Siemens CP 443-1 Manual page 43

Multicomputing Mode − Assigning the CP to the CPU
If you use the CP in an S7 station with several CPUs (multicomputing) for
PROFINET IO operation, you must assign the CP to a CPU in the configuration.
Notice
S
CP slot in PROFINET IO mode
PROFINET IO operation is possible only with one CP located in the central
unit.
S
CPU "startup" configuration when using the IE/PB Link PN IO
If you use the IE/PB Link PN IO as PROFINET IO device, you must select the
option "Startup when expected/actual config. differ" for the CPU in the "Startup"
tab. Otherwise your system will not start up automatically after power up or
following a power outage.
Configuration Limits
When using the CP type described here, the following limits apply within an
S7−400 station:
Number of CPs operating as PROFINET IO controllers: 4
How PROFINET IO devices start up with a large operational configuration
When operating the module with a large configuration (up to 128 communication
connections and up to 125 PROFINET IO devices), it may take several minutes
when the station starts up before all PROFINET IO devices have received
configuration data from the PROFINET IO controller. The IE/PB−Link operating as
PROFINET IO device is particularly affected by this.
To ensure that the CPU does not interrupt the distribution of project engineering
data in this situation, the parameter assignment monitoring time must be increased
on the CPU.
Possible remedy: Reduce the size of the configuration (for example, distribution on
several CPs).
CP 443-1 Advanced for Industrial Ethernet / Manual Part B4A
Release 01/2007
C79000-G8976-C193-06
6 Using the CP 443−1 Advanced for PROFINET IO
B4A−43