by July 9, 2003 0 comments



LabView (Laboratory Virtual Instrument Engineering Workbench) from National Instruments is a graphical development environment, that is, it relies on symbols rather than text based languages to describe programming actions. LabView is a product which is primarily aimed at scientists, engineers and alike for simulating different types of instruments. The programs in Labview are called virtual instruments or VI’s. 

A virtual instrument is a combination of a data-acquisition system and a processing system–the computer in this case. The processing involved is soft coded as a program rather than as complex circuitry. The advantages are obvious–cost for one.

The same hardware (DAQ + computer) can act as different instruments without any additional overhead of cost. Flexibility in experimentation–changing the parameters of instruments is as simple as clicking on some button, when dealing with real instruments, things can be different. A lot of mitigating factors like leakage and faulty components also come into play.

Graphical development environment as mentioned above encompasses the concept of data flow programming. Most programming students are however exposed to the control flow paradigm of programming. In a control flow programming, the sequence of the program is defined by the flow of control through the program. In contrast–in a data flow paradigm, the sequence of execution is determined by the flow of data. Data flow programming forms the basis of graphical programming. In LabView, graphical components that are familiar to technicians and engineers are used and the flow of data is implemented by just joining these components by means of “wires”. This methodology has some inherent drawbacks, for example, lack of flexibility provided by a text-based language say C or C++, but it also gives the advantage of reduced development time and effort when used by adept hands. This is an extremely important characteristic–as the intended audience is more of an experimentalist than a programmer, and would probably spend more time analyzing and experimenting with the results.

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Price : Rs 55,000
Meant for : Scientists and engineers who want to simulate instruments
Key Specs : Good networking integration and many prebuilt components
Pros : Intuitive development based on Data flow, very small learning curve and DAQ integration
Contact : National instruments,
Banglore.
E-mail : ni.india@ni.com 

LabView development comprises of creating the flow structure “the code” and the front panel of the instrument. You just have to drag and drop the various components available on the control panel to the one of the “code” windows. All sorts of components are available including signal generators, Boolean operators, DSP components, for example, for doing FFT (Fast Fourier Transform). The front panel forms the user interface of the instruments–components that can go here include buttons, knobs, and screen. Two are easily connected because as soon you put a component on the front panel–a graphical equivalent is also put on the code window. The panel can hence be connected to the internal code. 

Yet another forte of this software is unmatchable support for Data acquisition systems. This can fully interact with hardware supporting standards such as GPIB and RS232. LabView can also call external libraries. Support for networking and ActiveX components is also present. Image-processing components are also at the user’s disposal. The power of this software can be judged from the fact that a full-fledged oscilloscope with realtime data input and Young’s double slit experiment can be both simulated. This programming environment is even versatile for even developing chess like apps.

We reviewed version 6.1. If you have worked with LabView before, you might be interested in knowing that this version has features like remote viewing of an instrument over a network. This essentially means that the front panel of the instrument can exist on a machine, other than that actually has the code of the virtual instruments. Enhancements pertaining to Event driven programming are also there. A point to be noted here is that the version 7 is the latest and not 6.1.

Compared against Matlab, this has the USP of having a graphical-programming environment and many pre-built components.

Also, LabView is geared more towards instrumentation. Documentation and online help is massive and is geared to give even beginners a jump-start. It is also well structured with plenty of examples. Overall, a must for any one who is into instrumentation. 

Ankit Khare and Manas Mittal  with inputs from Mr KPS Rana, Asst Prof, NSIT Delhi.

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