Siemens SICAM AK Manual page 18

Redundancy via SCA-RS
Example for CPU-Redundancy:
FUD is running, for instance, on both C-CPUs of the AU. Synchronization mode is HSL with
singular Ax-PEs.
Example for AE-redundancy with singular AX-PE-Bus.
Periodical data points from the PEs are detected automatically over the HSL and used by the
passive CPU.
Spontaneous data points are copied from the active CPU to the passive CPU.
If the communication between the passive BSE and the PE is interrupted, no further periodical
data points are updated on this BSE.
Spontaneous data points are flagged as NT (not topical) and also not updated.
Following restoration of the communication the periodical data points are updated
immediately.
If the FUD has been changed during the communication failure between the passive BSE and
the PE, the status of the CAEx plus application is not identical on both BSEs.
The synchronization of the spontaneous data points must take place by copying the process
image, see parameter Red_Sync Org_Abb, in section
2017/PCCX25.
18
1.4, Parameter Setting of the CP-
Unrestricted SICAM RTUs, SICAM AK Redundancy
Edition 10.2016, DC2-026-2.07