Configuration and operation 
  6.7 PROFINET IO mode 
CP 443-1 Advanced (GX30) 
Manual, 03/2019, C79000-G8976-C256-05 
75 
There is a significant improvement in speed even in the following situations: 
●  Applications that generally require a fast start-up time for the IO devices after turning on 
the power 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 
 
  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 
device with one specific device name 
and one specific IP configuration (for example at 
a docking point for a driverless transport system). 
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. 
You will find further information on this in the system descriptions of PROFINET IO /19/ 
(Page 122) /20/ (Page 122). 
 
Note 
Changing the configuration - behavior on startup 
After chang
ing the configuration of an IO device to prioritized startup, the time required for 
the first startup is just as long as without prioritized startup. All subsequent startups will then 
be completed in the reduced time.
 
 
Note 
Inclusion in the MRP ring topology impractical 
Including an IO device with prioritized startup in a ring topology with media redundancy 
serves no practical purpose since the ring is interrupted at each device change.
 
 
IRT communication: Types of synchronization 
Within an IRT domain (Isochronous Real Time), you can use the CP for IRT communication. 
The CP supports IRT communication with the IRT option "high-performance". The IRT option 
"high-performance" optimizes data traffic as the result of topology planning. 
The IRT option "high flexibility" is now only supported when a CP GX20 is replaced.