Siemens SIMATIC S7-400H System Manual page 186

Using I/Os in S7–400H
13.4 Connecting redundant I/O to the PROFIBUS DP interface
Hardware configuration and project engineering of the redundant I/O
Follow the steps below to use redundant I/O:
1. Insert all the modules you want to operate redundantly. Remember the following basic
2. Configure the module redundancy using HW Config in the object properties of the
3. Enter the remaining redundancy parameters for the input modules.
Note
System modifications during operation are also supported with redundant I/O. You are
not permitted to change the parameter settings for a redundant module per SFC.
186
rules for configuration.
relevant module.
Either browse for a partner module for each module, or accept the default settings
In a centralized configuration: If the module is in slot X of the even-numbered rack, the
module at the same slot position in the next odd-numbered rack is proposed.
If the module is in slot X of the odd-numbered rack, the module at the same slot position
in the previous even-numbered rack is proposed.
Distributed configuration in a one-sided DP slave: If the module is inserted in slot X of the
slave, the module at the same slot X of the slave at the same PROFIBUS address in the
partner DP subsystem is proposed, provided the DP master system is redundant.
Distributed configuration in a switched DP slave, stand-alone mode: If the module in the
slave with a DP address is inserted in slot X, the module in the slave with the next
PROFIBUS address at slot X is proposed.
NOTICE
Always switch off power to the station or rack before you remove a redundant digital
input module that does not support diagnostics functions and is not passivated. You
might otherwise passivate the wrong module. This procedure is necessary, for example,
when replacing the front connector of a redundant module.
Redundant modules must be in the process image of the inputs or outputs. Redundant
modules are always accessed using the process image.
When using redundant modules, select the "Cycle/Clock Memory" tab from "HW Config
-> Properties CPU 41x-H" and set the following:
"OB 85 call on I/O area access error > Only incoming and outgoing errors"
System Manual, 03/2012, A5E00267695-11
S7-400H