Commissioning
9.4 Operating and system states
S7-1500R/H redundant system
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System Manual, 10/2018, A5E41814787-AA
9.4.5
RUN operating states
RUN operating states
The primary CPU goes through multiple operating states before reaching the RUN-
Redundant system state:
●
RUN
●
RUN-Syncup
●
RUN-Redundant
The backup CPU only has the RUN-Redundant operating state.
RUN operating state
In the RUN operating state, the primary CPU behaves just like an S7-1500 standard CPU. It
performs cyclic, time-driven and interrupt-driven program execution on its own.
Addresses that are in the "Automatic update" process image are automatically updated in
each program cycle. You can find more information in the section Process images and
process image partitions (Page 145).
Once the CPU has written the outputs and read the inputs, it executes the cyclic program
from the first instruction to the last instruction. Events with a higher priority such as hardware
interrupts, diagnostic interrupts and communication can interrupt the cyclic program flow and
prolong the cycle time.
If you have configured a minimum cycle time, the CPU does not terminate the cycle until
after this minimum cycle time has expired, even if the user program is completed sooner.
The operating system monitors the runtime of the cyclic program on the basis of a
configurable upper limit known as the maximum cycle time. You can restart this time
monitoring at any point in your program by calling the RE_TRIGR instruction.
If the cyclic program exceeds the cycle monitoring time, the timeout OB (OB 80) may be
started. You can find additional information in the section Start events (Page 153).
Points to note in the RUN operating state
In non-redundant operation, the CPUs are independent of each other. They can have
different projects.
Summary of Contents for Simatic S7-1500H
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