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6.5
PROFINET IO
6.5.1
How PROFINET IO devices start up in a large configuration
When operating the module with a large configuration (up to 32 communications connections
and up to 32 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 PN IO operating as a 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 monitoring times may need to be increased on the CPU (Properties dialog,
"Startup" tab).
6.5.2
PROFINET IO when operating other services at the same time
Sporadically used services
Note the following if you are using functions alongside PROFINET IO that affect the
configuration or the operating status (FB55, Primary Setup Tool, STEP 7, NCM Diagnostics):
Note
The functions listed above can influence the flow in PROFINET IO so that an interruption of
cyclic IO data exchange of the PROFINET IO devices lasting several seconds may occur.
6.5.3
Effects of multicast communication on RT communication
Note
If PROFINET IO RT communication is operated at the same time as broadcast (BC) or
multicast (MC) in an industrial Ethernet subnet, RT frames can be delayed by long BC
frames or MC frames.
Among other things, these frames can be generated by the communications FCs AG_SEND
or AG_RECV.
With certain constellations, this can lead to a PROFINET RT communication abort. The
factors that influence this are the switch configurations ("switch depth"), the update time and
the MC/BC frame lengths.
You will find further information about the influencing factors as well as possible solutions in:
29104898 (http://support.automation.siemens.com/WW/view/en/29104898)
CP 343-1
Manual, 10/2012, C79000−G8976−C201-07
Notes on configuration and operation
6.5 PROFINET IO
45
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