Vi Presentation

8/8/2019 Vi Presentation

1/64

Virtual Instrumentation and Data

Acquisition Using LabVIEW


2/64

Out line of the Presentation

About Bench top/Traditional Instruments

Introduction to Virtual Instrumentation

LabVIEW Concepts.

Data Acquisition with Hardware


3/64


4/64

What is Virtual Instrumentation ?

It is an interdisciplinaryfield that merges sensing, hardware, andsoftware.

Virtual instrumentation is defined as the combination ofmeasurement and control hardware and application softwarewith industry-standard computer to create user-defined

instrumentation systems.

Virtual Instrumentation sets a new standard in measurement by replacingbench top instruments

Creates flexible and sophisticatedinstruments for control and monitoringapplications.

A Paradigm shift from Hardware centric to Software centric


5/64

--- cont

Virtual Instrument What does it mean?


6/64

--- cont

Virtual Instruments constructed with software are

--Inexpensive.--More Accurate.

--Maintenance free.

--Can sense different physical quantities.

Virtual Instrumentation--Works fast--Handles repetitive tasks

--Process data

--Stores results--Generates reports

--Increases test safety

--Controllable by the user


7/64

VI Approach

Popular softwares in VI are

(a) LabVIEW (b) LabWindows/CVI

(c ) HP-VEE (d) Test stand

(e) Measurement studio.

Hard Ware

SCC/DAQPC

Soft Ware


8/64

Traditional Vs Virtual Instruments


9/64

LabVIEW

Laboratory Virtual Instrumentation EngineeringWorkbench


10/64

What to EXPECT?

Learn what are virtual instruments and how LabVIEW can used

to create VIs

Understand user interface offerd by LabVIEWand methods of

programming.

Create applications using Data Acquisition(DAQ) boards.


11/64

What Not To Expect?

Programming Theory

Using of every built- in LabVIEW object,function or library VI.

How to develop an instrument driver


12/64

What is Virtual Instrument(VI)?

A small piece of code in VI software/ A small program

VI has

-- Front panel

-- Block Daigram--Icon

-- Connector pane


13/64

LabVIEW Basics


14/64


15/64


16/64

Controls and Functions Palettes

Controls Inputs fromthe User

IndicatorsOutputs to

the User

Contorls palette

(Front Panel Window)

Functions palette

(Block Diagram Window)


17/64

Basic blocks of Block diagram

Terminals---These are entryand exit ports that exchange

information between the front

panel and block diagram.

.Nodes ---A node is just a fancyword for a program execution

element.

WiresWires are the datapaths between source and

destination terminal.

Data type & representation


18/64

Numeric Data Representations


19/64

Data Types


20/64

Express VIs VIs and Functions

Express VI--- interactiveVIs with configurable

dialog page.

StandardVI--- modular

VIs customized by

wiring

Functions--- fundamentaloperating elements of

LabVIEW,


21/64

--- contd


22/64

Creation of VI

Step1: Open blank/new VI.

Step2: Create Front panel.

Step3: Create Block diagram.

Step4: Run the VI.


23/64


24/64


25/64

Data flow programming LabVIEW follows a data flow model for running VIs.

In control fow, the sequential orderof program elements

determines the execution orderof a program.


26/64

LabVIEW Functional Elements


27/64

Loops and Structures


28/64

Loops with Shift registers


29/64

--- cont


30/64

Case & Sequence Structures & Formula

nodes

Case structure Sequence structure


31/64

Formula Node

The Formula Node is a resizable boxthat is used to enter

algebraic formulas directly into the block diagram.

The Formula Node is a convenient text-based node used to

perform mathematical operations on the block diagram.

Formula Nodes are useful forequations that have many

variables.


32/64

Arrays and Clusters

Array--- group of similar data elements.


33/64

--- cont


34/64

Cluster


35/64


36/64

Wave form charts


37/64

Wiring data into charts


38/64

File I/O

File I/O --- passing data to and from files.

--- Files can binary, text or spread sheet.

--- Write/ Read LabVIEW measurement files.

Writing to LVM file Read from LVM file


39/64

Debugging Techniques

Finding errors -- Click on broken Run buttonWindow showing error appears

Execution Highlighting

--- the user can view an animation of VI block diagram execution.--- As data is passed from one node to another, bubbles moving

along the wires indicate the movement of data.

--- highlighting greatly reduces the performance of a VI.

. Probes --- The probe is used to check intermediate values in aVI that executes


40/64

--- cont


41/64

Sub VI

What is Sub VI?

Making an icon & connector pane for subVI

Using VI as Sub VI

--- cond


42/64

Sub VI

-- contd


43/64

-- cont

Normal VIs block diagram Sub VIs block diagram


44/64

Creation of SubVI

Step1 Edit icon

Step2 Create the connector pane

Step3 Assign terminals

Step4 Save the VI

Step5 Call the VI


45/64

--- contd


46/64

--- cont


47/64


48/64


49/64


50/64


51/64

D A i i i


52/64

Data Acquisition

DAQ Device

Computer

Terminal Block

Sensors

Cable


53/64

Data Acquisition Terminology

Resolution - Determines How Many Different VoltageChanges Can Be Measured

Larger Resolution More Precise Representation of Signal

Range - Minimum and Maximum Voltages

Smaller range

More Precise Representation of Signal

Gain - Amplifies or Attenuates Signal for Best Fit in Range

t


54/64

--- cont

t


55/64

--- cont

cont


56/64

--- cont


57/64

HardwareBNC-2120

NI-ELVIS


58/64

Basic Programming Architecture

Simple VI Architecture.

General VI Architecture

State Machine Architecture


59/64


60/64

General VI Architecture


61/64

State machine Architecture

R t F t P l


62/64

Remote Front Panels


63/64


64/64

Vi Presentation

Documents

Transcript of Vi Presentation