Glossary of LabVIEW terms

This is a glossary of LabVIEW terminology.

A

absolute path

File or directory path that describes the location relative to the top level of the file system.

active cell

Cell of a listbox, table, digital data, or tree control to which you can apply property changes.

active window

Window that is currently set to accept user input, usually the frontmost window. The title bar of an active window is highlighted. Make a window active by clicking it or by selecting it from the Windows menu.

ancestor class

Any LabVIEW class that is the parent, grandparent, and so on, of another LabVIEW class. The LabVIEW Object may be the ultimate ancestor.

application

Application created using the LabVIEW Development System and executed in the LabVIEW Run-Time System environment.

application instance

Instance of LabVIEW created for each target you create in a LabVIEW project. When you open a VI from the Project Explorer window, the VI opens in the application instance for the target. There is a separate instance of LabVIEW running for each target you create. LabVIEW also creates a main application instance, which contains open VIs that are not part of a project and VIs that you did not open from a project. See also target.

Application Programming Interface (API)

Programming interface for controlling software packages.

application reference

A reference to a VI Server, which can operate on the local machine or somewhere on the (global) network.

application zone

Memory allocation section that holds all data in a VI except execution data.

array

Ordered, indexed list of data elements of the same type.

array shell

Front panel object that houses an array. An array shell consists of an index display, a data object window, and an optional label. It can accept various data types.

artificial data dependency

Condition in a dataflow programming language in which the arrival of data, rather than its value, triggers execution of a node.

asynchronous execution

Mode in which multiple processes share processor time. For example, one process executes while others wait for interrupts during device I/O or while waiting for a clock tick.

Auto-indexing

Capability of loop structures to disassemble and assemble arrays at their borders. As an array enters a loop with auto-indexing enabled, the loop automatically disassembles it extracting scalars from 1D arrays, 1D arrays extracted from 2D arrays, and so on. Loops assemble data values into arrays as data values exit the loop in the reverse order.

automatic error handling

Setting in on VIs where LabVIEW automatically handles any error when a VI runs by suspending execution, highlighting the subVI or function where the error occurred, and displaying an error dialog box.

autoscaling

Ability of scales to adjust to the range of plotted values. On graph scales, autoscaling determines maximum and minimum scale values.

autosizing

Automatic resizing of labels to accommodate text you enter.

B

bit array tag

Multibit value representation of a connection to a real-world I/O point or memory variable. In LabVIEW, this type of tag can be comprised of up to 32 discrete values.

BNF

Backus-Naur Form. A common representation for language grammars in computer science.

Boolean controls and indicators

Front panel objects to manipulate and display Boolean (TRUE or FALSE) data.

Block Diagram

Pictorial description or representation of a program or algorithm. The block diagram consists of executable icons called nodes and wires that carry data between the nodes. The block diagram is the source code for the VI. The block diagram resides in the block diagram window of the VI.

breakpoint

Pause in execution used for debugging.

Breakpoint tool

Tool to set a breakpoint on a VI, node, or wire.

broken arrow

See broken Run button below.

broken Run button

Button that replaces the Run button when a VI cannot run because of errors.

broken VI

VI that cannot run because of errors; signified by a broken arrow in the broken Run button.

buffer

Temporary storage for acquired or generated data.

Build Process

An automated process to turn source into an export.

Build Process Export

A versioned proxy of source in one of many forms. Example: executable, NI Package, VI Package, PPL, DLL, etc

Bundle function

Function that creates clusters from various types of elements.

byte stream file

File that stores data as a sequence of ASCII characters or bytes.

C

C string (CStr)

A series of zero or more unsigned characters, terminated by a zero, used in the C programming language.

caption label

Label on a front panel object used to name the object in the user interface. You can translate this label to other languages without affecting the block diagram source code. See also Name Label.

case

One subdiagram of a Case structure.

Case structure

Conditional branching control structure that executes one of its subdiagrams based on the input to the Case structure. It is the combination of the IF, THEN, ELSE, and CASE statements in control flow languages.

cast

To change the type descriptor of a data element without altering the memory image of the data.

chart

2D display of one or more plots in which the display retains a history of previous data, up to a maximum that you define. The chart receives the data and updates the display point by point or array by array, retaining a certain number of past points in a buffer for display purposes.

