Siemens SIMATIC Compact FF Link - Startup Behavior in Redundant Mode

8.4.2 Startup behavior in redundant mode
Startup diagram of the bus link with 2 Compact FF Links on SIMATIC S7 41xH
The two Compact FF Links are addressed independently during startup:
● Each DP master configures and parameterizes its assigned Compact FF Link
(independently of the other DP master) and sends the corresponding configuration.
● In fault-free operation, the Compact FF Link that is connected to the subsystem of the
master CPU is activated.
● Once the partner DP master has also successfully completed the configuration, parameter
assignment, and transfer of all configuration data to its Compact FF Link, the
Compact FF Link is available as standby.
The Compact FF Link on the subsystem of the standby CPU is passive. If the active
Compact FF Link fails, it can continue processing of the FF devices.
The figure below provides a simplified overview of the mutually independent response of the
two Compact FF Links.
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Figure 8-2 Startup characteristics of the two Compact FF Links in redundancy mode
Operation of the bus link
8.4 Startup behavior
Compact FF Link
Operating Instructions, 03/2015, A5E35651552-AA 47