Siemens SIMATIC ET 200AL, System Manual

Page: 1851 / 2255

Functions
5.13 Accelerating startup
PROFINET with STEP 7
286
Function Manual, 05/2021, A5E03444486-AL
5.13.2 Prioritized startup
Definition
Prioritized startup refers to the PROFINET function for accelerating the startup of IO devices in
a PROFINET IO system with RT communication. It shortens the time that the respective
configured IO devices require in order to reach the cyclic user data exchange in the following
cases:
•
After the power supply has returned
• After a station has returned
• After activation of IO devices
WARNING
Data exchange despite multiple use IP addresses/device names in PROFINET IO system
To achieve higher ramp-up times, the IO controller checks the uniqueness of device name of
IP address parallel to the device ramp-up. In the case of incorrect or double assignment of
device name or IP address, a short-time data exchange is possible until the IO controller
reacts to the error. In this time the IO controller can exchange IO data with the false device.
During commissioning, ensure that no IP addresses / device names are assigned multiple
times in the PROFINET IO system.
Advantages
The PROFINET functionality "prioritized startup" enables PROFINET IO applications in which
machine parts or tools and their IO devices have been permanently replaced. Waiting times of
several seconds between the scheduled processes of the restart are reduced to a minimum by
this optimization. This accelerates the production process with alternating IO devices
(PROFINET functionality "docking systems"), e.g. in tool changer applications, and enables a
greater throughput in production.
The PROFINET functionality "prioritized startup" also offers a considerable increase in
performance for applications where a quick startup time of the IO devices after "power on" or
after station failure / station return is required, or when activating IO devices.