Software's Role In Virtual Instrumentation

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Visión General Every virtual instrument is built upon flexible, powerful software by an innovative engineer or scientist applying domain expertise to customize the measurement and control application. The result is a userdefined instrument specifc to the application needs. This document introduces the role of National Instruments software in virtual instrumentation.

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The 3 Layers of Virtual Instrumentation Software What makes LabVIEW ideal for virtual instrumentation? How does virtual instrumentation take advantage of the latest software trends? What is measurement and control services software? Additional Virtual Instrumentation Resources

The 3 Layers of Virtual Instrumentation Software Virtual instrumentation software can be divided into several different layers. 1. Application Software: Most people think immediately of the application software layer. This is the primary development environment for building an application. It includes software such as LabVIEW, LabWindows/CVI (ANSI C), Measurement Studio (Visual Studio programming languages), SignalExpress, and VI Logger. 2. Test and Data Management Software: Above the application software layer the test executive and data management software layer. This layer of software incorporates all of the functionality developed by the application layer and provides system-wide data management. 3. Measurement and Control Services Software: The last layer is often overlooked, yet critical to maintaining software development productivity. The measurement and control services layer includes drivers, such as NI-DAQmx, which communicate with all of the hardware. It must access and preserve the hardware functions and performance. It also must be interoperable –it has to work with all other drivers and the many modular I/O types that can be a part of the solution.

Figure 1. Virtual Instrumentation Software

What makes LabVIEW ideal for virtual instrumentation? LabVIEW is an integral part of virtual instrumentation because it provides an easy-to-use application development environment designed specifically for engineers and scientists. LabVIEW offers powerful features that make is easy to connect to a wide variety of hardware and other software. This ease of use and these features deliver the required flexibility for a virtual instrumentation software development environment. The result is a user-defined interface and user-defined application functionality. One of the most powerful features that LabVIEW offers is its graphical programming paradigm. With LabVIEW, engineers and scientists can design custom virtual instruments by creating a graphical user interface on the computer screen through which they: • • • •

Operate the instrumentation program Control selected hardware Analyze acquired data Display results

They can customize the LabVIEW user interface, or front panel, with knobs, buttons, dials, and graphs to emulate traditional instrument control panels of, create custom test panels, or visually represent process control and operation.

Figure 2. LabVIEW virtual instruments include the user interface and application logic. Determine virtual instrument behavior by connecting icons to create block diagrams, which are natural design notations for scientists and engineers. With graphical programming, engineers and scientists can develop systems more rapidly than with conventional programming languages, while retaining the power and flexibility needed to create a variety of applications. LabVIEW is an open environment that includes ready-to-use libraries for everything from serial, Ethernet, and GPIB communication to motion control, data acquisition, and image acquisition.

How does virtual instrumentation take advantage of the latest software trends? Traditional instrumentation solutions, by nature of their fixed packaging and vendor-defined nature, can’t rapidly adapt to new software technologies. Because of its inherent flexibility, virtual instrumentation is much better suited to incorporating new tools and technology – users can simply upgrade their software, rather than purchase a new system. Over the 20+ years of its development, LabVIEW has tightly integrated cutting edge software technology while still providing a seamless transition from version to version. With the long project lifetimes often found in the test and measurement industry, it’s critical that LabVIEW provide a stable platform for development over many decades. However, to ensure maximum productivity of its users, LabVIEW must also take advantage of new technologies as they arise. Many software packages get caught in the trap of rapid adoption of new technology without regard to longevity. For example, software packages based primarily on the Microsoft platform of technology over the past 15 years have had several instances where their software had to be totally redefined due to

the discontinuity of the latest technology, such as COM, ActiveX, and most recently, .NET. LabVIEW has always incorporated and continues to incorporate these technologies to ensure that the user has access to the latest tools, but integrates them in such a way that there is no need to completely rework existing code. New technologies, such as .NET, can simply be added in to existing applications as needed.

What is measurement and control services software? Measurement and control services software is equivalent to the I/O driver software layer. However, it is much more than just drivers. Though often overlooked, it is one of the most crucial elements of rapid application development. This software connects the virtual instrumentation software and the hardware for measurement and control. It includes intuitive application programming interfaces, instrument drivers, configuration tools, I/O assistants, and other software included with the purchase of National Instruments hardware. National Instruments measurement and control services software offers optimized integration with both National Instruments hardware and National Instruments application development environments. As an example, National Instruments raised the bar for data acquisition software when it introduced NIDAQmx for the Windows OS and increased the ease, speed, and power with which scientists and engineers take measurements. NI-DAQmx leverages several technologies that legacy drivers do not exhibit including multithreading, simplified application programming interface (API), interactive configuration, and intelligent multi-device synchronization. Additionally, NI-DAQmx supports broad ranges of programming languages, devices, buses, sensors, and even mixed signal types. With NIDAQmx, a new user to data acquisition can easily create an application that leverages parallel processing and synchronizes multiple devices all with interactive, configuration-based programming. In addition to new technologies, every copy of NI-DAQmx ships with a collection of measurement services designed to save data acquisition system developers time and money. This collection of measurement services, in addition to NI-DAQmx, offer more software value than any other data acquisition vendor provides with a DAQ device. A few of these measurement services include, Measurement & Automation Explorer (MAX) for configuring, interacting with, and testing your hardware; DAQ Assistant for configuration-based creation of data acquisition tasks; and VI Logger Lite, FREE software specifically designed for data logging.

[+] Ampliar Imagen Table 1. NI-DAQmx includes a high-performance driver and additional software to increase productivity.

Additional Virtual Instrumentation Resources To learn more about virtual instrumentation, use the following resources: • • • • •

About Virtual Instrumentation Virtual Instrumentation versus Traditional Instruments Virtual Instrumentation for Test, Control, and Design Software's Role in Virtual Instrumentation Hardware's Role in Virtual Instrumentation