Introduction to Labview (1)

7/17/2019 Introduction to Labview (1)

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Introduction to LabVIEWES110



Graphical programming language

& Data flow LabVIEW relies on graphical symbols rather

than textual language to describe

programming actions The principle of dataflow in which functions

execute only after recei!ing the necessary

data go!erns execution in a straightforwardmanner



"ow does LabVIEW wor#$ LabVIEW programs are called%

Virtual Instruments (VIs)

because their appearance and operationimitate actual instruments

"owe!er they are analogous to main

programs functions and subroutines from popular language li#e ' (ortran )ascal *



Front Panel• Controls = Inputs• Indicators = Outputs

Block Diagram• Accompanying “program”

for front panel• Components “wired”

togeter

LabVIEW )rograms +re 'alled Virtual

Instruments ,VIs-



LabVIEW Introduction Two .sets/ for de!elopment

(ront )anel

0loc# Diagram

Wiring connections

LabVIEW 'on!entions

1unning LabVIEW programs



LabVIEW (ront )anel +ll user interface

goes here2

3sed to display

'ontrols or

Indicators

"ighly

customi4able



LabVIEW 0loc# Diagram +ctual program

In!isible to user

1ead left to rightli#e a boo#

Where the5+GI'happens2



TerminalsWhen you place a control

,or indicator - on the

(167T )+7EL

LabVIEW automatically

creates a correspondingcontrol ,or indicator -

terminal on the 0L6'8

DI+G1+5



'ontrol$ or Indicator$

Controls 9 Inputs from the user 9 :ource Terminals

Indicators 9 6utputs to the user 9 Destinations



5anipulating 'ontrols and

Indicators 1ight clic# on an indicator to

'hange to control

'hange format or precision

1ight clic# on a control to

'hange to indicator

'hange mechanical action ,whether to latch

open or closed and what to use as default*-



Wiring 'onnections Wires transport data

through the bloc#

diagram

Wire color indicates

!ariable type

+ red .;/ means

something is wrong2



Wires

+ LabVIEW VI is held together by wires connecting nodes

and terminals< they deli!er data from one source terminal to

one or more destination terminals



0ro#en wiresIf you connect more than

one source or no source

at all to a wire

LabVIEW

DI:+G1EE: with whatyou=re doing and the

wire will appear broken



5essy !s 'lean Wiring

CLEAN: Easy to troubleshoot

MESSY: What is going on?



0asic wires used in bloc# diagrams

and corresponding typesEach wire has different style or color depending on the data

type that flows through the wire%

:calar >D array ?D array 'olor

(loating@pointnumber

orange

Integer number blue

0oolean green

:tring pin#



LabVIEW 'on!entions (ront panel items

'ontrols and indicators

0loc# diagram items )rogram structures ,loops case structures math etc-

'ontrols !s Indicators Wires attach to controls on the right ,gi!e !alues-

Wires attach to indicators on the left ,recei!e !alues-

Wiring colors Wires are color coded to correspond to data types



1unning LabVIEW )rograms +L56:T +LW+A: put

your program in some sort

of loop that can be stoppedwith a control

+V6ID using the red .x/ tostop your program



Lab EBuipment

6scilloscope

(unction Generator

Digital Voltmeter ,DV5-

Universal Measuring

nstru!ents

Signal "enerator



+ddCedit text

Wire features together to

control flow of data

:elect a feature to

edit or mo!e

6perate a control

)robe Data

,troubleshoot-



Insert a digital

indicator or control

Insert a boolean control

,button or switch-



+dd a structure such as forwhile and case statements

+dd a numeric

operator ,@*-

(ile IC6

+dd a boolean

operator ,and or*-

Data +cBuisition

:ignal analysis

'omparison

5athematical

(unctions

TimingCdialog





1eorder

obects

1un

'ontinuous run

)ause:top

(ont ring

+lignment ring

Distribution ring

Debugging features

more on this later…



The 1un 0utton

The 1un button which loo#s

li#e an arrow starts VI

execution when you clic# on it

It changes appearance when a

VI is actually running

When a VI won=t compile the

run button is bro#en



Examples



Control

#er!inals

Block Diagram !indow

Front Panel !indow

n$i%ator#er!inals

'reating a VI



Example >% 'raps

(rom the functions F numeric

panel insert a pair of dice

(rom the 'ontrols panel insert a

numeric digital indicator ,on the

front panel-

3se the wiring tool to connect

the two ,in the wiring diagram-

and clic# the .run/ button

repeatedly

7umbers from to >

should be displayed in the front

panel



Example >% 'raps ,continued-

Delete the wire

+dd a multiplication node and anumeric constant to allowmultiplication by H

+dd an addition node and numericconstant to allow addition of >

+dd a mathematical .1ound to 7earest/ node

5a#e a second copy of thisstructure to represent a second dieand wire them together through anaddition node with an output to anumeric constant

This wiring diagram simulates the rolling

of ? dice and their addition to form a number

from ? through >?



Example ?% +nalog & Digital

Voltmeter (simulated signal)

3niform noise used as simulated signal F(unctions F :ignal )rocessing F :ignalGeneration menu

+bsolute !alue function from functions Fnumeric menu

5ean !alue of data series from thefunctions F mathematics F )robability and:tatistics menu

The ?H ms wait implemented from thetime and dialog menu slows the .flutter/of the meter



Example % 1eading an analog input signal

Requires A/D board to implement (rom the functions menu select

data acBuisition and then

analog input Then select either

.:ample 'hannel/ or :ample

'hannels/

This places the sampling icon

in your wiring diagram

Aou then need to configure the

channel,s- and wire the output

to other parts of your program



Example J% :ignal +nalysis ,continued-



Example H% 'reating :ub@VIs

In wiring diagram useselection tool ,mouse box- toselect all items to be in the

:ubVI (rom Edit menu select .'reate

:ubVI/

Double clic# on new icon andsa!e it as a separate VI

'ut@and@paste it at will orinsert it using .(unctions F:elect VI menu/

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Introduction to Labview (1)