Siemens SIMATIC ET 200AL, System Manual

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Glossary
PROFINET with STEP 7
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Function Manual, 05/2021, A5E03444486-AL
Prioritized startup
Prioritized startup denotes the PROFINET functionality for accelerating the startup of IO
devices operated on a PROFINET IO system with RT and IRT communication. It reduces the
time that the correspondingly configured IO devices require in order to return to cyclic user
data exchange in the following cases:
•
After the power supply has returned
• After a station has returned
• After activation of IO devices
Process image (I/O)
The CPU transfers the values from the input and output modules to this memory area. At the
start of the cyclic program, the CPU transfers the process image output as a signal state to the
output modules. The CPU then transfers the signal states of the input modules to the process
image of the inputs. Then the CPU executes the user program.
PROFIBUS
Pro cess Fi eld Bus - European Fieldbus standard.
PROFIBUS device
A PROFIBUS device has at least one PROFIBUS interface with an electrical (RS485) or optical
(polymer optical fiber, POF) interface.
PROFIBUS DP
A PROFIBUS with DP protocol that complies with EN 50170. DP stands for distributed I/O (fast,
real-time capable, cyclic data exchange). From the perspective of the user program, the
distributed I/Os are addressed in exactly the same way as the centralized I/Os.
PROFIBUS Users Organization
Technical committee dedicated to the definition and development of the PROFIBUS and
PROFINETstandard. Additional information can be found on the Internet (Page ).
PROFIenergy
Function for energy saving in the process, for example, during pause times by briefly
switching off the entire system via standardized PROFIenergy commands.
PROFINET
Open component-based industrial communication system based on Ethernet for distributed
automation systems. Communication technology promoted by the PROFIBUS Users
Organization.