Data acquisition

Data acquisition is the process of measuring physical quantities such as temperature, pressure, voltage or position and bringing those measurements into a computer so they can be recorded, displayed and analysed. The physical world is continuous, while a computer works with numbers, so a data acquisition system bridges the two: it senses a real-world signal, prepares it and converts it into a stream of digital values. This makes it possible to log experiments, monitor machinery and control processes automatically.

A typical system has several stages. A sensor, or transducer, turns a physical quantity into an electrical signal. Signal conditioning then prepares that signal, for example by amplifying weak voltages, filtering out noise or providing electrical isolation. The conditioned signal reaches an analog-to-digital converter, which samples it at regular intervals and represents each sample as a number; the sampling rate and the converter's resolution determine how faithfully the original is captured. The digital values are finally passed to the computer over an interface.

Many interfaces are used to move the data, including the serial standards RS-232 and RS-485, USB, and fieldbus protocols such as Modbus, as well as plug-in cards inside the computer. On the software side, measurements can be handled by general programming languages such as Visual Basic, captured into a spreadsheet like Excel, or processed in environments built for the purpose. LabVIEW is a widely used example: a graphical programming environment in which a measurement and control program is assembled by wiring together blocks rather than writing lines of text, which suits the dataflow nature of acquisition tasks.

Frequently asked questions

What is an analog-to-digital converter?

It samples a continuous electrical signal at regular intervals and turns each sample into a number, allowing a computer to store and process a real-world measurement.

Why is signal conditioning needed?

Raw sensor signals are often weak, noisy or at the wrong level. Conditioning amplifies, filters or isolates them so they can be measured accurately and safely.

What is LabVIEW?

It is a graphical programming environment for measurement and control in which programs are built by connecting blocks visually, well suited to data acquisition tasks.