See also: scope chart, strip chart, and sweep chart.

checkbox

Small square box in a dialog box you can select or clear. Checkboxes generally are associated with multiple options that you can set. You can select more than one checkbox.

child class

A LabVIEW class that inherits data and member VIs from an ancestor LabVIEW class.

CIN

Code Interface Node (CIN). Special block diagram node through which you can link text-based code to a VI.

CIN source code

Original, uncompiled text code.

See also: object code and Code Interface Node (CIN).

class

A category containing properties, methods, and events. Classes are arranged in a hierarchy with each class inheriting the properties and methods associated with the class in the preceding level.

class library

The group of VIs that define a LabVIEW class. The class library also stores the data of the LabVIEW class.

cloning

To make a copy of a control or another object by clicking it while pressing the <Ctrl> key and dragging the copy to its new location.

Cluster

A set of ordered, unindexed data elements of any data type, including numeric, Boolean, string, array, or cluster. The elements must be all controls or all indicators.

cluster shell

Front panel object that contains the elements of a cluster.

code resource

Resource containing executable machine code. You link code resources to LabVIEW through a CIN.

coercion

Automatic conversion LabVIEW performs to change the numeric representation of a data element.

coercion dot

Appears on a block diagram node to alert you that you have wired data of two different numeric data types together. Also appears when you wire any data type to a variant data type, or when LabVIEW discards bits of a fixed-point number.

Coloring tool

Tool to set foreground and background colors.

compile

Process that converts high-level code to machine-executable code. LabVIEW compiles VIs automatically before they run for the first time after you create or edit alteration.

concatenated Pascal string (CPStr)

A list of Pascal-type strings concatenated into a single block of memory.

conditional terminal

Terminal of a While Loop that contains a Boolean value that determines if the VI performs another iteration. A conditional terminal also can be added to a For Loop to stop execution early when a condition occurs.

connector

Part of the VI or function node that contains input and output terminals. Data values pass to and from the node through a connector.

connector pane

Region in the upper right corner of a front panel or block diagram window that displays the VI terminal pattern. It defines the inputs and outputs you can wire to a VI.

constant

A terminal on the block diagram that supplies fixed data values to the block diagram.

See also: universal constant and user-defined constant.

content rectangle

Region of a listbox, table, digital data, or tree control that contains all headers and cells. The content rectangle does not include scroll bars.

Context Help window

Window that displays basic information about LabVIEW objects when you move the cursor over each object. Objects with context help information include VIs, functions, constants, structures, palettes, properties, methods, events, dialog box components, and items in the [Project Explorer] window.

continuous run

Execution mode in which a VI runs repeatedly until the operator stops it. Click the Continuous Run button to run a VI repeatedly.

Continuous Run button

Icon that indicates a VI is set to execute repeatedly until the user stops it.

contour plot

Plot where contour lines are used to connect points of equal value.

control

Front panel object for entering data to a VI interactively or to a subVI programmatically, such as a knob, push button, or dial.

control flow

Programming system in which the sequential order of instructions determines execution order. Most text-based programming languages are control flow languages.

Controls palette

Palette that contains front panel controls, indicators, and decorative objects.

conversion

Changing the type of a data element.

UTC

Coordinated Universal Time. Time scale that is determined using highly precise atomic clocks. LabVIEW uses UTC as the standard for the internal representation of dates and times.

count terminal

Terminal of a For Loop whose value determines the number of times the For Loop executes its subdiagram.

current VI

VI whose front panel, block diagram, or Icon Editor is the active window.

D

data dependency

Condition in a dataflow programming language in which a node cannot execute until it receives data from another node.

