The latest versions of LabVIEW are LabVIEW 2023 Q1 (released in April 2023) and LabVIEW NXG 5.1 (released in January 2021).[3] NI released the free for non-commercial use LabVIEW and LabVIEW NXG Community editions on April 28, 2020.[4]
Dataflow programming
The programming paradigm used in LabVIEW, sometimes called G, is based on data availability. If there is enough data available to a subVI or function, that subVI or function will execute. The execution flow is determined by the structure of a graphical block diagram (the LabVIEW-source code) on which the programmer connects different function-nodes by drawing wires. These wires propagate variables, and any node can execute as soon as all its input data become available. Since this might be the case for multiple nodes simultaneously, LabVIEW can execute inherently in parallel.[5]: 1–2 Multi-processing and multi-threading hardware is exploited automatically by the built-in scheduler, which multiplexes multiple OS threads over the nodes ready for execution.
Graphical programming
LabVIEW integrates the creation of user interfaces (termed front panels) into the development cycle. LabVIEW programs-subroutines are termed virtual instruments (VIs). Each VI has three components: a block diagram, a front panel, and a connector pane. The last is used to represent the VI in the block diagrams of others, calling VIs. The front panel is built using controls and indicators. Controls are inputs: they allow a user to supply information to the VI. Indicators are outputs: they indicate, or display, the results based on the inputs given to the VI. The back panel, which is a block diagram, contains the graphical source code. All of the objects placed on the front panel will appear on the back panel as terminals. The back panel also contains structures and functions which perform operations on controls and supply data to indicators. The structures and functions are found on the Functions palette and can be placed on the back panel. Collectively controls, indicators, structures, and functions are referred to as nodes. Nodes are connected using wires, e.g., two controls and an indicator can be wired to the addition function so that the indicator displays the sum of the two controls. Thus a virtual instrument can be run as either a program, with the front panel serving as a user interface, or, when dropped as a node onto the block diagram, the front panel defines the inputs and outputs for the node through the connector pane. This implies each VI can be easily tested before being embedded as a subroutine into a larger program.
The graphical approach also allows nonprogrammers to build programs by dragging and dropping virtual representations of lab equipment with which they are already familiar. The LabVIEW programming environment, with the included examples and documentation, makes it simple to create small applications. This is a benefit on one side, but there is also a certain danger of underestimating the expertise needed for high-quality G programming. For complex algorithms or large-scale code, a programmer must possess extensive knowledge of the special LabVIEW syntax and the topology of its memory management. The most advanced LabVIEW development systems offer the ability to build stand-alone applications. Furthermore, it is possible to create distributed applications, which communicate by a client–server model, and are thus easier to implement due to the inherently parallel nature of G.
Widely-accepted design patterns
Applications in LabVIEW are usually designed using well-known architectures,[citation needed] known as design patterns. The most common design patterns for graphical LabVIEW applications are listed in the table below.
Common design patterns for LabVIEW applications
Design pattern
Purpose
Implementation details
Use cases
Limitations
Functional Global Variable
Exchange information without using global variables
A shift register of a while loop is used to store the data and the while loop runs only one iteration in a "non-reentrant" virtual instrument (VI)
Exchange information with less wiring
All owning virtual instruments (VIs) are kept in memory.
Case structure inside a while loop pass an enumerated variable to a shift register, representing the next state; complex state machines can be designed using the Statechart module
• User interfaces • Complex logic • Communication protocols
All possible states must be known in advance.
Event-driven user interface
Lossless processing of user actions
GUI events are captured by an event structure queue, inside a while loop; the while loop is suspended by the event structure and resumes only when the desired events are captured
A master loop controls the execution of two slave loops, that communicate using notifiers, queues and semaphores; data-independent loops are automatically executed in separate threads
Data sampling and visualization
Order of execution is not obvious to control.
Queued state machine with event-driven producer-consumer
Highly responsive user-interface for multithreaded applications
An event-driven user interface is placed inside the producer loop and a state machine is placed inside the consumer loop, communicating using queues between themselves and other parallel VIs
LabVIEW includes extensive support for interfacing to devices such as instruments, cameras, and other devices. Users interface to hardware by either writing direct bus commands (USB, GPIB, Serial) or using high-level, device-specific drivers that provide native LabVIEW function nodes for controlling the device.
