Siemens SIMATIC S7-1500 System Manual page 397

Commissioning
12.4 Operating and system states
Effects of the SYNCUP system state
In SYNCUP, there are different effects on the execution of the user program and
communication functions. The effects are set out in the table below.
Table 12- 11 Properties of SYNCUP
Procedure
Processing of the user program on the
primary CPU
Deleting, loading, generating and com-
pressing blocks
Processing communication functions
PG/PC operation
Test and commissioning functions, for
example "Monitor and modify tags",
"Monitoring (on/off)".
Connection handling in the primary CPU
Connection handling in the backup CPU
Diagnostics alarms
Data logging, recipes, and user files
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Effects during the SYNCUP system state
All priority classes (OBs) are processed. Processing is delayed during the snap-
shot. After the snapshot, the primary CPU immediately resumes user program
execution and asynchronous instructions are started.
Blocks cannot be deleted, loaded, generated or compressed.
The execution of parts of functions is limited and delayed. The system makes up
the delays in all functions after SYNCUP.
Depending on the SYNCUP phase, online connections from the PG/PC to the CPU
may not be possible. Existing connections are aborted.
Depending on the SYNCUP phase, no test and commissioning functions may be
possible.
All communication connections are initially aborted.
After the snapshot, the primary CPU re-establishes communication connections
with active connection establishment. Note that the CPU takes some time to re-
establish the communication connections.
The CPU re-establishes connection endpoints for communication connections
with passive connection setup.
All communication connections are initially aborted.
The backup CPU establishes connections (ARs) to the IO devices (only with sys-
tem redundancy S2 and R1).
The communication connections on the backup CPU become available during
the backup CPU catch-up process. The communication connections of the CPs
on the rail of the backup CPU are only available in the RUN-Redundant system
status.
Diagnostic alarms can be delayed during the SYNCUP system state. The OB 82
reports delayed diagnostics interrupts.
If diagnostic alarms occur during the "Making up backup CPU lag" phase, the
diagnostic alarms can prolong this phase. You can find more information in the
Basics of program execution (Page 323) section.
During SYNCUP, all original data logs, recipes, and user files on the backup CPU
are deleted: The files for Data Logs, Recipes and UserFiles are transferred from
the primary CPU to the backup CPU during SYNCUP.
The duration of the SYNCUP depends on the size of the \DataLogs, \Recipes, and
\UserFiles folders. There is a linear relationship in this case: The more data has
to be synchronized, the longer the system state SYNCUP takes.
During SYNCUP, the \DataLogs, \Recipes, and \UserFiles folders on the primary
CPU are deleted. This means that neither read nor write access is possible. The
corresponding instructions (e.g. FileWriteC) are executed with a delay during
this phase. To prevent data loss, you must implement a queue function in the
following cases:
• With cyclic jobs
• If it is to be expected that the delay time of the relevant instruction at
SYNCUP is higher than the cycle time of the associated job.
S7-1500R/H redundant system
System Manual, 01/2024, A5E41814787-AF