Data Exchange Between Higher- And Lower-Level Io System - Siemens SIMATIC PROFINET Function Manual

Functions
5.2 Intelligent IO devices (I-devices)
5.2.4

Data Exchange between higher- and lower-level IO system

Introduction
The next chapter shows the data exchange between the higher- and lower-level IO system.
Transfer areas
Transfer areas are an interface to the user program of the I-device CPU. Inputs are
processed in the user program and outputs are the result of the processing in the user
program.
The data for communication between IO controller and I-device is made available in the
transfer areas. A transfer area contains an information unit that is exchanged consistently
between IO controller and I-device. You can find more information on configuration and use
of transfer areas in the section Configuring the I-device (Page 106).
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PROFINET with STEP 7 V14
Function Manual, 09/2016, A5E03444486-AG