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Commissioning
9.4 Operating and system states
S7-1500R/H redundant system
226
System Manual, 10/2018, A5E41814787-AA
9.4.8
Loss of redundancy
Introduction
The following section explains in more detail the system and operating state transitions
⑦
,
RUN-
Redundant → RUN
-Solo and RUN-
state transitions (Page 217) section.
Response
Loss of redundancy means:
●
The redundant system switches from the RUN-Redundant system state to the RUN-Solo
system state.
●
The primary CPU switches from the RUN-Redundant operating state to RUN (1)
or
●
Primary-backup switchover: The backup CPU becomes the primary CPU and switches
from the RUN-Redundant operating state to RUN (2).
The primary CPU continues to execute the user program in the RUN operating state and
exchanges process data with the IO devices.
Causes of redundancy loss
The redundant system switches from the RUN-Redundant system state to RUN-Solo if:
●
You POWER OFF one of the CPUs.
●
You set one of the two CPUs to STOP with the PG/PC, the display or the mode selector.
●
A CPU detects an error that prevents continued processing, for example:
–
Failure of a CPU, for example as a result of a hardware defect.
–
Cycle time exceeded
Содержание Simatic S7-1500H
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