Siemens SIMATIC S7-400H System Manual page 182

Using I/Os in S7–400H
13.4 Connecting redundant I/O to the PROFIBUS DP interface
Principle of module-specific redundancy
Redundancy always applies to the entire module, rather than to individual channels. When a
channel error occurs in the first redundant module, the entire module and all of its channels
are passivated. If an error occurs on another channel on the second module before the first
error has been eliminated and the first module has been depassivated, this second error
cannot be handled by the system.
An up-to-date list of modules with redundancy capability can be found in section Signal
modules for redundancy (Page 187).
"Functional I/O redundancy" block libraries
The blocks you use for channel group-specific redundancy are located in the "Redundant IO
CGP V50" library. The blocks in the library "Redundant IO CGP V40" can also be set for
channel group-specific redundancy but only for a limited range of modules.
The blocks you use for module-specific redundancy are located in the "Redundant IO MGP
V30" library. Module-specific redundancy is a special form of redundant module operation;
see above.
Note
Operating redundant modules
When you are operating signal modules for the first time, use channel group-specific
redundancy with the blocks in the "Redundant IO CGP V50" library. This ensures maximum
flexibility when using redundant modules.
The "Functional I/O redundancy" block libraries that support the redundant I/O each contain
the following blocks:
● FC 450 "RED_INIT": Initialization function
● FC 451 "RED_DEPA": Initiate depassivation
● FB 450 "RED_IN": Function block for reading redundant inputs
● FB 451 "RED_OUT": Function block for controlling redundant outputs
● FB 452 "RED_DIAG": Function block for diagnostics of redundant I/O
● FB 453 "RED_STATUS": Function block for redundancy status information
Configure the numbers of the management data blocks for the redundant I/O in HW Config
"Properties CPU -> H Parameter". Assign free DB numbers to these data blocks. The data
blocks are created by FC 450 "RED_INIT" during CPU startup. The default setting for the
numbers of the management data blocks is 1 and 2. These data blocks are not the instance
data blocks of FB 450 "RED_IN" or FB 451 "RED_OUT".
You can open the libraries in the SIMATIC Manager with "File -> Open -> Libraries"
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System Manual, 03/2012, A5E00267695-11
S7-400H