Siemens Simatic S7-1500R System Manual page 66

Sequence of events
1. A defective or disconnected PROFINET cable interrupts the PROFINET ring of the
redundant system.
2. The redundant system remains in the RUN-Redundant system state: The primary and
backup CPUs remain in the RUN-Redundant operating state.
3. The redundant system selects an alternative connection over the backup CPU. This
allows the redundant system to access all IO devices in the PROFINET ring again.
4. The redundancy of the system is restricted. The restriction has no effect on the process.
In the following examples, other components also fail in the redundancy scenario
described. The result is a failure scenario:
If another system component or another network segment fails, this can result in the
failure of the S7-1500R/H redundant system.
– If the primary CPU fails in addition to a PROFINET cable, the backup CPU switches to
– If the PROFINET cable is also interrupted at another point, IO devices in the
– You can find additional information in the section Failure scenarios (Page 72).
Diagnostics
System state, operating states and error displays after the failure of the PROFINET cable:
● Redundant system → RUN-Redundant system state
● Primary CPU → RUN-Redundant operating state
– MAINT LED → yellow light: The PROFINET ring is open. There is only one redundancy
● Backup CPU → RUN-Redundant operating state
– MAINT LED → yellow light: The PROFINET ring is open. There is only one redundancy
Note
To get detailed diagnostics information, evaluate the diagnostics buffer.
Solution
Replace the defective PROFINET cable or reconnect the disconnected PROFINET cable.
You can find additional information on the procedure in the section Replacing defective
PROFINET cables.
S7-1500R/H redundant system
System Manual, 10/2018, A5E41814787-AA
the STOP operating state.
PROFINET ring may fail depending on the location of the interruption.
connection remaining in the redundant system.
connection remaining in the redundant system.
Application planning
3.4 Redundancy scenarios
65