Siemens Simatic PCS 7 Function Manual page 240

Failure, switchover and reintegration of high availability components
7.13 Redundancy behavior of the PCS 7 OS, SIMATIC BATCH and SIMATIC Route Control servers
Order of the reactions
For OS server or com‐
puters with a combina‐
tion of server functions
● BATCH server
● OS server
● Route Control
Only for BATCH server
or for BATCH server in
combination with Route
Control server
Plant bus failure
● PCS 7 OS server:
So that the failure of the plant bus is recognized, the option "WinCC client switch in case
of a process connection error" has to be selected.
(Default setting: the option is selected)
● SIMATIC BATCH:
Failure of the plant bus is only relevant for SIMATIC BATCH if the batches are executed in
the automation system.
Order of the reactions
Only for BATCH serv‐
er or for BATCH serv‐
er in combination with
Route Control server
only for Route Control
server
For OS server or com‐
puters with a combi‐
nation of server func‐
tions
● BATCH server
● OS server
● Route Control
240
Failure at the master server (Serv‐
er_a)
server
If automatic restart is activated, it is executed on the server affected by the
Failure at the master server (Serv‐
er_a)
Standby server (Server_b) becomes
master;
Computer (server a) becomes stand‐
by
Standby server (Server_b) becomes
master
The computer becomes standby following reconnection to the plant bus.
server
Reactions
Process control message is output on the PCS 7 OS
failure.
The server is in "Standby" mode following restart.
Reactions
Computer switches to initialization or error status.
Process control message is output on the PCS 7 OS.
No isolation of the network adapter.
High Availability Process Control Systems (V9.0)
Failure at the standby server (Serv‐
er_b)
Failure at the standby server (Serv‐
er_b)
No redundancy switchover master re‐
mains master
No redundancy switchover master re‐
mains master
Function Manual, 05/2017, A5E39221836-AA