Redundancy Behavior Of The Pcs 7 Os, Simatic Batch And Simatic Route Control Servers - Siemens Simatic PCS 7 Function Manual

7.13 Redundancy behavior of the PCS 7 OS, SIMATIC BATCH and SIMATIC Route Control servers

7.13 Redundancy behavior of the PCS 7 OS, SIMATIC BATCH and
SIMATIC Route Control servers
Error-free System
A redundant server pair is considered to be fault-free when the following conditions are met:
● Both servers are in process mode (master or standby).
● All process mode data are synchronized between the servers.
Failure of a server computer (computer of a server pair)
Order of the reactions
For computers with a
server function or
computers with a
combination of server
functions
● BATCH server
● OS server
● Route Control
Failure of the terminal bus
Order of the reactions
Only for BATCH server
or for BATCH server in
combination with Route
Control server
Only for BATCH server
or for BATCH server in
combination with Route
Control server
For computers with a
server function or com‐
puters with a combina‐
tion of server functions
● BATCH server
● OS server
● Route Control
High Availability Process Control Systems (V9.0)
Function Manual, 05/2017, A5E39221836-AA
Failure, switchover and reintegration of high availability components
Failure at the master server (Serv‐
er_a power off)
Standby server (Server_b) becomes
master
server
Failure at the master server (Serv‐
er_a)
The dialog "Restart request" appears at the server affected by the failure.
Standby server (Server_b) be‐
comes master
server
Network adapter for terminal bus and redundant link are deactivated.
Reactions
Failure at the standby server (Server_b
power off)
No redundancy switchover master re‐
mains master
Reactions
Failure at the standby server (Serv‐
er_b)
No redundancy switchover master re‐
mains master
239