LabVIEW explained

LabVIEW
Developer:National Instruments
Latest Release Version:LabVIEW NXG 5.1
LabVIEW 2023 Q3
Operating System:Cross-platform

Windows, macOS, Linux

Genre:Data acquisition, instrument control, test automation, analysis and signal processing, industrial control, embedded system design
License:Proprietary
Programming Language:C, C++, C#

Laboratory Virtual Instrument Engineering Workbench (LabVIEW)[1] is a graphical system design and development platform produced and distributed by National Instruments, based on a programming environment that uses a visual programming language. It is widely used for data acquisition, instrument control, and industrial automation. It provides tools for designing and deploying complex test and measurement systems.

The visual (aka graphical) programming language is called "G" (not to be confused with G-code). It is a dataflow language originally developed by National Instruments.[2] LabVIEW is supported on a variety of operating systems (OSs), including macOS and other versions of Unix and Linux, as well as Microsoft Windows.

The latest versions of LabVIEW are LabVIEW 2023 Q1 (released in April 2023) and LabVIEW NXG 5.1 (released in January 2021).[3] National Instruments 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 the LabVIEW "G" language is based on data availability. If there is enough data available to a function, it will execute. The execution flow is determined by the structure of a graphical block diagram (the LabVIEW-source code) on which the programmer places nodes and connects them by drawing wires. A node can be a control, indicator, structure, function, or recursively, another block diagram. An example of a simple four-node block diagram is two controls and an indicator wired to the addition function, causing the indicator to display the sum of the two controls. The wires connecting nodes propagate data as variables, and any node can execute as soon as all its input variables (data) become available. Since this might be the case for multiple nodes simultaneously, LabVIEW can conceptually execute in parallel.[5] 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 program development cycle. LabVIEW programs are collections of one or more virtual instruments (VIs). Each VI has three components, a front panel, back panel, and connector panel, all composed of nodes and wires represented graphically to the user. 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 consists of a block diagram containing the graphical source code. All of the objects placed on the front panel will appear in the back panel block diagram as terminals. The block diagram also contains structures and functions, chosen from a Functions palette, which perform operations on controls and supply data to indicators. The connector panel has terminals whose wires go to or come from nodes in the front and back panels, and is used to represent the VI within the back panel of upstream (calling) VIs and downstream (called) VIs to which it might be connected.

There are two ways to run a VI. It can be run by itself as a program, with the front panel serving as a user interface. Alternatively, it can be treated as a node that is dropped onto the block diagram of another VI and wired to its nodes through the connector panel. In that case it runs as a subroutine within a larger program, and the front panel controls the inputs and outputs of the VI node. Thus, each VI can be easily tested as a stand-alone program before being embedded as a subroutine into a larger program.

The "G" graphical approach allows non-programmers to easily build programs by dragging and dropping virtual representations of lab equipment with which they are already familiar. The LabVIEW programming environment includes examples and documentation to guide and simplify the creation of small applications. As with all introductory programming guides, the ease of construction of working "G" programs may cause the programmer to underestimate 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 that communicate using a simple client–server model which takes advantage of the inherently parallel nature of "G".

Common application design patterns

Applications in LabVIEW are typically designed using well-known architectures 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 VariableExchange information without using global variablesA 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 wiringAll owning virtual instruments (VIs) are kept in memory.
State machine[6] Controlled execution that depends on past eventsCase structure inside a while loop passes an enumerated variable to a shift register, representing the next state; complex state machines can be designed using the Statechart moduleUser interfaces,complex logic, communication protocolsAll possible states must be known in advance.
Event-driven user interfaceLossless processing of user actionsGUI 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 capturedGraphical user interfaceOnly one event structure in a loop.
Master-slave[7] Run independent processes simultaneouslySeveral parallel while loops, one of which functions as the "master", controlling the "slave" loopsA simple GUI for data acquisition and visualizationAttention to and prevention of race conditions is required.
Producer-consumer[8] Asynchronous or multithreaded execution of loopsA master loop controls the execution of two slave loops, that communicate using notifiers, queues and semaphores; data-independent loops are automatically executed in separate threadsData sampling and visualizationOrder of execution is not obvious to control.
Queued state machine with event-driven producer-consumerHighly responsive user-interface for multithreaded applicationsAn 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 VIsComplex applications

