hn na. C 2 loi l XY graph v waveform graph. 3. Cluster Cluster l loi cu trc d liu kt hp mt hay nhiu thnh phn d liu thnh 1 loi d liu mi. Cluster khc vi array l cc thnh phn hnh thnh nn cluster c th l cc loi d liu khc nhau nh Boolean, String, Numeric. To Cluster control hay indicator: Controls > Array & Cluster. Tt c cc i tng d liu trong cng 1 cluster phi hon ton l controls hoc hon ton l indicator.

to 1 cluster constant, chn Functions > Cluster > Cluster Constant.

Cn lu th t ca cc i tng d liu trong 1 cluster. Mun thay i th t, click phi chut, chn Reorder Controls in Cluster.

B. Thc hnh

Bi 1. Thc hin array s dng cc vng lpa. Thc hin array 1 chiu s dng vng lp For/While s dng kh nng auto-indexing

b. Click phi chut trn ng bin ca vng lp, chn Disable Indexing. Cho bit kt qu?

c. To array 2 chiu:

Bi 2. Thc hin mt s chc nng ca arraya. Chc nng Array size:

b. Chc nng Initialize array:

c. Chc nng Build array:

d. Chc nng Array subset

e. Chc nng Array index

Bi 3. Thc hin VI sau:

Bi 4. Vit VI o ngc 1 mng n phn t to trc, vd: a[0] a[n-1], a[1] a[n-2],

Bi 5. Thc hin cc gin saua. Gin trnh by 1 plot duy nht:

b. Gin trnh by nhiu plot:

c. XY graph:

Bi 6. Thc hin VI sau:a.

b. Bi 3. Cu trc case v chui

A. L thuyt.1. Cu trc CaseChn Functions > Structures, Case. Ty thuc vo selector terminal: nu l numeric hay string s c 231 1 trng hp cho cu trc Case, nu l Boolean th c 2 trng hp True v False.

2. Chui: Thc hin chng trnh theo trnh t3. Formula Node: Thc hin cc biu thc a bin v phc tp mt cch n gin hn

( Chn Functions > Structures > Formula Node. Click phi chut trn ng bin, chn Add Input/ Add Output to cc bin u vo v bin ng ra. Cc biu thc trong Node cch nhau bi du chm phy. B. Thc hnh

Bi 1. Thc hin cc VI saua.

b.

Bi 2. Thc hin VI sau:

Hng dn: Thc hin chng trnh trong vng lp While trc.

Chn Functions > Structures > Sequence Structure bao quanh on code va thc hin. Click phi chut vo ng bin, chn Add Frame After.

Chn frame cha vng lp While, click phi chut, chn Make This Frame >>0.

Chn Functions > Time & Dialog > Tick count: c gi tr hin thi ca ng h h thng.

Bi 3. Thc hin cc Formula Node nh saua.

b. V graph biu th phng trnh sau: y = f(x)^3 + f(x) vi f(x) = tanh(x) + cos(x).

Bi 4.

a. Ch s dng 1 Formula Node gii 2 phng trnh sau:

b. Thc hin Front Panel gm 2 ng vo v 1 indicator biu din kt qu cc php ton: cng, tr, nhn chia t 2 gi tr ng vo.c. Thc hin chng trnh gm 2 ng vo: 1 l gi tr ngng v 1 input aray. Mt ng ra biu din gi tr ng vo b hn gi tr ngng cho trc.

Bi 4. String v file I/O

A. L thuyt1. String

String l chui cc k t ASCII c th hoc khng th hin th. String l kiu d liu khng ph thuc platform.

String c dng : To thng bo dng text, chuyn d liu dng s thnh chui truyn v chuyn ngc li khi x l, lu thng tin vo file, to hng dn hoc nhc nh trong hp thoi.

Trn Front Panel, String c th xut hin Text Entry Box, Table hoc Label

Cc kiu hin th String: Normarl display, Code display, Password display v Hex display.

To String, Controls > String & Path

2. File I/O:Cho php lu tr hay thu nhn thng tin t file hoc a khc. Chn Functions > File I/O. Labview h tr rt nhiu hm cho cc thao tc file I/O. Chia lm 3 loi sau:

Loi High-Level File Vis Loi Imtermediate File Functions Loi Advanced File Functions: B. Thc hnhBi 1: Thc hin cc chc nng ca String:a. String length:

b. Concatenate Strings:

c. String Subset:

d. Math Pattern:

e. Chuyn t string sang s

f. Chuyn t s sang string

Bi 2. Thc hin VI sau

Bi 3. Thc hin VI saua. Write function

b. Read functions:

Bi 4. Thc hin VI sau:

Hng dn: Chn Analyze > Signal Processing > Signal Generation cho Sine pattern, Uniform White Noise.

Chn Functions > Array cho Transpose 2D Array

Bi 5. Thc hin VI sau: