Virtual Instrumentation using LabView

Virtual Instrumentation

Virtual instrumentation is the process of combining commercial technologies like C, with measurement and control hardware. This produces systems that meet the expectations of applications for engineers and scientists. The industry-standard system that is built using the powerful application software and cost-effective hardware like plug-in boards is called a virtual instrument. 

These virtual instruments enable engineers and scientists to test, control, and design applications. Although the circuit technology has advanced so much, it is the software that leverages the true potential of creating virtual instruments. They provide ways to innovate and reduce costs. Virtual instruments are necessary for product and process design, development, and delivery. 

With virtual instrumentation, engineers can create user-defined instruments that help increase productivity, accuracy, and performance. LabVIEW speeds up the development by using symbolic or graphical representations.

Virtual instruments Vs Traditional instruments

Traditional instruments oscilloscopes and waveform generators are built to perform tasks defined by the vendor. So the user cannot perform their customized tasks. The instruments are developed with built-in circuitry that fits the nature of the instrument. The special technology used in building these instruments is expensive, making the overall instrument very expensive.

As virtual instruments are PC-based, it takes advantage of the latest technology already built within the PCs. Unline the traditional instruments with knobs and switches, the virtual instruments include powerful processors like Pentium 4 and an operating system like Windows, Mac OS, etc. They also make it possible to access the internet.

• A traditional instrument includes an integrated circuit that performs a set of tasks. In a virtual instrument, these functions are performed by the software. So the developers can extend the functionalities easily.
• The traditional instruments have limited connectivity. The virtual instruments have connectivity to networks, applications, and peripherals. 
• The traditional instruments have fixed functionalities. The functionalities of virtual instruments leverage computer technology.
• Traditional instruments require high development and maintenance costs. Virtual instruments have reduced development and maintenance costs.
• The virtual instruments have a better display with color depth and pixel resolution than traditional instruments. 

The software in virtual instruments

The key component of a virtual instrument is the software. With the right software, developers can design, create applications, and integrate routines that the process needs. They can also create a user interface that suits the needs of the application and the users. They explain how the application reads the data from the device, how it processes, manipulates, and stores the data, and how it presents the data back to the user. 

Intelligence and decision-making capabilities can be built into the virtual instruments so that it adapts to the signal changes. It can also specify when processing power is required. The software also provides modularity. When developers work on a project, they divide the task into several sub-tasks. A virtual instrument can be built with reduced dependencies to solve these subtasks and then combine them to make up the main task.  

LabVIEW for virtual instruments

LabVIEW provides an application development environment that is designed specifically to meet the needs of scientists and engineers. It offers features that connect to various hardware and software that make it easy for virtual instrumentation. It provides a graphical programming environment for developers. By using this graphical user interface, developers can create custom virtual instruments. 

Developers can create graphical programs, control selected software, analyze data, and display the results. They can customize and include knobs, buttons, dials, and graphs that emulate control panels. The developers can also represent the control and operation of processes through graphical representation (block diagrams). LabVIEW provides built-in libraries to integrate stand-alone instruments, data devices, vision products, motion controls, and a lot more. 

Key advantages of virtual instrumentation in LabVIEW

• Here are some of the key advantages of virtual instrumentation provided by LabVIEW.
• With LabVIEW, developers can create a framework that seamlessly integrates software and hardware.
• LabVIEW provides communications and data standards like TCP/IP, OPC, XML, SQL Database, etc. 
• It can run on Windows 2000, NT, XP, Mac OS, and Linux. It can also run VenturCom ETS' real-time operating system.
• Developers can build distributed applications on different platforms. The processor-intensive routines can be offloaded to other machines for remote monitoring and faster execution. 
• If the developers need a change in the future, they can easily modify the system without having to buy a new one.
• LabVIEW includes advanced analysis through built-in libraries. 
• National Instruments also provides LabVIEW Signal Processing Toolset, the LabVIEW Sound and Vibration Toolkit, and the LabVIEW Order Analysis Toolkit.
• The collected data can be displayed to the user through charts, graphs, 2D, and 3D visualizations.
• The data presentation attributes can be customized based on colors, font size, graph types, etc.

Elements of virtual instruments

With LabVIEW, developers use a graphical programming language with drag-and-drop icons for creating virtual instruments. LabVIEW uses data flow programming, where the execution order is specified by the flow of data. A virtual instrument contains 3 parts.

Front Panel - It is the user interface through which the users interact with the virtual instrument. 

Block Diagram - It is similar to a flow chart, which includes the code to control the program.

Icon/Connector - It specifies the connection between a virtual instrument with another.

When the program is run, the users can give inputs and observe the given data being updated in real-time. The values through the block diagram are passed through wires or terminals. To start or stop a program, or any other function, controls can be used. The output data can be displayed through thermometers, lights, and any other indicators.

Conclusion

LabVIEW is a great tool for developers to create virtual environments. It provides control, function, and other palettes with graphical icons that can be used in either the front panel or the block diagram. With the many built-in libraries and functionalities, developers can build their own virtual instruments on an open framework, and maintain them for the long term.