Assigning Parameters To Modules In A Fault-Tolerant Station - Siemens SIMATIC S7-400H System Manual

15.1.3

Assigning parameters to modules in a fault-tolerant station

Introduction
Assigning parameters to modules in a fault-tolerant station is no different from assigning
parameters to modules in S7-400 standard stations.
Procedure
All parameters of the redundant components (with the exception of MPI and communication
addresses) must be identical.
The special case of CPUs
You can only set the CPU0 parameters (CPU on rack 0). Any values that you specify are
automatically allocated to CPU1 (CPU on rack 1). You can set the following values for
CPU1:
● Parameters of the MPI/DP interface (X1)
● Parameters of the DP interface (X2)
● Addresses of sync modules
● Parameters of the PROFINET interface
Configuring modules addressed in the I/O address space
Always configure a module that is addressed in the I/O address space so that it is located
either entirely in the process image or entirely outside.
Otherwise, consistency cannot be guaranteed, and the data may be corrupted.
I/O access using word or double word operations
The system loads the values to accumulator "0" if the word or double word for I/O access
contains only the first or the first three bytes, but not the remaining bytes of the addressed
space.
Example: The I/O with address 8 and 9 is available in the S7-400H; addresses 10 and 11 are
not used. Access L ID 8 causes the system to load the value DW#16#00000000 into the
accumulator.
S7-400H
System Manual, 03/2012, A5E00267695-11
Configuring with STEP 7
15.1 Configuring with STEP 7
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