Siemens SIMATIC S7-1500 System Manual page 119

Failure scenario
①
②
③
④
⑤
⑥
⑦
⑧
Figure 5-32 Failure of the two PROFINET lines in PROFINET ring 1 to the primary CPU.
Sequence of events
1. Both PROFINET lines in PROFINET ring 1 on the primary CPU fail. The redundant system
will not execute a primary-backup switchover. The redundant system will remain in the
RUN-Redundant system state.
2. The redundant system selects an alternative connection over the backup CPU and the
PROFINET ring 2. This allows the redundant system to reach the R1 devices again.
3. The redundancy of the system is restricted. The restriction has no effect on the process. If
another system component fails, the S7-1500R/H redundant system can fail as a result.
S7-1500R/H redundant system
System Manual, 11/2022, A5E41814787-AD
Primary CPU
Backup CPU
Two fiber-optic cables (redundancy connections)
PROFINET cable (PROFINET ring 1)
PROFINET cable (PROFINET ring 2)
PROFINET lines → interrupted
IO device ET 200SP HA
IO device ET 200SP
Application planning
5.4 Redundancy scenarios
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