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Communications
9.13 The Collection and Generation of Process Signals 483
in Decentralized Manufacturing Systems
Not long ago, it was customary to centrally collect all process signals.
The processor and control elements were housed in a central control
cabinet (Fig. 9.44). Today, with automation systems, extensive control
tasks can be solved effectively if these tasks are distributed among
several decentralized self-sufficient systems.
A decentralized structure is illustrated in Fig. 9.45. The sensing,
actuating, and processing sections of subsystems are connected to a
master computer that evaluates signals applied by each subprocess
and sends back control signals.
These subsystems can be realized in different ways—for example,
a PLC or single-board computer could be used as the control system
for the subprocesses. A process computer, personal computer, or
mainframe can be used as a master computer.

FIGURE 9.44 A centralized control system.

FIGURE 9.45 A decentralized control system.