A virtual instrument in principle is a computer based software driven instrument for test, measurement or process control applications. Virtual instruments are thus composed of layers of software and hardware having a virtual control panel that only appears on a computer display.
In virtual instrumentation systems the appearance of real instruments and measurement workbenches are mimicked so that they resemble the interfaces of their real counterparts. Instead of conventional text-based procedural programming languages where syntax and punctuations are sensitive aspects of a program, visual or graphics-based programming is ideal for virtual instrumentation. Different DAQ (Data Acquisition) Cards are available which are interfaced with our PC. Data Acquisition devices combine data acquisition with the processing power of a computer.
With DAQ devices, the hardware converts the incoming signal into a digital signal that is sent to the computer. The computer receives raw data. Software takes the raw data and presents it in a form the user can understand. Software manipulates the data so it can appear in a graph or chart or in a file for report. The software also controls the DAQ system, telling the DAQ device when to acquire data, as well as from which channels to acquire data.