LabVIEW includes built-in support for NI hardware platforms such as CompactDAQ and CompactRIO, with a large number of device-specific blocks for such hardware, the Measurement and Automation eXplorer (MAX) and Virtual Instrument Software Architecture (VISA) toolsets.
National Instruments makes thousands of device drivers available for download on the NI Instrument Driver Network (IDNet).[9]
Code compiling
LabVIEW includes a compiler that produces native code for the CPU platform. The graphical code is converted into Dataflow Intermediate Representation, and then translated into chunks of executable machine code by a compiler based on LLVM. Run-time engine calls these chunks, allowing better performance. The LabVIEW syntax is strictly enforced during the editing process and compiled into the executable machine code when requested to run or upon saving. In the latter case, the executable and the source code are merged into a single binary file. The execution is controlled by LabVIEW run-time engine, which contains some pre-compiled code to perform common tasks that are defined by the G language. The run-time engine governs execution flow, and provides a consistent interface to various operating systems, graphic systems and hardware components. The use of run-time environment makes the source code files portable across supported platforms. LabVIEW programs are slower than equivalent compiled C code, though like in other languages, program optimization often allows to mitigate issues with execution speed.[10]
Large libraries
Many libraries with a large number of functions for data acquisition, signal generation, mathematics, statistics, signal conditioning, analysis, etc., along with numerous for functions such as integration, filters, and other specialized abilities usually associated with data capture from hardware sensors is enormous. In addition, LabVIEW includes a text-based programming component named MathScript with added functions for signal processing, analysis, and mathematics. MathScript can be integrated with graphical programming using script nodes and uses a syntax that is compatible generally with MATLAB.[11]
Parallel programming
LabVIEW is an inherently concurrent language, so it is very easy to program multiple tasks that are performed in parallel via multithreading. For example, this is done easily by drawing two or more parallel while loops and connecting them to two separate nodes. This is a great benefit for test system automation, where it is common practice to run processes like test sequencing, data recording, and hardware interfacing in parallel.
Ecosystem
Due to the longevity and popularity of the LabVIEW language, and the ability for users to extend its functions, a large ecosystem of third party add-ons has developed via contributions from the community. Most of these add-ons are available for direct download and installation into LabVIEW using VI Package Manager (VIPM),[12] the official package manager for LabVIEW add-ons. National Instruments also hosts a marketplace for both free and paid LabVIEW add-ons called the NI Tools Network.
User community
There is a low-cost LabVIEW Student Edition aimed at educational institutions for learning purposes. There is also an active community of LabVIEW users who communicate through several electronic mailing lists (email groups) and Internet forums.
National Instruments provides a free-for-non-commercial use version called LabVIEW Community Edition.[14] This version includes everything in the Professional Editions of LabVIEW, has no watermarks, and includes the LabVIEW NXG Web Module for non-commercial use. These editions may also be used by K-12 schools.[15]
Since G language is non-textual, software tools such as versioning, side-by-side (or diff) comparison, and version code change tracking cannot be applied in the same manner as for textual programming languages. There are some additional tools to make comparison and merging of code with source code control (versioning) tools such as subversion, CVS and Perforce.[16][17][18]
Release history
In 2005, starting with LabVIEW 8.0, major versions are released around the first week of August, to coincide with the annual National Instruments conference NI Week, and followed by a bug-fix release the following February.
In 2009, National Instruments began naming releases after the year in which they are released. A bug-fix is termed a Service Pack, for example, the 2009 service pack 1 was released in February 2010.
In 2017, National Instruments moved the annual conference to May and released LabVIEW 2017 alongside a completely redesigned LabVIEW NXG 1.0 built on Windows Presentation Foundation (WPF).
OpenG, as well as LAVA Code Repository (LAVAcr), serve as repositories for a wide range of Open Source LabVIEW applications and libraries. SourceForge has LabVIEW listed as one of the possible languages in which code can be written.
VI Package Manager has become the standard package manager for LabVIEW libraries. It is very similar in purpose to Ruby's RubyGems and Perl's CPAN, although it provides a graphical user interface similar to the Synaptic Package Manager. VI Package Manager provides access to a repository of the OpenG (and other) libraries for LabVIEW.
