Link-Up And Update Sequence - Siemens SIMATIC PCS 7 CPU 410-5H System Manual

15.12

Link-up and update sequence

There are two types of link-up and update operation:
● Within a "normal" link-up and update operation, the fault-tolerant system will change over
from solo operation to redundant system state. The two CPUs then process the same
program synchronously.
● When a link up and update operation takes place with master/standby changeover, the
second CPU with modified components can assume control over the process. Either the
hardware configuration or the operating system may have been modified.
In order to return to redundant system state, a "normal" link-up and update operation
must be performed subsequently.
How to start the link-up and update operation?
Initial situation: Solo operation, i.e., only one of the CPUs of a fault-tolerant system
connected via fiber-optic cables is in RUN operating state.
You can initiate the link-up and update operation for achieving the redundant system state as
follows:
● POWER ON the standby if prior to POWER OFF the CPU was not in STOP operating
state.
● Operator input on the PG/ES.
You can only start a link-up and update operation with master/standby changeover by an
operator input on the PG/ES.
Note
If a link-up and update operation is interrupted on the standby CPU (for example due to
POWER OFF, STOP), this may cause data inconsistency and lead to a memory reset
request on this CPU.
The link-up and update functions are possible again after a memory reset on the standby.
CPU 410-5H Process Automation
System Manual, 09/2014, A5E31622160-AB
Supplementary information
15.12 Link-up and update sequence
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