Author:
Oleg V. Serdyukov
Affiliation:
Institute of Automation and Electrometry, Siberian Brunch Russian Academy of Science, Russian Federation
Keyword(s):
DCS, controllers, networks, Ethernet
Abstract:
Modern DCS of technological processes have “multi-level” architecture. The “low” level of DCS is represented by controllers. They provide three main functions: data acquisition, processing and control of object. Input-output devices are connected directly to controller for information interchange with object and processing unit (CPU). The upper level connects controllers together and provides their interaction with "the top" level of a system. In systems with such architecture, controller which needs to obtain variables connected to an other controller, it requires to have a special complex service for interconnection with the other controller: for performance of base “low” level function of input-output, upper level is involved. Many suppliers of control systems do not have a solution for it, i.e. the data exchange function of controller in vast majority of systems is absent. Level of today's network technologies allows to construct homogeneous “one-level” control system on the bas
is of a high-efficiency local network, for example Fast Ethernet. In such systems network is used not only for interaction of workstations, servers, but for direct interaction with input-output devices, connected directly to Fast Ethernet network. Thus the concept of classical controllers disappears and control algorithms may be carried out in any point of the system.
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