I/O configuration variants
4.7 Connecting redundant I/O to the PROFIBUS DP interface
CPU 410-5H Process Automation/CPU 410 SMART
68 System Manual, 10/2013, A5E32631667-AA
RT communication (real-time communication)
The transmission of real-time data with PROFINET IO is based on the cyclic data exchanges
with a provider-consumer model. To better scale the communication options and therefor the
determinism for PROFINET IO, real-time classes have been defined for data exchange.
These are unsynchronized and synchronized communication. The details are handled
independently in the field devices. Real-time automatically includes an increase in priority
with PROFINET compared to UDP/IP frames. This is necessary to prioritize the transmission
of data in the switches so that RT frames are not delayed by UDP/IP frames.
Note
RT communication is interrupted (station failure) if the reconfiguration time of the ring is
greater than the selected response monitoring time of the IO device. The same applies to IO
devices configured with MRP outside the ring.
For additional information, refer to the STEP 7 Online Help and to Manual PROFINET
System Description (http://support.automation.siemens.com/WW/view/en/19292127).
Connecting redundant I/O to the PROFIBUS DP interface
4.7.1
Signal modules for redundancy
Signal modules as redundant I/O
The signal modules listed below can be used distributed as redundant I/O. Take into account
the latest information on the use of modules in the Readme and in the following SIMATIC
FAQ : S7-400H Systems Redundant I/O
(http://support.automation.siemens.com/WW/view/en/9275191)
Note
The statements on the individual signal modules in this section refer exclusively to their use
in redundant operation. Restrictions and special features listed here especially do not apply
to the use of the corresponding module in stand
-alone operation.