ABSTRACT
Data acquisition includes everything from gathering data, to transporting it, to storing it. The term data
acquisition is described as the ‘‘phase of data handling that begins with sensing of variables and ends with a
magnetic recording of raw data, may include a complete telemetering link’’ (McGraw-Hill, Dictionary of
Scientific and Technical Terms, Second Edition, 1978). Here, the term variables refers to those physical
quantities that are associated with a natural or artificial process. A data acquisition phase involves a real-time
computing environment where the computer must be keyed to the time scale of the process. Figure 6.1 gives a
simplified block diagram of a data acquisition system current in the early 1990s.
