Siemens SICAM AK, Manual

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Redundancy via SCA-RS
34
Unrestricted SICAM RTUs, SICAM AK Redundancy
Edition 10.2016, DC2-026-2.07
•
In the OPM system technique select Redundancy buffer under the node Redundancy
below the M-CPU:
The redundancy buffer is used to avoid the loss of data during the occurrence of an
error/failure until the redundancy switchover is complete.
Column name/
Parameter
Description/Value Comment
Global enabling disabled
enabled
Buffer size Maximum number of process information
items, that can also be stored in the
Buffer
time .
1-32000
Buffer time Maximum time, during which the process
information items should also be stored. 1-255 Seconds
The parameter group Redundancy buffer is also available on the CP-2017/PCCX25.
The following parameter groups are identical with those on the C:CPU:
•
Address of the redundant BSE
•
Synchronization parameters
•
Singular Ax-PEs
Refer to section 1.4, Parameter Setting of the CP-2017/PCCX25 .
1.2.3.2 Automatic Voting
Every system has 15 priority levels (0 to 14), whereby 14 is the highest level.
The Voter evaluates both redundancy systems based on the defined number and the priority
levels. The Voter interprets the subsystem with the higher priorities as the faulty one and
switches over to the other system.
You define the criteria for a Voter switchover!
(The priorities can also be defined with the help of CAEx plus , according to the requirements
of your total system.)
The Voter compares the statuses of both systems, by starting from the highest priority
level 14. If both systems have the same status, the Voter compares both systems based on
the next lower priority level.