Siemens Simatic S7-1500R System Manual page 208

Preparing the SYNCUP system state
After SYNCUP starts, the CPUs prepare SYNCUP:
● The backup CPU switches to SYNCUP operating state and sends a status message to
the primary CPU.
● The primary CPU then switches from the RUN operating state to RUN-Syncup.
The current operating states are shown on the displays:
Table 9- 4
Sequence of the SYNCUP system state
The operating systems of the two CPUs run through SYNCUP in five phases:
● Copying the SIMATIC memory card
● Restart of the backup CPU
● Finishing tasks
● Copying the work memory
● Making up backup CPU lag
The display of the primary CPU shows you which phase the SYNCUP system state is
currently in.
The display of the backup CPU shows the RUN-Redundant during the phases
the "Connect..." system state is reached.
S7-1500R/H redundant system
System Manual, 10/2018, A5E41814787-AA
Preparing SYNCUP
Primary CPU
②
③
④
⑤
9.4 Operating and system states
①
Commissioning
Backup CPU
② ⑤
to until
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