Siemens SIMATIC ET 200AL, System Manual

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Functions
5.2 Intelligent IO devices (I-devices)
PROFINET with STEP 7
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Function Manual, 05/2021, A5E03444486-AL
Example - the I-device as IO device and IO controller
The I-device as IO device and IO controller is explained based on the example of a print
process. The I-device controls a unit (a subprocess). One unit is used, for example, to insert
additional sheets such as flyers or brochures in a package of printed material.
Figure 5-9 Example - the I-device as IO device and IO controller
Unit 1 and unit 2 each consist of an I-device with centralized I/O. The I-device along with the
distributed I/O system (for example ET 200) forms unit 3.
The user program on the I-device is responsible for preprocessing the process data. For this
task, the user program of the I-device requires default settings (for example control data)
from the higher-level IO controller. The I-device provides the higher-level IO controller with
the results (for example status of its subtask).