See also: artificial data dependency

data flow

Programming system involving the creation of block diagrams having executable nodes connected by wires, where the wires between nodes indicate that data produced by one node is used by another node. Nodes may execute when they have received all necessary input data and may produce output data to other nodes in the diagram. G is a dataflow system.

data storage formats

Arrangement and representation of data stored in memory.

data type

Format for information. In LabVIEW, acceptable data types for most VIs and functions are numeric, array, string, Boolean, path, refnum, enumerated type, waveform, and cluster.

data type descriptor

Code that identifies data types; used in data storage and representation.

datalog file

File that stores data as a sequence of records of a single, arbitrary data type that you specify when you create the file. Although all the records in a datalog file must be a single type, that type can be complex. For example, you can specify that each record is a cluster that contains a string, a number, and an array.

default

Preset value. Many VI inputs use a default value if you do not specify a value.

default input

Default value of a front panel control.

deploy

To download items or apply settings to a target in the Project Explorer window.

descendant class

A child, grandchild, and so on, of another LabVIEW class.

dialog box

Window that appears when an application needs further information to carry out a command.

dimension

Size and structure of an array.

directory

Structure for organizing files into convenient groups. A directory is like an address that shows the location of files. A directory can contain files or subdirectories of files.

DLL

Dynamic Link Library

drag

To use the cursor on the screen to select, move, copy, or delete objects.

drive

Letter in the range a-z followed by a colon ":", to indicate a logical disk drive.

driver

Software that controls a specific hardware device, such as a DAQ device.

DTbl

Digital table.

DWDT

Digital waveform data type.

dynamic data type

Data type used by Express VIs that includes the data associated with a signal and attributes that provide information about the signal, such as the name of the signal or the date and time the data was acquired. Attributes specify how the signal appears on a graph or chart.

dynamic dispatch

A VI that defines a method of a LabVIEW class. Dynamic dispatch member VIs are VIs with the same name that occur throughout the class hierarchy. Similar to polymorphic VIs, LabVIEW determines at run time which member VI to call.

E

edit mode

When you can make changes to a VI.

empty array

Array that has zero elements but has a defined data type. For example, an array that has a numeric control in its data display window but has no defined values for any element is an empty numeric array.

encapsulation

The consolidation of data and methods into a LabVIEW class, where the data is accessible only through class member VIs.

end of file (EOF)

Character offset of the end of file relative to the beginning of the file. The EOF is the size of the file.

Error cluster

Consists of a Boolean status indicator, a numeric code indicator, and a string source indicator.

error in

Error cluster that enters a VI.

Error List window

Window that displays errors and warnings occurring in a VI and in some cases recommends how to correct the errors.

error message

Indication of a software or hardware malfunction or of an unacceptable data entry attempt.

error out

The error cluster that leaves a VI.

Event Data Node

Node attached to the left and right sides of an Event structure indicating the available data for the event you configured that case to handle. If you configure a single case to handle multiple events, only the data that is common to all handled event types is available.

event driven programming

Method of programming whereby the program waits on an event to occur before executing one or more functions.

execution highlighting

Debugging technique that animates VI execution to illustrate the data flow in the VI.

Express VI

A subVI designed to aid in common measurement tasks. You configure an Express VI using a configuration dialog box.

F

FIFO

First-in-first-out memory buffer. The first data stored is the first data sent to the acceptor.

file refnum

Reference number. An identifier that LabVIEW uses as reference to a file object. Use a file refnum as an input parameter for certain file IO functions.

filter events

Allow control over how the user interface behaves.

Flat Sequence structure

Program control structure that executes its subdiagrams in numeric order. Use this structure to force nodes that are not data dependent to execute in the order you want if flow-through parameters are not available. The Flat Sequence structure displays all the frames at once and executes the frames from left to right until the last frame executes.

flattened data

Data of any type that has been converted to a string, usually for writing the data to a file.

flattened pixmap

The flattened pixmap is a structure used to load and save images to and from disk.

For Loop

Iterative loop structure that executes its subdiagram a set number of times with the option of stopping execution early when a condition occurs. Equivalent to text-based code: For i = 0 to n — 1, do...

Formula node

Node that executes equations you enter as text. Especially useful for lengthy equations too cumbersome to build in block diagram form.

frame

Subdiagram of a Flat or Stacked Sequence structure.

free label

Label on the front panel or block diagram that does not belong to any other object.

front panel

Interactive user interface of a VI. Front panel appearance imitates physical instruments, such as oscilloscopes and multimeters.

function

Built-in execution element, comparable to an operator, function, or statement in a text-based programming language.

