ABSTRACT
In general, there are three basic categories of computer communication operations that can occur. Centralized data communications refers to the transfer of information within a particular computer system. One example is the data that is transferred from an input terminal to the main data processing computer (host) and on to a disk memory or output printer. Figure 8.4 shows the equipment interconnections used with a centralized control system for a machining cell. In this instance, the cell control system consists of a single computer that is in charge of everything. This host computer manages a data base and implements all of the cell control functions, including supporting the data requirements of the individual machine control systems (the application) and executing the necessary logic/rules for the communication task (protocol).
