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| Automation Today |
Today’s state of the art in automation shows a clear trend towards hardware decentralization
in connection with fieldbus systems.
In addition, the development of decentralized software offers considerable
potential for increasing machine output while simultaneously reducing costs.
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Increasing fieldbus use requires greater SPC computing power, since there is a
steadily growing number of signals to be processed and programs are becoming more complex.
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Fieldbusses themselves cannot simply transport information at any speed we might like them to,
owing to technological constraints on transmission capacity. Therefore, increasingly long transfer
times for certain kinds of information will have a negative effect on the performance of the overall system.
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Employing numerical axes places high demands on the reaction speed of the control unit.
Besides, it is impossible to avoid numerical operations with floating-point operands.
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| Advantages of decentralized axis control units |
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Reducing the burden on the SPC: decentralized axis control units handle the subprocessing tasks on their own |
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Reducing the burden on the fieldbus: it is no longer necessary to transfer process data cyclically |
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Shortening response times: time-critical signals will be processed directly by the axis control units |
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| Demands placed on decentralized axis control units |
| In order to be able to cope with the most diverse tasks, decentralized axis
control units must meet the following criteria:
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modularity: subprocesses can vary (number of axes, process signals ...) |
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variable processor power |
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can control various types of axes: server and stepper motors; can perform position measurements, either incrementally or absolutely; can deal with mixed arrangements ... |
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can process digital and analog signals |
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open interfaces: process data often come from external devices |
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short response times, above all for process signals and when controlling axes |
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ree programmability |
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data types: it has to be possible to process long-integer and floating-point data |
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flexible axis control, for example, coordinated movement, altering velocity after starting up |
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access to the axes by program |
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multi-tasking in program sequence |
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greater flexibility when exchanging data among programs by using global variables |
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online access |
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| Conventional SPCs cannot fulfil all the criteria listed above. |
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| Promicon – Your specialist for control technology and drive engineering |
With Promicon, these subprocesses can be automated within one installation, completely
and without any sacrifice in autonomy.
If desired, they can be easily put into decentralized operation for the time being.
While the installation is being built up, operations can be done in parallel.
Implementing the subprocesses is done independent from the central SPC.
The result will be that the productivity of all the machines will increase while costs will be lowered. |
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