Functions palette

Palette that contains VIs, functions, block diagram structures, and constants.

G

G

Graphical programming language LabVIEW uses.

Get Color tool

Copies colors for pasting with the Coloring tool.

global variable

Accesses and passes data among several VIs on a block diagram.

glyph

Small picture or icon.

graph

2D display of one or more plots. A graph receives and plots data as a block.

H

handle

Pointer to a pointer to a block of memory that manages reference arrays and strings. An array of strings is a handle to a block of memory that contains handles to strings.

hex

Hexadecimal. Base-16 number system.

Hierarchy window

Window that graphically displays the hierarchy of VIs and subVIs.

See also: VI Hierarchy window

housing

Non-moving part of front panel controls and indicators that contains sliders, scales, or scroll boxes.

I

IAC

Interapplication communication.

icon

Graphical representation of a node on a block diagram.

Icon editor

Interface similar to that of a graphics program for creating VI icons.

indicator

Front panel object that displays output, such as a graph or LED.

Inf

Digital display value for a floating-point representation of infinity.

inheritance

The use of one LabVIEW class as the initial definition of a new LabVIEW class. The inheriting class has the same data and member VIs as the ancestor class initially, but you can modify or add to the existing data and methods as you need.

initializer terminal

Terminal that sets the initial value of a Feedback Node.

inplace

The condition in which two or more terminals, such as error I/O terminals or shift registers, use the same memory space.

instrument driver

A set of high-level functions that control and communicate with instrument hardware in a system.

integer

Any of the natural numbers, their negatives, or zero.

integer word length

The number of integer bits in a binary number, or, given an initial position to the left or right of the most significant bit, the number of bits to shift the binary point to reach the most significant bit. If the integer word length is positive, shift the binary point to the left. If the integer word length is negative, shift the binary point to the right.

intensity map/plot

Method of displaying three dimensions of data in a 2D plot with the use of color.

IP

Internet protocol.

iteration terminal

Terminal of a For Loop or While Loop that contains the current number of completed iterations.

IVI

Interchangeable Virtual Instruments. A software standard for creating a common interface (API) to common test and measurement instruments.

IVI driver

A driver written according to the IVI specification. The generic driver for a class of instruments (such as voltmeters) is called a class driver, whereas the driver for a specific instrument from a specific manufacturer is called a device-specific driver.

K

Kwords

1,024 words (16 bits) of memory.

L

label

Text object used to name or describe objects or regions on the front panel or block diagram.

Labeling tool

Tool to create labels and enter text into text windows.

LabVIEW

Laboratory Virtual Instrument Engineering Workbench. LabVIEW is a graphical programming language that uses icons instead of lines of text to create programs.

LabVIEW class

A user-defined data type in LabVIEW. A LabVIEW class defines the data and methods associated with an object of the class.

LabVIEW class hierarchy

The inheritance relationship of LabVIEW classes.

LabVIEW Object

The root of the LabVIEW class inheritance tree.

LabVIEW string (LStr)

The string data type that LabVIEW block diagrams use.

LabVIEW system time

The date and time that LabVIEW uses as a reference for absolute time. LabVIEW system time is defined as 12:00 a.m., Friday, January 1, 1904, Universal Time.

See also: Coordinated Universal Time (UTC).

legend

Object a graph or chart owns to display the names and plot styles of plots on that graph or chart.

library

See also: LLB and project library

listbox

Box within a dialog box that lists all available choices for a command. For example, a list of filenames on a disk.

LLB

LabVIEW file that contains a collection of related VIs for a specific use.

local variable

Variable that enables you to read or write to one of the controls or indicators on the front panel of a VI.

LSB

Least Significant Bit.

M

marquee

Moving, dashed border that surrounds selected objects.

MB

Megabytes of memory. 1 MB is equal to 1,024 KB.

member VI

A VI that a LabVIEW class owns. A member VI can access the private data of a LabVIEW class.

memory buffer

See also: buffer

menu bar

Horizontal bar that lists the names of the main menus of an application. The menu bar appears below the title bar of a window. Each application has a menu bar that is distinct for that application, although some menus and commands are common to many applications.

method

A procedure that is executed when an object receives a message. A method is always associated with a class.

