Siemens SIMATIC S7-1500 System Manual page 391

Commissioning
12.4 Operating and system states
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 12- 5
Sequence of the SYNCUP system state
The operating systems of the two CPUs run through SYNCUP in five phases:
• Copying the SIMATIC Memory Card ①
• Restart of the backup CPU ②
• Finishing tasks ③
• Copying the work memory ④
• Making up backup CPU lag ⑤
The display of the primary CPU shows you the current phase of the SYNCUP system state.
The display of the backup CPU shows "Connect..." state during the phases ② to ⑤ until the
RUN-Redundant system state is reached.
390
Preparing SYNCUP
Primary CPU Backup CPU
S7-1500R/H redundant system
System Manual, 01/2024, A5E41814787-AF