Siemens SIMATIC PCS 7 Function Manual page 131

Procedure
1. In the component view, select the SIMATIC H station and double-click the "Hardware"
object in the detail window.
HW Config opens.
2. If the hardware catalog is not visible, select the View > Catalog menu command.
The hardware catalog opens.
3. Select the IM 153-2 (ET 200M) in which you want to configure the redundant module.
The module overview is displayed in the lower window pane.
4. In the hardware catalog, select a signal module that supports redundancy.
Using drag-and-drop, move the signal module onto a free slot in the IM 153-2 (lower window
pane).
5. Repeat steps 3 and 4 for the second signal module.
The modules for which redundancy is to be configured are inserted.
6. Select the first IM 153-2 again.
7. Double-click the inserted signal module in the module overview.
The "Properties ..." dialog box for this module opens.
8. Open the "Addresses" tab.
9. Select the process image partition in the "Process image" drop-down list.
10.Select the "Redundancy" tab.
11.Select the entry "2 modules" in the "Redundancy" drop-down list.
Fault-tolerant Process Control Systems (V8.1)
Function Manual, 11/2014, A5E34878832-AA
Advantages of fault-tolerant components
4.4 Distributed I/O
131