Siemens SIMATIC ET 200AL, System Manual

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Functions
5.2 Intelligent IO devices (I-devices)
PROFINET with STEP 7
Function Manual, 05/2021, A5E03444486-AL
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5.2.2 Properties and Advantages of the I-Device
Fields of application
Fields of application of the I-device:
•
Distributed processing
A complex automation task can be divided into smaller units/subprocesses. This results in
manageable processes which lead to simplified subtasks.
• Separating subprocesses
Complicated, widely distributed and extensive processes can be subdivided into several
subprocesses with manageable interfaces by using I-devices. These subprocesses can be
stored in individual STEP 7 projects if necessary, which can later be merged to form one
master project.
• Know-how protection
Components can only be delivered with a GSD file for the I-device interface description
instead of with a STEP 7 project. The know-how of the user program may no longer be
published.
Properties
Properties of the I-device:
•
Unlinking STEP 7 projects
Creators and users of an I-device can have completely separated STEP 7 automation
projects. The GSD file forms the interface between the STEP 7 projects. This allows a link
to standard IO controllers via a standardized interface.
• Real-time communication
The I-device is provided with a deterministic PROFINET IO system via a PROFINET IO
interface and therefore supports RT (real-time communication) and IRT (isochronous real
time).
Advantages
The I-device has the following advantages:
•
Simple linking of IO controllers
• Real-time communication between IO controllers
• Relieving the IO controller by distributing the computing capacity to I-devices.
• Lower communication load by processing process data locally.
• Manageable, due to processing of subtasks in separate STEP 7 projects