Siemens SIMATIC NET System Manual page 73

● Common data management
Data are only entered once and are available to the user across the entire factory (on the
PLC or computer end, in the visualization system or the distributed I/Os). If the data are
required at a different point, the software accesses the shared database. An elaborate
consistency check is not required. The "Industrial Datacenter" exists to this purpose.
WinCC is typically used here for process visualization.
● Modular system redundancy R1 in the backbone level
To achieve the highest possible reliability and availability, all devices and connections are
implemented redundantly on the backbone level. The connection to the enterprise
network is a redundant Layer 3 coupling via VRRP.
● Ring redundancy in the control network and in the factory network
The control and operation network is implemented as a redundant ring topology. Because
fiber-optic cables are used, these transmission paths are insensitive to electromagnetic
interference.
Requirements for industrial networks
The special demands placed on industrial networks compared to office networks result from
the structure of industrial plants and the requirements of manufacturing and process
automation that differ fundamentally from those of office applications. To ensure that
industrial networks can fulfil their function, the following criteria already have to be taken into
account during concept and planning:
● Industrial networks have to fulfil maximum requirements on the availability ("24/7"). Even
rare downtimes are not accepted. For this reason, it is often necessary to establish
redundant structures. The network components used have to support the corresponding
protocols and technologies.
● Depending on the application, the devices must be suitable for extreme ambient
conditions, such as shocks and high temperatures. In addition, further requirements for
explosion protection, suitability for outdoor conditions or special certifications for various
branches may also be necessary.
● The hardware equipment of the devices have to allow flexible adapting to changed
boundary conditions. Modular devices of the SCALANCE X series offer a high variability
of the port configuration. In addition, some devices can be extended by means of a port
extender. In the case of data-intensive applications the devices have to support Gigabit
Ethernet or 10 Gigabit Ethernet. Long transmission paths or special ambient conditions
require Interfaces for fiber-optic cables. Many SCALANCE devices use the C-PLUG/CLP
configuration memory, which simplifies the replacement of devices.
● The spatial extent of the nodes integrated into the network is of great importance. WLAN
is often used for mobile units. In addition to common antennas, the RCoax radiating cable
is an option for communication along predetermined paths or when radio coverage is not
possible or not to a sufficient extent. TeleControl and Teleservice can be used to access
distributed stations at remote locations, possibly also via mobile wireless networks with
UMTS or LTE.
Industrial Ethernet
System Manual, 09/2019, C79000-G8976-C242-10
Network structures and network configuration
2.1 Integration of a production network in an enterprise network
73