MSB

Most Significant Bit.

multicore programming

Two or more processors in one computer, each of which can simultaneously run a separate thread.

multithreaded application

Application that runs several different threads of execution independently. On a multiple processor computer, the different threads might be running on different processors simultaneously.

multithreading

A technique for an operating system to handle multiple small tasks at one time, known as threads.

N

Name Label

Label of a front panel object used to name the object and as distinguish it from other objects. The label also appears on the block diagram terminal, local variables, and property nodes that are part of the object.

See also: caption label.

NaN

Digital display value for a floating-point representation of <Not A Number>. Typically the result of an undefined operation, such as log(–1).

NI-PSP

NI Publish-Subscribe Protocol. A data transfer protocol to write and allow users to read live data. NI-PSP is a proprietary technology that provides fast and reliable data transmission for large and small applications and is installed as a service on the computer when you install LabVIEW.

node

Program execution element. Nodes are analogous to statements, operators, functions, and subroutines in text-based programming languages. On a block diagram, nodes include functions, structures, and subVIs.

non-displayable characters

ASCII characters that cannot be displayed, such as null, backspace, tab, and so on.

not-a-refnum

Predefined value that indicates the refnum is invalid.

notify events

Tell LabVIEW that a user action has already occurred, such as when a user changes the value of a control.

numeric controls and indicators

Front panel objects to manipulate and display numeric data.

O

object

Generic term for any item on the front panel or block diagram, including controls, indicators, nodes, wires, and imported pictures.

object code

Compiled version of source code. Object code is not standalone because you must load it into LabVIEW to run it.

Object Shortcut Menu tool

Tool to access a shortcut menu for an object.

OLE

Object Linking and Embedding.

OLE for Process Control (OPC)

OLE for Process Control. A set of standard interfaces developed by the OPC Foundation to ensure interoperability among control devices from different manufacturers for the transfer of real-time plant data.

one-dimensional

Having one dimension, as in the case of an array that has only one row of elements.

Operating tool

Tool to enter data into controls or to operate them.

override VI

Allows you to override an member VI of an ancestor LabVIEW class.

owning pane

The pane of the front panel in which an object resides.

P

palette

Displays objects or tools you can use to build the front panel or block diagram.

panel window

VI window that contains the front panel, the toolbar, and the icon and connector panes.

parent class

An existing LabVIEW class from which another class inherits.

parser

VI that scans a string to determine the function of each of the elements in the string.

Pascal string (PStr)

A series of unsigned characters, with the value of the first character indicating the length of the string. Used in the Pascal programming language.

picture

Series of graphics instructions that a picture indicator uses to create a picture.

picture indicator

General-purpose indicator for displaying pictures that can contain lines, circles, text, and other types of graphic shapes.

pixel

Smallest unit of a digitized picture.

pixmap

Standard format for storing pictures in which a color value represents each pixel. A bitmap is a black and white version of a pixmap.

See also: flattened pixmap

plot

Graphical representation of an array of data shown either on a graph or a chart.

point

Cluster that contains two 16-bit integers that represent horizontal and vertical coordinates.

polymorphism

Ability of a node to automatically adjust to data of different representation, type, or structure.

Positioning tool

Tool to move and resize objects.

private data

The data of a LabVIEW class. Only member VIs of a class can access the private data of a class.

private data control

Defines the data of the LabVIEW class.

private scope

Only VIs within the same LabVIEW class can call the member VI. Private member VIs display a red key glyph in the Project Explorer window.

probe

Debugging feature for checking intermediate values in a VI.

Probe tool

Tool to create probes on wires.

project

A collection of LabVIEW files and non-LabVIEW files that you can use to create build specifications and deploy or download files to targets.

Project Explorer window

Window in which you can create and edit LabVIEW projects.

project library

A collection of VIs, type definitions, shared variables, palette menu files, and other files, including other project libraries.

Properties dialog boxes

Dialog boxes accessed from the shortcut menu of a control or indicator that you can use to configure how the control or indicator appears in the front panel window.