Features and Resources

Interfacing to devices

LabVIEW includes extensive support for interfacing to 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 "G" function nodes for controlling the device. National Instruments makes thousands of device drivers available for download on their Instrument Driver Network (IDNet).[9]

LabVIEW has built-in support for other National Instruments products, such as the CompactDAQ and CompactRIO hardware platforms and Measurement and Automation eXplorer (MAX) and Virtual Instrument Software Architecture (VISA) toolsets.

Code compiling and execution

LabVIEW includes a compiler that translates "G" code into native code for supported CPU platforms. The graphical code is converted into Dataflow Intermediate Representation, and then translated into chunks of executable machine code by a compiler based on LLVM. These code chunks are called by the "G" run-time engine, providing for fast, high-performance native execution of the graphical code. The LabVIEW syntax is strictly enforced during the editing process, and when "G" code is run or saved, the compiler is automatically invoked. "G" code is saved to a single binary file that contains both the source and executable code. Execution is controlled by the run-time engine, which contains some pre-compiled code to perform common tasks defined in the "G" language. The run-time engine manages execution flow, and provides a consistent interface to supported operating systems, graphic systems and hardware components. The use of a portable run-time environment makes the source code files portable across supported platforms. LabVIEW programs are slower than equivalent compiled C code, although it is often possible to mitigate speed issues with program optimizations.[10]

Large libraries

LabVIEW includes a large number of libraries containing functions for data acquisition, signal generation, mathematics, statistics, signal conditioning, analysis, integration, filtering, and other specialized abilities such as data capture from hardware sensors. In addition, it includes MathScript, a text-based programming component with built-in functions for signal processing, analysis, and mathematics. MathScript can be integrated with graphical programming using script nodes and uses a syntax that is generally compatible 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 by drawing two or more parallel while loops and connecting them to two separate nodes. This provides 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 platform 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 the 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.

Home Bundle Edition

National Instruments provides a low cost LabVIEW Home Bundle Edition.[13]

Community Edition

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]

Criticism

LabVIEW is a proprietary product of National Instruments. Unlike common programming languages such as C or Fortran, LabVIEW is not managed or standardized by any third-party standards committee.

Non-textual

Since the "G" language is non-textual, common 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, however, some source code control (versioning) tools that do enable code comparison and merging, 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).

