Replacement of failed components during redundant operation   
13.1 Replacement of central components 
  CPU 410 Process Automation/CPU 410 SMART 
224  System Manual, 05/2017, A5E31622160-AC 
 
Caution when replacing a CPU 
If you reuse a CPU that has previously been used at a different location, ensure that the 
contents backed up in the load memory cannot pose a hazard at the new point of use. 
Reset the CPU to factory settings if its previous use is unknown. 
See Resetting the CPU 410 to delivery condition (reset to factory setting) (Page 142) 
 
 
Note 
Replacing an SEC 
You can replace an SEC by following the same procedure as described above. Here you do 
not replace the CPU in step 2, but replace the SEC with an SEC of the same size and then 
reinstall the CPU.
 
Follow the steps below to 
: 
 
How does the system react? 
1  Turn off the power supply module. 
•  The entire subsystem is switched off 
(system operates in single mode). 
2  Replace the CPU. Make sure the rack num-
ber is set correctly on the CPU. 
– 
Insert the synchronization modules. 
4  Plug in the fiber-optic cable connections of 
the synchronization modules. 
– 
5  Switch the power supply module on again. 
•  CPU runs the self-tests and changes to 
STOP. 
6  Perform a CPU memory reset on the re-
placed CPU. 
– 
7  Start the replaced CPU (for example, STOP-
RUN or Start using the PG). 
•  The CPU performs an automatic LINK-
UP and UPDATE. 
• 
The CPU changes to RUN and operates 
as the standby CPU.