Siemens SIMATIC PCS 7 CPU 410-5H System Manual page 192

Failure and replacement of components during redundant operation
11.1 Failure and replacement of central components
Follow the steps below to replace a synchronization module:
Step
1
2
3
Starting situation
Failure
Simultaneous failure of both fiber-optic cables
The S7-400H is in redundant system mode and
both fiber-optic cables fail.
Procedure
The described double fault results in loss of redundancy and partial or complete failure of
switched DP or PN I/O. In this event proceed as follows:
Step
1
2
3
4
192
What to do?
Replace the synchronization module on the
CPU on which the LED Linkx-OK is still lit.
Plug in the fiber-optic cable connections of
the synchronization modules.
Start the standby CPU.
What to do?
Switch off one subsystem.
Replace the faulty components.
Turn the subsystem back on.
Start the CPU.
How does the system react?
–
The LEDs IFMxF go out.
•
If the LED should not go out, you must
replace the synchronization module on
the other CPU.
Both CPUs report the event in the diag-
•
nostic buffer
The system status now changes to Redun-
dant mode.
How does the system react?
Both CPUs report the event in the diagnostic
•
buffer and via OB 72.
Both CPUs become the master CPU and
•
remain in RUN mode.
The LEDs IFM1F and IFM2F are lit on both
•
CPUs.
How does the system react?
–
–
LEDs IFM1F and IFMF2F go off. The
•
LED MSTR of the switched on subsys-
tem goes out.
The CPU performs an automatic LINK-
•
UP and UPDATE.
The CPU changes to RUN (redundant
•
system mode) and operates as reserve
CPU.
CPU 410-5H Process Automation
System Manual, 09/2014, A5E31622160-AB