LabVIEW

modularity

change to one module has minimal impact on other modules aka subvis

type definition control

changes all instances of a linked control in a single edit

waveform data type is most similar to...?

cluster

controls vs functions palette

controls palette is for front panel functions palette is for block diagram

Error handling code

does NOT display dialog box us

Error vs. warming

error: status= true warning: status= false, code is non-zero

explicit vs. implicit for property/invoke nodes

explicit requires reference implicit requires color/label

what is iteration when for loop sum is 1? 2?

for 1, iteration is 0 for 2, iteration is 1

Most efficient method for creating array...?

for loop with auto-indexing (default)

methods

functions that operate on the object

what is the best function to use for extended periods of time?

getdate/timeinseconds

color label is...!?!?

implicitly linked

how do you know if an array is initialized or uninitialized?

initialized will have white background and uninitialized will be grayed out

Bold=

input required, broken run arrow wil result

inputs and outpouts

inputs=controls (knobs, push buttons) outpouts= indicators (graphs, LEDs)

I16 symbol=

integer

local variable

-allow data to be passed between parallel loops -single vi, tied to a front panel -control/indicator

error handling code does NOT...

-display dialog box used to correct broken vi - generate user-defined error code

Multiple loop design pattern allows you to...

-execute multiples tasks at different rates

polymorphism

-feature that allows values of different data types to be handled using a uniform interface - automatically accepts input data of different data types ex: (array of clusters)+ (cluster)= array of clusters

timing function

-provides processor time to complete other tasks -uses ms clock

Different between U and I

...

Types of loops

...

coercion dots

...

match pattern

...

time stamp

...

unsigned= ...?

0-255

debugging tools

1. highlight execution 2. probes to see current value in wire 3. breakpoints to pause execution at specific point 4. single-step through code

State machine

- case structure inside while loop - cannot stop execution in middle of sequence

Property nodes allow you to...

- change color of a chart plot - disable and enable controls - get the location of a control or indicator - allow you to programmatically modify appearance of front panel objects

Array

- controls or indicators - # of elements includes 0 - grayed out=uninitialized - wire thickness associates with dimension

error handling code

- displays a dialog box when an error occurs - transitions state machine to shutdown state when error occurs

what is a flat sequence structure?

- executes each frame beginning with left-most frame; previous frame must complete before next frame executes

stacked sequence structure

- executes frame 0, then frame 1, etc. until last frame executes - can only see one frame at a time - sequence local transfers data from frame to frame (boxed thick arrow)

examples of VI methods

- front panel: center - default values: reinitialize all to default -print: VI to HTML

control references are wired to...?

- property or invoke nodes - CF= reference to a front panel object

execution timing

- provides design pattern with a function that specifically allows processor time to complete other tasks - sometimes does not need Wait function

notifier vs. queue

- queue BUFFERS data - notifier does not

string

- receives text from user - (ex: labels) - pink color

Enum

- represents a pair of values (string and numeric) - used in state machine - appears as string to me and number to computer - ex: months

notifier

- sends alert to help control timing of PARALLEL loops - transfer data between loops - exclamation point - used with master/slave

Queue

- transfers ALL data between loops - helps control timing of parallel loops - ensures that no data is lost - "blocky" thing

invoke node

- used to perform actions (methods) on referenced items (VI, control) - format and precision - reinitialize to default value

signed= ...?

-128-127

What determines the program order of execution of code?

data flow

Types of charts: strip, scope, sweep, step

1. strip= shows running data continuously scrolling from left to right 2. scope= points plotted until end of xscale reached, then plot clears, and plot begins at far left again 3. sweep= red line that indicates front ege of new data being plotted over old data 4. step= scope and sweep display plots faster than strip

how many bytes in header of each dimension?

4 bytes (think of visual)

How many bits in boolean?

8 bits

U8= bits/bytes?

8 bits or 1 byte

What maintains history of past data?

CHARTS, good for inside loop to see full set of data

What displays most recent array of values?

GRAPHS, good for outside loops to see full set of data

Error cluster does not include...?

VI name

Are "latches" guaranteed to be read by labVIEW?

Yes, at least once

each rectangle on connector pane represents...

a terminal

network-published shared variable

across an ethernet network, implemented using a project library in a project

What is so special about xy graph?!

allows you to plot any set of points evenly distributed or not

probe tool

allows you to see value into wire

formula node

allows you to use text to execute a function and mathematical formulas

what do rings use?

any numeric representation

Arrays vs. clusters

arrays have same data types, clusters can have different data types

event strtucture

labVIEW's programmatic tool for handling events

What does not conform to dataflow programming paradigm?

local variables

what does not conform to data flow programming paradigm?

local variables

icon/connector

means of connecting a vi to other vis

What is the easiest way to enforce dataflow?

modify subvi to have error clusters that can be used

single-process shared variable

multiple vis, implemented using a project library in a project

functional global

multiple vis, implented using a while loop with an uninitialized shift register to store global data

global variable

multiple vis, tied to a special global vi that has front panel but no block diagram

can a flat sequence structure be stopped once it begins?

no

can a subvi be edited from a functions palette?

no

Race condition

no control over how everything is executing - ex: write a, write b, write c --> resource --> write a, b, or c? (will the readers read a, b, or c?) or write a---> resource --> read, read, read (all writers read value A)

Are sequence structures encouraged?

no silly

does a block diagram execute left to right?

no??

Parallel loop running at different rates and 1+ loop is dependent on on another. what do you use?

notifier or queue

What is the default timeout value of an event structure?

notify and filter events - notify: event happened, get values from event, GREEN arrow, left side - filter: event is about to happen, able to change what happens, RED arrow with ?, right side -1 (never times out)

notify events vs. filter events

notify events (green arrow)- user action has already occurred filter events (red arrow)- user performed action but event is not processed, allows you to customize event handling

Random number function

number between 0 and 1

how are dimensions of an array defined?

number of indexes (so 2 index= 2D)

BLUE means

numeric

Know difference between graphs and charts

one maintains history, one displays recent values

DBL=

only one that can list non-integer numbers

what do enums use?

only unsigned integers?

property vs. invoke nodes

property= read and write properties of an object; explicitly or implicitly linked invoke= control state or actions of VI, used to perform actions on referenced items

concatenate

put in order

feedback node functions like...

shift register

What saves data?

shift registers, local variables

what should a sequence structure be replaced with?

state machine

best choice for case structure?

state machine? double check

Semaphores

stoplights do NOT transfer data

software control timing

timing (pauses, waits, time checks) you put in place to make code execute after a certain amount of time

property nodes execute from..

top to bottom ex: if an error occurs on 3 of 5 terminals, last two do not execute

Producer/consumer design

two parallel loops with queue buttons

what is a master/slave?

type of producer/consumer design - uses notifiers to allows loops to run at different rates

where is index of an array displayed?

upper left corner of array

control references

used for property and invoke nodes

conditional disable structure

used to define conditions that indicate which code on the block diagram executes

Wait (ms) icon

wait until next multiple icon (metronome symbol)

how do you update an indicator?

wire it directly to indicator terminal

What is the best way to transfer data?

wires

Do strings take up a lot of space?

yes lol