Integrated instrumentation system

VIRTUAL INSTRUMENTATION

An instrument in a measurement system is a device designed specifically for collecting data from an environment or from a unit under test and to display information based on the collected data. The instruments used in measuremens are known as measurement system. The generalMeasurement system follows a simple block diagram.A traditional measurement system or traditional instrumentation system involves sensors or transducers, signal conditioning elements, signal processing elements, display devices. A sensor senses changes in a physical parameter such as temperature, pressure,level etc, and converted into electrical signal (voltage, current,frequency etc.) through signal conditioning elements (such as deflection bridges, amplifiers, current transmitters etc.) according to the requirements of the user. Now these electrical signal are processed under signal processing elements for further operations such as display or data storage.

During the early ages instrumentation systems originated from measurement of rods, thermometers,measuring pressure. Now in modern measurement systems usually there involves individual instruments for different purposes.for example an electro-mechanical pressure gauge.during 1980’s some complex systems were employed such as chemical process control application.this involves a set of physical instruments wired to a central control panel consisting of an array of physical data display devices such as dials, counters together with switches, knobs and buttons for controlling the instruments.The involvement of computer in the field of instrumentation began as a way of coupling an individual instrument to a computer to feed the measured data to the software on the computer for further processing made a revolution in the field of measurement system. The requirement of an integrated measurement system which involves the user controlling the measurement system from a computer desktop produced the concept of virtual instrumentation.Introduction of computers into the field of instrumentation began as a way o couple an individual instrument, such as a way to couple an individual instrument, such as pressure sensor to a PC and enable the display of measured data on a virtual instrumentation panel contatining butons, scrolls for controlling the operation of the sensor. Thus development of such instrumentation software enabled the creation of simulated physical instrument (Virtual instrumentation) having the capability to control the physical sensing components.

Virtual instrumentation thus refers to the use of geneal purpose components, in combination with data collection hardware devices and vi software to construct an integrated measurement system.

Here the data collection hardwares intemately coupled to the computer where the operation of sensors are controlled by the PC. The collected data are presented before the user as its requirement.

During 1990’s programming of vi systems was a task strictly for professional programmers who wrote the required software using textual Programming languages such as BASIC,C,C++,PASCAL etc. It typically results in production of a consisting of many pages of source code written in a computer language that is totally unreadable by the non-programmers.Hence another disadvantage araised that one customers measurement application was rarely suitable for another customer.eg->one customer may have needed only to collect a single value once in an hour and to have all collected values stored in a file. The next customer may require some of thebvalues to be displayed. To avoid this different technologies have been employed such as LabVIEW, MATLAB,VB,Visual C++ etc.