Name and version Build number Date Notes
LabVIEW project beginsApril 1983
LabVIEW 1.0October 1986 for Macintosh
LabVIEW 2.0January 1990
LabVIEW 2.5August 1992 first release for Sun and Windows
LabVIEW 3.0July 1993 Multiplatform
LabVIEW 3.0.11994 first release for Windows NT
LabVIEW 3.11994
LabVIEW 3.1.11995 first release with "application builder" ability
LabVIEW 4.0April 1996
LabVIEW 4.11997
LabVIEW 5.0February 1998
LabVIEW RTMay 1999 Real-time
LabVIEW 6.0 (6i)6.0.0.400526 July 2000
LabVIEW 6.16.1.0.400412 April 2001
LabVIEW 7.0 (Express)7.0.0.4000April 2003
LabVIEW PDA moduleMay 2003 first release of the module
LabVIEW FPGA moduleJune 2003 first release
LabVIEW 7.17.1.0.40002004
LabVIEW Embedded moduleMay 2005 first release
LabVIEW 8.0 8.0.0.4005September 2005
LabVIEW 8.20August 2006 native object-oriented programming
LabVIEW 8.2.18.2.1.400221 February 2007
LabVIEW 8.58.5.0.40022007
LabVIEW 8.68.6.0.400124 July 2008
LabVIEW 8.6.18.6.0.400110 December 2008
LabVIEW 20099.0.0.40224 August 2009 32-bit and 64-bit
LabVIEW 2009 SP19.0.1.40118 January 2010
LabVIEW 201010.0.0.40324 August 2010
LabVIEW 2010 f210.0.0.403316 September 2010
LabVIEW 2010 SP110.0.1.400417 May 2011
LabVIEW for LEGO MINDSTORMSAugust 2011 2010 SP1 with some modules
LabVIEW 201111.0.0.402922 June 2011
LabVIEW 2011 SP111.0.1.40151 March 2012
LabVIEW 201212.0.0.4029August 2012
LabVIEW 2012 SP112.0.1.4013December 2012
LabVIEW 201313.0.0.4047August 2013
LabVIEW 2013 SP113.0.1.4017March 2014[19]
LabVIEW 201414.0August 2014
LabVIEW 2014 SP114.0.1.4008March 2015
LabVIEW 201515.0f2August 2015
LabVIEW 2015 SP115.0.1f1March 2016
LabVIEW 201616.0.0August 2016
LabVIEW 201717.0f1May 2017
LabVIEW NXG 1.01.0.0May 2017
LabVIEW 2017 SP117.0.1f1Jan 2018[20]
LabVIEW NXG 2.02.0.0Jan 2018[21]
LabVIEW 201818.0May 2018
LabVIEW NXG 2.12.1.0May 2018[22]
LabVIEW 2018 SP118.0.1Sep 2018[23]
LabVIEW NXG 3.03.0.0Nov 2018[24]
LabVIEW 201919.0May 2019
LabVIEW NXG 3.13.1.0May 2019[25]
LabVIEW 2019 SP119.0.1Nov 2019
LabVIEW NXG 4.04.0.0Nov 2019[26]
LabVIEW 2020 and
LabVIEW NXG 5.0 Community Edition
April 2020[27] first releases
LabVIEW 202121.0August 2021
LabVIEW 2022 Q322.3July 2022
LabVIEW 2023 Q123.1January 2023
LabVIEW 2023 Q323.3July 2023

Repositories and libraries

OpenG and 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.

Tools exist to convert MathML into "G" code.[28]

Related software

National Instruments also offers Measurement Studio, a product that offers many of the test, measurement, and control abilities of LabVIEW as a set of classes for use with Microsoft Visual 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 National Instruments TestStand test management software.

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.

