Commissioning
9.4 Operating and system states
S7-1500R/H redundant system
System Manual, 10/2018, A5E41814787-AA
219
②
POWER ON → STOP
Transition
Description
Effects
System state
transition
POWER ON → STOP
The redundant system switches to the STOP system state after switch-on if:
•
The mode selector is in the STOP position
or
•
The hardware configuration and program blocks are inconsistent
or
•
The startup type "No restart (remain in STOP)" is set
or
•
The startup type "Warm restart - Operating mode before POWER OFF" is
set and the redundant system was in STOP before POWER OFF.
The primary CPU
clears the non-
retentive memory and
resets the contents of
non-retentive data
blocks to the initial
values of the load
memory. Retentive
memory and retentive
DB contents are re-
tained.
Operating state
transitions
③
STOP → STARTUP
Transition
Description
Effects
System state
transition
STOP → STARTUP
The redundant system switches to the STARTUP system state if:
•
You set a CPU to RUN via the PG/PC or the display and the mode selec-
tor is set to RUN
or
•
You set the mode switch from STOP to RUN.
The CPU that you switch from STOP to RUN first remains/becomes the pri-
mary CPU. It switches to the STARTUP operating state and processes
startup OB 100.
The backup CPU remains in STOP.
The primary CPU
clears the non-
retentive memory and
resets the contents of
non-retentive data
blocks to the initial
values of the load
memory. Retentive
memory and retentive
DB contents are re-
tained.
Operating state
transition
STOP
→ STARTUP
After switch-on, the primary CPU switches to the STARTUP operating state
if:
•
The hardware configuration and program blocks are consistent
and
•
You set the CPU to RUN via the PG/PC or the display and the mode
selector is set to RUN
or
•
You set the mode switch from STOP to RUN.
Summary of Contents for Simatic S7-1500H
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