Data Aquisition

Data Aquisition

Data aquisition (DAQ) is the sampling of actual physical conditions such as property or phenomena, which can include things such as light intensity, fluid flow, gas pressure, temperature and force. While data acquisition is typically performed for one type of physical condition at a time, some types of data acquisition can take samples of various physical conditions at the same time. Once the data from the physical conditions is collected, the data acquisition process involves converting that data into digital numeric values. This conversion must be performed to attain a unified form that can then be manipulated by a computer. Types of computers that are most commonly used in data aquisition processes are personal computers (PC), PC-based industrial computers, desktop computers and Apple Macintosh computers. Data aquisition can be performed through either data aquisition devices such as temperature or data recorders, or it can be performed as part of an entire data aquisition system.

There are many different types of data aquisition devices and systems, but the basic process of data aquisition remains the same; the main difference is the information and how it is converted into digital form. In order for the conversion to occur, data acquisition devices must have three essential components: sensors, signal conditioners and analog-to-digital converters. These three devices essentially all serve the major purpose of converting the physical data to digital data: the sensors convert the physical data into an electrical signal such as a voltage or a current, then the signal conditioner alters the electrical signal into a form that is able to more easily be converted into digital data, and lastly the analog-to-digital converter is able to take the final step and convert the data fully into digital numerical values. Signal conditioners are not always a necessary component since, at times, the sensor is able to convert the physical data into a form that can easily be converted to digital data on its own. In addition to these three components, data acquisition devices are controlled by means of software programs that have been developed through the use of diverse general-purpose programming languages including Fortran, C, Java, BASIC and Pascal. Additional types of programming that are used for data acquisition systems include graphics software such as ladder logic and Visual Basic.