See also

Related software titles
Free and open-source packages

Further reading

Articles on specific uses

Notes and References

  1. Book: Jeffrey., Travis. LabVIEW for everyone : graphical programming made easy and fun.. 2006. Prentice Hall. Kring, Jim.. 0131856723. 3rd. Upper Saddle River, NJ. 67361308.
  2. Book: Software synthesis from dataflow models for G and LabVIEW. November 1998 . 2 . 1705–1709 vol.2 . 10.1109/ACSSC.1998.751616. 7150314.
  3. Web site: Upgrade LabVIEW. Forums. National Instruments.
  4. Web site: NI Releases Free Editions of Flagship Software: LabVIEW. 2020-04-28. www.businesswire.com. en. 2020-04-28.
  5. Book: Bress. Thomas J.. Effective LabVIEW Programming. 2013. NTS Press. [S.l.]. 978-1-934891-08-7.
  6. Web site: Application Design Patterns: State Machines . 8 September 2011 . National Instruments whitepapers . 21 September 2017 . live . https://web.archive.org/web/20170922002635/http://www.ni.com/white-paper/3024/en/ . 22 September 2017.
  7. Web site: Application Design Patterns: Master/Slave . 7 October 2015 . National Instruments whitepapers . 21 September 2017 . live . https://web.archive.org/web/20170922002540/http://www.ni.com/white-paper/3022/en/ . 22 September 2017 .
  8. Web site: Application Design Patterns: Producer/Consumer . . 24 August 2016 . National Instruments whitepapers . 21 September 2017 . live . https://web.archive.org/web/20170922002635/http://www.ni.com/white-paper/3023/en/ . 22 September 2017 .
  9. Web site: 3rd Party Instrument Drivers - National Instruments . live . https://web.archive.org/web/20141128134304/http://www.ni.com/downloads/instrument-drivers/ . 2014-11-28 . www.ni.com.
  10. Web site: NI LabVIEW Compiler: Under the Hood. 4 February 2020. ni.com.
  11. Web site: LabVIEW MathScript RT Module. www.ni.com. live. https://web.archive.org/web/20160805161725/http://www.ni.com/labview/mathscript/. 2016-08-05.
  12. Web site: VIPM Desktop. www.vipm.io. 2023-06-09.
  13. Web site: LabVIEW Home Bundle for Windows - National Instruments. sine.ni.com. live. https://web.archive.org/web/20160704163634/http://sine.ni.com/nips/cds/view/p/lang/en/nid/213095. 2016-07-04.
  14. Web site: LabVIEW Community Edition - National Instruments. www.ni.com. 2020-04-28.
  15. Web site: LabVIEW Community Edition Usage Details - National Instruments. www.ni.com. 2020-04-28.
  16. Web site: Thinking in G » Top 5 bad excuses for not using source code control . live . https://web.archive.org/web/20161028215453/http://thinkinging.com/2007/06/17/top-5-bad-excuses-for-not-using-source-code-control/ . 2016-10-28 . 2016-10-28.
  17. Web site: Software Configuration Management and LabVIEW - National Instruments . live . https://web.archive.org/web/20161029043345/http://www.ni.com/white-paper/4114/en/ . 2016-10-29 . www.ni.com.
  18. Web site: Configuring LabVIEW Source Code Control (SCC) for use with Team Foundation Server (TFS) - National Instruments . live . https://web.archive.org/web/20161028215645/http://www.ni.com/tutorial/14304/en/ . 2016-10-28 . www.ni.com.
  19. Web site: What's New in NI Developer Suite - National Instruments. www.ni.com. dead. https://web.archive.org/web/20140331131311/http://www.ni.com/white-paper/5920/en/. 2014-03-31. 2014-03-31.
  20. Web site: LabVIEW 2017 SP1 Patch Details - National Instruments. www.ni.com. 2018-05-28.
  21. Web site: LabVIEW NXG 2.0 Readme - National Instruments. www.ni.com. 2020-04-28.
  22. Web site: LabVIEW NXG 2.1 Readme - National Instruments. www.ni.com. 2020-04-28.
  23. Web site: LabVIEW 2018 SP1 Readme for Windows - National Instruments. www.ni.com. 2020-04-28.
  24. Web site: LabVIEW NXG 3.0 Readme - National Instruments. www.ni.com. 2020-04-28.
  25. Web site: LabVIEW NXG 3.1 Readme - National Instruments. www.ni.com. 2020-04-28.
  26. Web site: LabVIEW NXG 4.0 Readme - National Instruments. www.ni.com. 2020-04-28.
  27. Web site: NI Releases Free Editions of Flagship Software: LabVIEW. 2020-04-28. www.businesswire.com. en. 2020-04-28.
  28. Web site: Math Node - A new way to do math in LabVIEW. 25 October 2010. ni.com. live. https://web.archive.org/web/20110225172619/http://decibel.ni.com/content/docs/DOC-13859. 25 February 2011.
  29. Web site: Embedding a C/C++ Interpreter Ch into LabVIEW for Scripting. iel.ucdavis.edu. live. https://web.archive.org/web/20110515065700/http://iel.ucdavis.edu/projects/chlabview/. 2011-05-15.