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Workshop3 of 7

Welcome!

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Today's Topics

Review of Workshop 2

Diagram Disable Structure

Conditional Structure

Event Structure

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Review Question 1

If I add a new element to an enum that is saved ina *.ctl file, how would the file need to be saved inorder to update all of instances

a) Custom control

b) Strict Type Definition

c) Type Definition

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Review Question 1

If I add a new element to an enum that is saved ina *.ctl file, how would the file need to be saved inorder to update all of instances

a) Custom control

b) Strict Type Definition

c) Type Definition

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Review Question 2

Which of the following always remain unique toeach instance?

a) Label

b) Default value

c) Size

d) Data type

e) Representation (numerics)f) Description

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Review Question 2

Which of the following always remain unique toeach instance?

a) Label

b) Default value

c) Size

d) Data type

e) Representation (numerics)f) Description

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Review Question 3

True or False?

A custom control can only be used for the projectwithin which it was created.

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Review Question 3

True or False?

A custom control can only be used for the projectwithin which it was created.

FALSE

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Diagram Disable Structure

Use to disable a section of code on the block diagram

Multiple subdiagrams possible maximum of one enabled

Disabled subdiagrams appear grayed out

Great tool for troubleshootingdont have to re-write code

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Conditional Disable Structure

Use to define conditions that indicate which code on theblock diagram executes

Examples:

If running as an executable, then programmatically close

LabVIEW when VI finishes

If running on Windows, look for file here; if running on Mac OSXthen look here.

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Events

Event An asynchronous notification thatsomething has occurred

Events originate from the user interface, external I/O, orother parts of the program

Example events:

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Button click Value change

Mouse over Key press

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Event Structure

Event Structure LabVIEWs programmatic toolfor handling events.

Therefore, execution of code can be dependent

on whether or not an event has occurred

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Waits for an event to

occur indefinitely,

unless configured totimeout.

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Parts of an Event Structure

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Timeout Event Selector Label

Event Data Node Event Filter Node

Event Data NodeIdentifies the data

LabVIEW provides

when the event occurs;

similar to the Unbundle

By Name function

Event Filter Node

Identifies the subset of

data available in theEvent Data node that

the event case can

modify

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Notify Events User action has already occurred LabVIEW has processed the eventAvailable only in the Event Data node

Filter Events User action has already occurred LabVIEW has NOT processed the eventAllows you to override default behavior for eventAvailable in the Event Filter node and Event Data node

Notify and Filter Events

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Right-click theborder and selectEdit EventsHandled by ThisCase

To Configure an Event Structure

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EventsEvent

Sources

Configured

Events

Configuring Event Structures

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Notify Events (green arrow)

User action has already occurred

Filter Events (red arrow)User performed action but event is notprocessed. Allows you to customize eventhandling.

Notify and Filter Events in Config. Window

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Normally used in aWhile Loop

Control/Indicator theevent configured for isoften placed insidethat event case

Event structurehandles exactly oneevent per iteration

Sleeps when noevents occur

Using Event Structures

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Event Structures Tips

If no timeout is configured and an event neveroccurs stuck waiting indefinitely, must abortVI; therefore, wire the timeout terminal with a

value other than -1 (at least while developing) heavy code within the Event Structure causes

the front panel to lock up, often confusing theuser try to keep code in an event case to a

minimum

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Demonstration:

Configuring an Event

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Create a VI that uses events

Homework