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Exchange by information between levels

All levels of pyramid must have vertical informatively-technical connection with each other; between them an exchange comes true by information. This exchange takes place information in both sides, from a top to low and from low to top. We will consider such "vertical communication" on the example of the field level - control level. Data from a process, e.g., measuring sizes are subject to the transmission on the local level of basilar automation. The question is about a few quantity of information being actual in certain moment of time, however, with a high requirement to speed of information transfer, e.g., report about the state of danger, that must result in the scram of aggregate. Separate sensors and executive elements on working today options frequently do not have yet own logic and added directly to the level of management. About communication it is yet impossible in own sense to talk, as information arises up constantly, e.g., as an analog signal. But also influence of microelectronics is already noticeable here. So, sensors, capable independently to process signals, produce the rough-down of measuring sizes, compare normal and maximum values or get and pass a few values, begin to use. These "intellectual" sensors are already reported with each other move, thus, part of tasks of automation to the field level. The same succeeds, in general, to increase the productivity of processing of data and simultaneously to shorten communication between the field level and standing above him level of basilar automation, as on a top level relevant data are passed only in a condense form. Logic of components is more expressed at the level of control. Already today they are reported not only with the systems of standing higher level of control by a production, but also with components into the level. Requirements to communication on hierarchical levels are different. At field level drives and sensors are reported mainly very intensively with each other or with a higher level; thus the volume of information is relatively small and period of service of data is small. But the high requirements of short time of reaction require communication in real time. With growth of levels in the hierarchy of task of automation centralized a force character in a greater degree. Although quantity of devices participating in the process of automation reduces, these devices become more producing. Frequency of separate transmissions between them grows short, but, opposite, a size and term of actuality of blocks of data increase, requirements fall down to the real time. In spite of these distinctions, a requirement in horizontal and vertical communication meets on all levels.

Thus every level works mainly with data that is inferior him. Data that must be passed on higher levels, it is necessary in the beginning to abbreviate and squeeze. Related to it an informative concentration prevents to that one level was overloaded by data from other level. Data that must be passed on a lower-level, it is necessary before it to extend additional information. If these principles at structuring of task of automation will be executed: if every level will be independent, as far as maybe, and exchange information between levels will be to minimum, then the volume of horizontal stream of information will increase on every level.



At direct connections (point-to point connections), communication between two components of one level is possible only through a higher level. Partly it introduces a long way for passing of information. Information can be late, if the higher system appears with a limit carrying capacity.

In particular on low levels, where a rapid transmission is especially important, for horizontal communication, for "transversal motion" into one level, it is needed to go another way. All devices and systems of level automations between that there are communicative relations must be related to each other. Otherwise speaking: every partner of communication must be connected with each other. In the large projects of automation such structure will become tangled soon.

Communication into the different levels of automation - from the field level to the level of planning - produces different requirements to the tire. A large value for power and cost of tire of communication of data is had method and amount of transferrable data. At field level between many partners data are passed a few and to the high degree of actuality. An environment of transmission must be inexpensive. What higher hierarchical position, the more descriptions have transferrable data. It means that between not many partners the large packages of given, being actual long time, are passed. Tire must get along at such information content. Regardless of topology of network for communication the different environments of transmission are used.

 


Date: 2015-12-24; view: 548


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