Failure Of The Primary Cpu - Siemens Simatic S7-1500R System Manual

Application planning
3.4 Redundancy scenarios
3.4.2

Failure of the primary CPU

Introduction
The following redundancy scenario describes the effects of a defective primary CPU.
Redundancy scenario
①
②
③
④
⑤
Figure 3-7
Sequence of events
1. The primary CPU of the redundant system fails in the RUN-Redundant system state.
2. The redundant system switches to the backup CPU. The backup CPU becomes the new
primary CPU. The redundant system switches to the RUN-Solo system state. You can
find additional information on the RUN-Solo system state in the section Operating and
system states (Page 197).
3. The new primary CPU exchanges process data with the IO devices.
4. The redundancy of the system is restricted. The restriction has no impact on the process.
If another system component or another network segment fails, this can result in the
failure of the S7-1500R/H redundant system. You can find additional information in the
section Failure scenarios (Page 72).
60
Primary CPU → failed
Backup CPU → becomes new primary CPU
PROFINET cable (redundancy connections, PROFINET ring)
IO device ET 200MP
IO device ET 200SP
Failure of the primary CPU (using S7-1500R as an example)
S7-1500R/H redundant system
System Manual, 10/2018, A5E41814787-AA