Reduce The Communication Allocation Reserved For Profinet Io When Operating Alongside Other Services; Prioritized Startup In Profinet Io - Siemens SIMATIC NET S7-400 Manual

6.7.2 Reduce the communication allocation reserved for PROFINET IO when
operating alongside other services.
If cyclic data exchange over PROFINET IO is operating at the same time on the same
Ethernet subnet, set the communications allocation for PROFINET IO in the properties
dialog of the PROFINET IO system to a value <100%.
Reason: At the (default) setting 100%, the communication time is reserved primarily for
PROFINET IO data exchange. Reducing the communications allocation for PROFINET IO
increases the systemwide update time for PROFINET IO and creates additional time on the
CP for processing other communication services.
6.7.3

Prioritized startup in PROFINET IO

Functions
If you use RT or IRT communication, the CP supports the PROFINET functionality
"prioritized startup" for PROFINET IO devices that also support this function. A maximum of
32 PROFINET IO devices can be configured per I/O controller. With these IO devices,
simultaneous startup times with values as low as 0.5 s can be achieved for a maximum of 8
devices.
Prioritized startup is used in fast processes when IO devices change quickly, for example
fast tool changes with a robot.
There is a considerable improvement in performance even in the following situations:
● Applications that generally require a fast start-up time for the IO devices following "Power
on" or following station failure/station return.
● When activating PROFINET IO devices.
Note
Longer start-up times despite prioritized startup
In the following situations, start-up times of up to 8 s may be experienced despite
prioritized startup:
• A PROFINET IO device is disconnected and reconnected within 8 s.
• At a docking point, several physical PROFINET IO devices are docked as one IO
Configuration for IO devices
You configure prioritized startup for the IO devices configured in the PROFINET IO system.
In STEP 7 select the properties of the PROFINET interfaces for the relevant IO devices.
Prioritized startup requires fixed port settings.
CP 443-1 (EX30)
Manual, 03/2019, C79000-G8976-C255-05
device with one specific device name and one specific IP configuration (for example at
a docking point for a driverless transport system).
Configuration and operation
6.7 PROFINET IO mode
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