Property Node

Sets or finds the properties of a VI or application.

protected scope

Only VIs within the same LabVIEW class or a descendant class can call the member VI. Protected member VIs display a dark yellow key glyph in the Project Explorer window.

prototype

Simple, quick implementation of a particular task to demonstrate that the design has the potential to work. The prototype usually has missing features and might have design flaws. In general, prototypes should be thrown away, and the feature should be reimplemented for the final version.

pseudocode

Simplified language-independent representation of programming code.

public scope

Any VI can call the member VI of the LabVIEW class as a subVI.

pull-down menus

Menus accessed from a menu bar. Pull-down menu items are usually general in nature.

R

race condition

Occurs when two or more pieces of code that execute in parallel change the value of the same shared resource, typically a global or local variable.

real-time

Pertaining to the performance of a computation during the actual time that the related physical process transpires so results of the computation can be used in guiding the physical process.

rectangle

Cluster that contains four 16-bit integers. The first two values describe the vertical and horizontal coordinates of the top left corner. The last two values describe the vertical and horizontal coordinates of the bottom right corner.

recursion

The ability of a VI to call itself on its own block diagram including the block diagram of any subVIs. Use recursion to operate many times on the output of the same process.

reentrant execution

Mode in which calls to multiple instances of a subVI can execute in parallel with distinct and separate data storage.

refnum

Reference number. An identifier that LabVIEW uses as reference to an object such as a VI, application, or an ActiveX or .NET object. Use a refnum as an input parameter for a function or VI to perform an operation on the object.

relative coordinates

Picture coordinates relative to the current location of the pen.

representation

Subtype of the numeric data type, of which there are 8-, 16-, 32-, and 64-bit signed and unsigned integers, as well as single-, double-, fixed-point, and extended-precision, floating-point numbers.

resizing circles or handles

Circles or handles that appear on the borders of an object to indicate the points where you can resize the object.

ring control

Special numeric control that associates 32-bit integers, starting at 0 and increasing sequentially, with a series of text labels or graphics.

row-major order

Way to organize the data in a 2D array by rows.

run mode

When a VI is running or reserved to run. A VI enters run mode when you click the Run or Run Continuously buttons on the front panel toolbar, the single-stepping buttons on the block diagram toolbar, or select Operate»Change to Run Mode. In run mode, all front panel objects have an abridged set of shortcut menu items. You cannot edit a VI while the VI runs.

S

scalar

Number that a point on a scale can represent. A single value as opposed to an array. Scalar Boolean values and clusters are explicitly singular instances of their respective data types.

scale

Part of graph, chart, and some numeric controls and indicators that contains a series of marks or points at known intervals to denote units of measure.

scope chart

Numeric indicator modeled on the operation of an oscilloscope.

Scrolling tool

Tool to move through windows.

sequence local

Terminal to pass data between the frames of a Stacked Sequence structure.

sequence structure

Template:See a;so.

shared library

A file containing executable program modules that any number of different programs can use to perform some function. Shared libraries are useful when you want to share the functionality of the VIs you build with other developers.

shared variable

Variable that enables you to read or write live data among several VIs in a project or across a network.

shift register

Optional mechanism in loop structures to pass the value of a variable from one iteration of a loop to a subsequent iteration. Shift registers are similar to static variables in text-based programming languages.

shortcut menu

Menu accessed by right-clicking an object. Menu items pertain to that object specifically.

sibling class

Any LabVIEW class that has the same parent class.

slider

Moveable part of slide controls and indicators.

software configuration management (SCM)

Mechanism for controlling changes to source code, documents, and other material that make up a product. During software development, source code control is a form of configuration management. Changes occur only through the source code control mechanism. It is also common to implement release configuration management to ensure you can rebuild a particular release of software, if necessary. Configuration management implies archival development of tools, source code, and so on.

source control

A solution to the problem of sharing VIs and controlling access to avoid accidental loss of data. You can use a source control provider to share files among multiple users, improve security and quality, and track changes to shared projects. Also called source code control.

