Siemens SIMATIC ET 200AL, System Manual

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Glossary
Communication
Function Manual, 05/2021, A5E03735815-AJ
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SNMP
S imple N etwork M anagement P rotocol, uses the wireless UDP transport protocol. SNMP
works in much the same way as the client/server model. The SNMP manager monitors the
network nodes. The SNMP agents collect the various network-specific information in the
individual network nodes and makes this information available in a structured form in the
MIB ( M anagement I nformation B ase). This information allows a network management
system to run detailed network diagnostics.
Subnet
Part of a network whose parameters must be matched up on the devices (for example in
PROFINET). A subnet includes the bus components and all connected stations. Subnets can be
linked together, for example using gateways or routers to form one network.
Switch
Network components used to connect several terminal devices or network segments in a
local network (LAN).
Switched communication
In addition to the device IP addresses of the CPUs, the redundant system S7-1500R/H
supports system IP addresses:
•
System IP address for the X1 PROFINET interfaces of the two CPUs (system IP address X1)
• System IP address for the X2 PROFINET interfaces of the two CPUs (system IP address X2)
You use the system IP addresses for communication with other devices (for example, HMI
devices, CPUs, PG/PC). The devices always communicate over the system IP address with the
primary CPU of the redundant system. This ensures that the communication partner can
communicate with the new primary CPU (previously backup CPU) in the RUN-Solo system
state after failure of the original primary CPU in redundant operation.
System states
The system states of the redundant system S7-1500R/H result from the operating states of
the primary and backup CPUs. The term system state is used as a simplified expression that
refers to the operating states that occur simultaneously on both CPUs. The redundant system
S7-1500R/H has the system states STOP, STARTUP, RUN-Solo, SYNCUP and RUN-Redundant.
TCP/IP
T ransmission C ontrol P rotocol / I nternet P rotocol, connection-oriented network protocol,
generally recognized standard for data exchange in heterogeneous networks.
Time-of-day synchronization
Capability of transferring a standard system time from a single source to all devices in the
system so that their clocks can be set according to the standard time.