Operating And System States; Overview - Siemens SIMATIC S7-1500 System Manual

Commissioning

12.4 Operating and system states

12.4 Operating and system states
12.4.1

Overview

Operating states
Operating states describe the behavior of an individual CPU at a specific time. Knowledge of
the operating states of the CPUs is useful for programming startup, testing and error
diagnostics. The status LEDs on the front of the CPU and the CPU display indicate the current
operating state.
Like standard S7-1500 CPUs, the S7-1500R/H-CPUs have the operating states STOP, STARTUP
and RUN. For operation as redundant system, one of the two CPUs can take on an additional
operating state, SYNCUP, for synchronizing the two subsystems. The RUN operating mode is
divided into the following states for redundant systems:
• RUN
• RUN-Syncup
• RUN-Redundant.
System states
The system states enable the direct assessment of the behavior of a redundant system. They
result from the combination of the operating states of the individual CPUs.
• STOP
• STARTUP
• RUN-Solo
• SYNCUP
• RUN-Redundant
Event-controlled synchronization
Event-controlled synchronization ensures that both CPUs in a redundant system can operate
redundantly (RUN-Redundant system state).
For all events that could result in different internal subsystem states, the operating system
automatically synchronizes the data of the primary and backup CPU.
Primary and backup CPU are, for example, synchronized in the event of:
• Direct access to the IO devices
• Events that interrupt cyclic program execution
• Updates to user times, for example S7 timer
• Updates to the process image
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S7-1500R/H redundant system
System Manual, 01/2024, A5E41814787-AF