Siemens Simatic S7-1500R System Manual page 228

(1) Primary CPU switches to the RUN operating state
Figure 9-11 Primary CPU switches to the RUN operating state
Table 9- 13 Response to loss of redundancy: Primary CPU switches to RUN
No. in Primary CPU
diagram
Initial situation: The S7-1500R/H redundant system is in the RUN-Redundant system state.
The backup CPU fails because of a hardware defect.
①
The CPU switches from RUN-
Redundant to RUN. The CPU be-
haves like a standard CPU and
continues to process the user pro-
gram.
Error elimination procedure for redundant operation
1. Eliminate the error.
2. Switch the backup CPU to the RUN operating state.
The backup CPU switches from the STOP operating state to the SYNCUP operating state.
Synchronization starts as detailed in the section SYNCUP system state (Page 205).
S7-1500R/H redundant system
System Manual, 10/2018, A5E41814787-AA
System state
RUN-Redundant → RUN-Solo
Commissioning
9.4 Operating and system states
Backup CPU
Following the error, the CPU switches
from the RUN-Redundant operating state
to STOP or POWER OFF.
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