Software Module

A body of code designed to accomplish a specific task or model a specific idea. A software module uses other software modules by specifying dependencies on exports. Applications can be created by assembling software modules.

source lines of code (SLOC)

Measure of the number of lines of code that make up a text-based project. It is used in some organizations to measure the complexity and cost of a project. How the lines are counted depends on the organization. For example, some organizations do not count blank lines and comment lines. Some count C lines, and some count only the final assembly language lines.

Stacked Sequence structure

Program control structure that executes its subdiagrams in numeric order. Use this structure to force nodes that are not data dependent to execute in the order you want if flow-through parameters are not available. The Stacked Sequence structure displays each frame so you see only one frame at a time and executes the frames in order until the last frame executes.

static dispatch

A method of a LabVIEW class. You define a static dispatch member VI in only one level of the LabVIEW class hierarchy.

string

Representation of a value as text.

string controls and indicators

Front panel objects to manipulate and display text.

strip chart

Numeric plotting indicator modeled after a paper strip chart recorder, which scrolls as it plots data.

structure

Program control element, such as a Flat Sequence structure, Stacked Sequence structure, Case structure, For Loop, or While Loop.

subdiagram

Block diagram within the border of a structure.

subpalette

Palette that you access from another palette that is above the subpalette in the hierarchy.

subVI

VI used on the block diagram of another VI. Comparable to a subroutine.

sweep chart

Numeric indicator modeled on the operation of an oscilloscope. It is similar to a scope chart, except that a line sweeps across the display to separate old data from new data.

syntax

Set of rules to which statements must conform in a particular programming language.

T

target

A device or machine on which a VI runs. You must use a LabVIEW project to work with an RT, FPGA, or PDA target.

template VI

VI that contains common controls and indicators from which you can build multiple VIs that perform similar functions. Access template VIs from the New dialog box.

terminal

Object or region on a node through which data values pass.

time stamp

A data type for storing absolute time with high precision..

time step

Interval from t to t + dt.

tip strip

Small yellow text banners that identify the terminal name and make it easier to identify terminals for wiring.

tool

Special cursor to perform specific operations.

toolbar

Bar that contains command buttons to run and debug VIs.

Tools palette

Palette that contains tools you can use to edit and debug front panel and block diagram objects.

top-level VI

VI at the top of the VI hierarchy. This term distinguishes the VI from its subVIs.

tunnel

Data entry or exit terminal on a structure.

two-dimensional

Having two dimensions, as in the case of an array that has several rows and columns.

type definition

Master copy of a custom object that several VIs can use.

type descriptor

Code that identifies data types; used in data storage and representation.

See also: data type descriptor

U

universal constant

Block diagram object you cannot edit that emits a particular ASCII character or standard numeric constant, for example, π.

user

Person who initiates and monitors the operation of a process.

See also: operator

user-defined constant

Block diagram object that emits a value you set.

V

variant data

Variant data do not conform to a specific data type and they contain attributes, such as channel names and channel units. LabVIEW represents variant data with the variant data type.

vector

1D array.

VI

See also: virtual instrument (VI)

virtual instrument (VI)

Program in LabVIEW that models the appearance and function of a physical instrument.

W

waveform

Multiple voltage readings taken at a specific sampling rate.

waveform chart

Indicator that plots data points at a certain rate.

WDT

Waveform data type.

While Loop

Loop structure that repeats a section of code until a condition occurs.

wire

Data path between nodes.

wire bend

Point where two wire segments join.

wire branch

Section of wire that contains all the wire segments from junction to junction, terminal to junction, or terminal to terminal if there are no junctions between.

wire junction

Point where three or more wire segments join.

wire segment

Single horizontal or vertical piece of wire.

wire stubs

Truncated wires that appear next to unwired terminals when you move the Wiring tool over a VI or function node.

Wiring tool

Tool to define data paths between terminals.

wizard

A dialog box with a sequence of pages through which you can move forward and backward as you fill in information.

word length

The total number of bits a system uses to store a particular piece of data, such as a number. LabVIEW accepts a maximum word length of 64 bits.

X

XControl

A front panel object with dedicated UI logic code.

XNode

A block diagram object with dedicated code generation logic.