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10.2
Possible hardware modifications
How is a hardware modification made?
If the hardware components concerned are suitable for unplugging or plugging in live, the
hardware modification can be carried out in redundant system state. However, the fault-
tolerant system must be switched temporarily to solo operation, because the download of a
modified hardware configuration in redundant system state would cause the fault-tolerant
system to stop. In solo operation, the process is then controlled by only one CPU while the
desired configuration changes are made to the other CPU.
Note
During a hardware modification, you can either remove or add modules. If you want to alter
your fault-tolerant system such that you remove modules and add others, you have to make
two hardware changes.
Note
Always download configuration changes to the CPU using the "Configure hardware"
function.
Synchronization link
Whenever you make hardware modifications, make sure that the synchronization link
between the two CPUs is established before you start or turn on the standby CPU. If the
power supply to the CPUs is on, the LEDs IFM1F and IFM2F that indicate errors on the
module interfaces on the two CPUs should go off.
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.
CPU 410-5H Process Automation/CPU 410 SMART
System Manual, 10/2013, A5E32631667-AA
System modifications during redundant operation
10.2 Possible hardware modifications
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