As a rapid prototyping tool in various measurement and control engineering applications, LabVIEW allows to implement a wide variety of real-world relevant laboratory experiments. Latest projects and experiments in engineering applications are used to simulate the actual job conditions which are bound to a specific hardware and circuit components. In spite of this, we can create the virtual prototype models of real-time systems by incorporating LabVIEW programming language to engineering projects and experiments. Even though we can create and control various projects using LabVIEW with dedicated data acquisition (DAQ) hardware, more economically and to reduce the feasible time constraints, virtual laboratories and projects are introduced.
The LabVIEW based laboratory experiments and projects enable students to integrate various applications so that they can acquire, analyze and present the loads behavior virtually. These virtual laboratory exercises provide a new approach of collecting and analyzing the scientific data and also gave the opportunity for students to develop their skills in programming by virtual instrumentation. Therefore, before discussing some of these virtual laboratory experiments by LabVIEW programming, lets us learn the basics of LabVIEW.
Introduction to LabVIEW Programming Software
LabVIEW stands for Laboratory Virtual Instrument Engineering Workbench, developed which is developed by National Instruments. It is a graphical based programming language used to develop measurement, test, and control systems, data analysis applications using inbuilt graphical functions and wires that resemble a flow chart.
As compared with C++, visual basic, Java and other text-based languages that their program execution is determined by the sequential order of the program elements, LabVIEW follows the data flow for executing the applications. Each element in the LabVIEW is considered as a node which may be input or output. And wires are used to connect these nodes; therefore, a node can be executed when all the input are connected through these wires.
LabVIEW programs are called VI’s (Virtual Instruments) as their appearance resembles operations of physical instruments such as oscilloscopes, multimeters, etc. Each VI consists of three elements such as the front panel, block diagram and sub VIs.
The front panel is a user interface which is used to display controls and indicators. Various controls and indicators are selected from the control palette which is available only on the front panel. This front panel allows the user to pass the inputs and to receive the outputs. These controls include knobs, dials, push buttons, sliders, strings, etc., which supply the data block diagram.
Indicators include LEDs, charts, graphs, strings, etc., which displays the data acquire by block diagram. When an indicator or a control is dragged on to the Front Panel from the control palette, a node corresponding to it appears on the Block Diagram, automatically.
The block diagram consists of graphical source code of corresponding VI. This has terminals, functions, wires, structures, constants, sub VIs, etc. After creating the front panel, we can control those objects on it by adding source code graphically with available functions. The front panel objects appear as terminals on the block diagram, and these terminals exchange the data or information between front panel and block diagram. The Controls, constants and indicators act as input and outputs of the block diagram.
This block diagram code can be constructed with the use of numerous functions in function palette which is available only on the block diagram as like the control palette on the front panel. We can also place sub VIs in the block diagram, which means, once the VI is built, that can be called or used in another VI by placing it in the block diagram.
Virtual Projects or Experiments using LabVIEW
LabVIEW based virtual instrumentation applications can be implemented to various engineering disciplines such as electrical, electronics, mechanical, nuclear, bio-medical and other engineering departments. This software allows the creating of application-specific projects or experiments to reduce the production time for real-time hardwares. As examples of some of these virtual experiments, two engineering disciplines virtual laboratories are discussed below.
Electrical and Electronics Engineering
The applications of electrical circuits, electromechanical energy conversion devices, power electronics converters, power systems and electrical machines and in engineering education can be tested with pure-simulation or by the real-measurement using hardware equipments. The VIs in this discipline includes determination of electrical machine characteristics, analysis of various parameters in power system networks, AC and DC circuit analysis, and so on. These LabVIEW programming based experiments provide self studying laboratory modules for electrical engineering students.
LabVIEW Programming for Virtual Electrical Circuits Laboratories
A new introductory circuits laboratory uses LabVIEW which enables the students to examine the series and parallel, open and short circuits, various circuit theorems like Thevinens, Nortons, mesh analysis, etc. This tool allows the user to change and modify the circuit by varying its controls on front panel.
The below figure shows a simple DC circuit simulation for finding the current flow by implementing Ohms law to it. We can also vary the circuit components using numeric controls on front panel, as shown in below figure.
LabVIEW Programming for Virtual Electrical Machines Laboratory
The latest trends in eLearning introduces new models of teaching; here, in this case the LabVIEW software is used for simulating electrical machines laboratory. The fundamental equations of DC machines, transformers, induction motor and synchronous motors implemented in this tool for simulating various characteristics of these machines. Due to the graphical user interface, controlling and analyzing of the these machines become easy with graphs and charts. Some of these simulated experiments include load characteristics of DC motor, open and short circuit test of transformer, load characteristics of generator, voltage regulation of transformer, load test on induction motor, and so on.
LabVIEW Programming for Virtual Power System Analysis
In this LabVIEW tool is used for implementing simulation of power system network to analyze the power system loads whether industrial, commercial or residential. Since LabVIEW is a user-friendly programming language and easy to learn software, students can easily build power system modules. These simulation experiments or virtual projects include load analysis, single phase circuits, balanced and unbalanced load simulation, three- phase electric power generation using delta and Wye generators, modeling of transmission lines which can be short, medium and long transmission lines and so on.
The below figure shows the LabIEW VI for daily load analysis wherein front panel has controls like time period and load arrays and indicators numeric indicators and graphs as shown below.
We can also implement virtual projects or experiments in various disciplines of engineering like electronics, mechanical, etc. Consider the example, for lighting below display system many LED lights are required as hardware design. But virtually it is easy to design a simple display lighting system with a LabVIEW software.
Here, the LabVIEW front panel allows a user to design, Boolean controls in name format as EDGEFX in the above figure. Number of iterations given in numeric controls blinks the display that many times as we can observe that the color changes blue to pink as in this case.
From educational point of view, it is clear and expected that new way of teaching or learning through this LabVIEW programming based experiments provides a significant role for identifying, analyzing and presenting the results of a particular system. Hope you have understood the whole concept and for any queries, please comment below.