Extending LabVIEW and Express Technology with LabVIEW SignalExpress

LabVIEW 7.0 Express and the subsequent LabVIEW 7.1 release introduced LabVIEW users to a new, configuration-based approach to programming. Express technologies deliver a higher level programming methodology through Express VIs and Assistants. LabVIEW SignalExpress is an interactive, nonprogramming tool that at first glance appears to be a stand-alone tool that is completely separate from LabVIEW. However, LabVIEW SignalExpress builds upon the same Express technology originally developed for LabVIEW, and SignalExpress tightly integrates with the LabVIEW programming methodology. This document describes how the Express technologies introduced in LabVIEW 7.0 extend to the new LabVIEW SignalExpress application and highlights how LabVIEW SignalExpress expands the value and reach of the LabVIEW language and Express VIs even further.

Review: What Is Express Technology?

Express technology, introduced in LabVIEW 7.0, consists of Express VIs and Assistants. Express VIs group low-level LabVIEW VIs into functional components that you can configure through an interactive dialog box. For example, rather than choose from many different VIs that can generate stimulus waveforms, you can use the Simulate Signal Express VI and specify waveform properties and view the resulting data in the dialog box, as shown in Figure 1. Assistants, another element of Express technologies, simplify the configuration of more complex operations through a wizard interface, such as setting up a data acquisition (DAQ Assistant) or instrument control operation (Instrument I/O Assistant). Express VIs and Assistants automate the process of configuring and connecting a series of low-level VIs in LabVIEW through a single, high-level configuration experience.


LabVIEW users have embraced Express technology because it does not sacrifice the power and flexibility of the core LabVIEW programming language. Both Express VIs and Assistants are configuration tools that streamline the code development process -– ultimately resulting in standard LabVIEW block diagram code executed with the same efficiency and performance as if you had built the block diagram from scratch.

Why LabVIEW SignalExpress?

LabVIEW SignalExpress is an interactive, nonprogramming tool for making measurements. Virtual instrumentation has traditionally been embraced by the test programmers of the world -– scientists and engineers who need to automate repetitive measurements, primarily in validation or production areas. Design engineers who make measurements on lab prototypes in a benchtop setting are accustomed to using traditional box instruments for manual measurements, without as much concern for automation. In addition, most designers spend a large percentage of their time working in design and simulation software packages and therefore are hesitant to invest in another programming tool just to automate their measurements. Design engineers can use LabVIEW SignalExpress to take advantage of virtual instrumentation on their laboratory benches because it provides a heavily interactive user experience, as opposed to a programmatic user experience. In addition, designers can import simulation data from their design tools and interactively visualize and compare their expected results from their designs with the actual measurements from their prototypes. Refer to ni.com/signalexpress for more information about the measurement capability of LabVIEW SignalExpress.

LabVIEW SignalExpress is the first interactive tool built upon a stand-alone notion of Express Technology. LabVIEW SignalExpress contains a collection of functional Express VIs¹ that you can run within a stand-alone interactive environment called the NI Express Workbench.  You can use LabVIEW SignalExpress to define stimulus-response measurement operations by using configuring dialog boxes and by dragging and dropping signals on the graph. For example, Figure 2 shows a simple project that generates a stimulus waveform, measures the response from a prototype board, performs a distortion measurement on the signal, and saves the signal to disk. The generation, acquisition, and analysis steps are configured through easy-to-use dialog boxes, as shown in Figure 3. You display the time and frequency-domain signals by dragging them to the graph. Using this interactive approach, engineers can focus more on exploring the signals and the measurements they need to make and less on the programming required to get their job done.



¹These Express VIs are built on a new, advanced architecture -– you cannot load and run the standard Express VIs from LabVIEW 8.20 in LabVIEW SignalExpress. However, the architecture and development tools for creating these next generation Express VIs that are compatible with the Express Workbench will be available for LabVIEW users to take advantage of in the future.

See Also:
NI LabVIEW SignalExpress

Extending Express Technology to Every Engineer's Desktop

Interactive, menu-driven measurement tools have not succeeded in the past because they could not solve enough of a user's application to be worthwhile. In other words, easy-to-use tools also have to be flexible to be successful. However, the most flexible tools, like programming languages, are traditionally the most difficult to use. In developing LabVIEW SignalExpress, NI engineers recognized this paradox and addressed it by building LabVIEW SignalExpress on the LabVIEW Express technology. Specifically, NI attacked the LabVIEW SignalExpress development challenge with the following approach:

1. Create an interactive environment for configuring and running Express VIs alone without requiring the entire LabVIEW development environment around it.
2. Allow users to extend this interactive environment by writing plug-ins to add functionality to the tool. These plug-ins are built using LabVIEW.
3. Allow users to convert the projects they build in LabVIEW SignalExpress into LabVIEW block diagrams so they can reuse their work.

Refer to ni.com/LabVIEW signalexpress for technical details about extending SignalExpress with LabVIEW.

See Also:
NI LabVIEW SignalExpress

LabVIEWSignalExpress: An Interactive Environment, Extensible with LabVIEW

The combination of LabVIEW SignalExpress and LabVIEW creates a powerful collection of measurement and analysis tools for a much broader audience of engineers. In the past, engineers that are more casual programmers or those who perform measurement tasks infrequently might have shied away from virtual instrumentation because of the learning curve needed to program automated systems. LabVIEW SignalExpress fills the need for the infrequent user who is not yet automating repetitive measurements by providing a more interactive approach.

More importantly, because LabVIEW SignalExpress is extensible, more experienced LabVIEW users can provide VIs as plug-ins for their colleagues in their department or company. For example, candidates for LabVIEW SignalExpress include design engineers making characterization measurements in the design lab or production technicians debugging a production line when failures occur. In either case, a LabVIEW programmer can extend the LabVIEW SignalExpress tool with additional LabVIEW VIs as needed so the design engineer or technician can carry on with his or her work independently. LabVIEW SignalExpress might be a better user experience for these particular cases, but the engine inside the tool is powered by LabVIEW and Express technology. Thus, LabVIEW SignalExpress provides yet another reason to choose LabVIEW as a development platform. The programmers can do their job with LabVIEW, the designers can do their job with LabVIEW SignalExpress, and they can share their work or extend the measurement capabilities of the product when necessary because of the identical underlying technology platform. The end result is that more scientists, engineers, and technicians can experience the cost, performance, and scalability advantages of virtual instrumentation without having to become expert programmers.

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