Siemens SIMATIC PCS 7 Configuration Manual page 145

Communication between two H systems
Two H systems must be configured for this section in the project "01_Plant_A".
In this case a "S7 connection fault-tolerant" can be configured between both H systems with
four routes. The number of available routes is displayed via the connection's object properties,
depending on the number of configured CP443-1 and the available networks.
Compendium Part A - Configuration Guidelines (V8.2)
Configuration Manual, 08/2016, A5E38166869-AA
Configuration of the network connections
7.2 Configuration of the connections
145