Virtual Instrumentation is the use of customizable software and modular measurement hardware to create user-defined measurement systems, called virtual instruments.
Traditional hardware instrumentation systems are made up of pre-defined hardware components, such as digital multimeters and oscilloscopes that are completely specific to their stimulus, analysis, or measurement function. Because of their hard-coded function, these systems are more limited in their versatility than virtual instrumentation systems. The primary difference between hardware instrumentation and virtual instrumentation is that software is used to replace a large amount of hardware. The software enables complex and expensive hardware to be replaced by already purchased computer hardware; e. g. analog to digital converter can act as a hardware complement of a virtual oscilloscope, a potentiostat enables frequency response acquisition and analysis in electrochemical impedance spectroscopy with virtual instrumentation.
The concept of a synthetic instrument is a subset of the virtual instrument concept. A synthetic instrument is a kind of virtual instrument that is purely software defined. A synthetic instrument performs a specific synthesis, analysis, or measurement function on completely generic, measurement agnostic hardware. Virtual instruments can still have measurement specific hardware, and tend to emphasize modular hardware approaches that facilitate this specificity. Hardware supporting synthetic instruments is by definition not specific to the measurement, nor is it necessarily (or usually) modular.
Leveraging commercially available technologies, such as the PC and the analog to digital converter, virtual instrumentation has grown significantly since its inception in the late 1970s. Additionally, software packages like National Instruments' LabVIEW and other graphical programming languages helped grow adoption by making it easier for non-programmers to develop systems.
Simplifying the development process
Virtual instrumentation has led to a simpler way of looking at measurement systems. Instead of using several stand-alone instruments for multiple measurement types and performing rudimentary analysis by hand, engineers now can quickly and cost-effectively create a system equipped with analysis software and a single measurement device that has the capabilities of a multitude of instruments.
Powerful off-the-shelf software, such as our own company's LabVIEW, automates the entire process, delivering an easy way to acquire, analyse, and present data from a personal computer without sacrificing performance or functionality. The software integrates tightly with hardware, making it easy to automate measurements and control, while taking advantage of the personal computer for processing, display, and networking capabilities.
The expectations of performance and flexibility in measurement and control applications continue to rise in the industry, growing the importance of software design. By investing in intuitive engineering software tools that run at best possible performance, companies can dramatically reduce development time and increase individual productivity, giving themselves a powerful weapon to wield in competitive situations.
Preparing investments for the future
Measurement systems have historically been 'islands of automation', in which you design a system to meet the needs of a specific application. With virtual instrumentation, modular hardware components and open engineering software make it easy to adapt a single system to a variety of measurement requirements.
To meet the changing needs of your testing system, open platforms such as PXI (PCI eXtensions for Instrumentation) make it simple to integrate measurement devices from different vendors into a single system that is easy to modify or expand, as new technologies emerge or your application needs change. With a PXI system, you can quickly integrate common measurements such as machine vision, motion control, and data acquisition to create multifunction systems without spending valuable engineering hours making the hardware work together. The open PXI platform combines industry-standard technologies, such as CompactPCI and Windows operating systems, with built-in triggering to provide a rugged, more deterministic system than desktop PCs.
