Failure and replacement of components during redundant operation
11.1 Failure and replacement of central components
CPU 410-5H Process Automation
System Manual, 09/2014, A5E31622160-AB
191
11.1.5
Failure and replacement of a synchronization module or fiber-optic cable
In this section, you will see three different error scenarios:
●
Failure of a synchronization module or fiber-optic cable
●
Successive failure of both synchronization modules or fiber-optic cables
●
Simultaneous failure of both fiber-optic cables
The CPU indicates by means of LEDs and diagnostics whether the lower or upper redundant
link has failed. After the defective parts (fiber-optic cable or synchronization module) have
been replaced, LEDs IFM1F and IFM2F must go out.
If one of the IFM LEDs continues to be lit even after you have replaced the relevant
synchronization modules, the synchronization cables and even the standby CPU, there is an
error in the master CPU. In this case, you can, however, switch to the standby CPU by
selecting the "via only one intact redundancy link" option in the "Switch" STEP 7 dialog box.
Starting situation
Failure
How does the system react?
Failure of a fiber-optic cable or synchronization
module:
The S7-400H is in redundant system mode and a
fiber-optic cable or synchronization module fails.
See also chapter Synchronization modules for
the CPU 410-5H (Page 201).
•
The master CPU reports the event in the
diagnostic buffer and with OB 72 of OB 82.
•
The standby CPU switches to ERROR-
SEARCH operating state for a few minutes. If
the error is eliminated during this time, the re-
serve CPU switches to redundant system
mode, otherwise it switches to STOP.
•
One of the two LEDs Link1 OK or Link2 OK is
lit
One of the two LEDs IFM1F or IFM2F is lit
Procedure
Follow the steps below to replace a fiber-optic cable:
Step
What to do?
How does the system react?
1
Look for the cause of the error along the path
for which the IFMxF LEDs are lit on both
CPUs:
IFM1F: Top sync modules in CPU rack 0 or
rack1 or the corresponding synchronization
cable.
IFM2F: Bottom sync modules in CPU rack 0
or rack1 or the corresponding synchroniza-
tion cable.
First, check the fiber-optic cable.
–
2
If the fiber-optic cable is defective, replace it. The IFMxF LEDs on both CPUs go out.