National Instruments also offers a product named Measurement Studio, which offers many of the test, measurement, and control abilities of LabVIEW, as a set of classes for use with MicrosoftVisual Studio. This allows developers to harness some of LabVIEW's strengths within the text-based .NET Framework. National Instruments also offers LabWindows/CVI as an alternative for ANSI C programmers.
When applications need sequencing, users often use LabVIEW with the TestStand test management software, also from National Instruments.
The Ch interpreter is a C/C++ interpreter that can be embedded in LabVIEW for scripting.[29]
DSP Robotics' FlowStone DSP also uses a form of graphical programming similar to LabVIEW but is limited to the robotics industry.
LabVIEW has a direct node with modeFRONTIER, a multidisciplinary and multi-objective optimization and design environment, written to allow coupling to almost any computer-aided engineering tool. Both can be part of the same process workflow description and can be virtually driven by the optimization technologies available in modeFRONTIER.
Bress, Thomas J. (2013). Effective LabVIEW Programming. [S.l.]: NTS Press. ISBN978-1-934891-08-7.
Blume, Peter A. (2007). The LabVIEW Style Book. Upper Saddle River, NJ: Prentice Hall. ISBN978-0-13-145835-2.
Travis, Jeffrey; Kring, Jim (2006). LabVIEW for Everyone : Graphical Programming Made Easy and Fun (3rd ed.). Upper Saddle River, NJ: Prentice Hall. ISBN0-13-185672-3.
Conway, Jon; Watts, Steve (2003). A Software Engineering Approach to LabVIEW. Upper Saddle River, NJ: Prentice Hall PTR. ISBN0-13-009365-3.
Olansen, Jon B.; Rosow, Eric (2002). Virtual Bio-Instrumentation : Biomedical, Clinical, and Healthcare Applications in LabVIEW. Upper Saddle River, NJ: Prentice Hall PTR. ISBN0-13-065216-4.
Beyon, Jeffrey Y. (2001). LabVIEW Programming, Data Acquisition and Analysis. Upper Saddle River, NJ: Prentice Hall PTR. ISBN0-13-030367-4.
Travis, Jeffrey (2000). Internet Applications In LabVIEW. Upper Saddle River, NJ: Prentice Hall PTR. ISBN0-13-014144-5.
Essick, John (1999). Advanced LabVIEW Labs. Upper Saddle River, NJ: Prentice Hall. ISBN0-13-833949-X.
Belletti A., Borromei R., Ingletto G., A.; Borromei, R.; Ingletto, G. (September 2006). "Teaching physical chemistry experiments with a computer simulation by LabVIEW". Journal of Chemical Education. 83 (9). ACS: 1353–1355. Bibcode:2006JChEd..83.1353B. doi:10.1021/ed083p1353.((cite journal)): CS1 maint: multiple names: authors list (link)
Lauterburg, Urs (June 2001). "LabVIEW in Physics Education"(PDF). A White Paper About Using LabVIEW in Physics Demonstration and Laboratory Experiments and Simulations.
Drew SM, Steven M. (December 1996). "Integration of National Instruments' LabVIEW software into the chemistry curriculum". Journal of Chemical Education. 73 (12). ACS: 1107–1111. Bibcode:1996JChEd..73.1107D. doi:10.1021/ed073p1107.
Muyskens MA, Glass SV, Wietsma TW, Gray TM, Mark A.; Glass, Samuel V.; Wietsma, Thomas W.; Gray, Terry M. (December 1996). "Data acquisition in the chemistry laboratory using LabVIEW software". Journal of Chemical Education. 73 (12). ACS: 1112–1114. Bibcode:1996JChEd..73.1112M. doi:10.1021/ed073p1112.((cite journal)): CS1 maint: multiple names: authors list (link)
Ogren PJ, Jones TP, Paul J.; Jones, Thomas P. (December 1996). "Laboratory interfacing using the LabVIEW software package". Journal of Chemical Education. 73 (12). ACS: 1115–1116. Bibcode:1996JChEd..73.1115O. doi:10.1021/ed073p1115.
