Siemens SINUMERIK 840D sl Equipment Manual page 37

Fundamentals
The system network for SINUMERIK solution line is structured as a star topology with a central
Ethernet switch, to which all Ethernet-based components of the system are connected.
For an NCU the connection is executed via the X120 Ethernet socket, for PCU it is executed
via the "Ethernet 2" connection. There is no default for all other components with two
Ethernet connections. These components have an internal 2-port switch and may be used to
connect an additional operator component. Thus in this case there can be deviation from the
strict star topology.
System network
In the system network the IP address 192.168.214.xxx with subnet mask 255.255.255.0 is pre-
selected. Here there is precisely one DHCP server with DNS that can run on one NCU or one PCU.
The server ensures assignment of IP addresses to the Ethernet components in the system
network (DHCP clients) from a specified address band.
The following rules apply for assignment of IP addresses in the system network:
• For all NCUs and PCUs the commissioning engineer assigns fixed IP addresses in the
associated address bands, as well as appropriate computer names (host names). All other
(operator) components are automatically assigned an IP address from the DHCP server. Its
name is generated automatically (for MCP, MPP, HT 8), or is entered at commissioning (TCU).
• If there are multiple NCU and/or PCU in the system network the system automatically
(depending on the start-up sequence) specifies the DHCP server and automatically ensures
synchronization of all necessary data so that the next time the system boots any other NCU
or PCU could take on the role of DHCP server. However it is a good idea to specify a DHCP
master. This is an NCU or PCU in the system network that is available at each system boot and
which regularly takes over the task of the DHCP server and DNS server.
Synchronization of data takes place in any event so that any other NCU or PCU can take over
this task. All non-master NCU / PCU wait in the system boot an adjustable length of time for
availability of the master.
Note
In a system network, on a boot server respectively - i.e. the NCU or PCU which accommodates
the active DHCP server - a maximum of 30 operator stations may be operated simultaneously
with a TCU.
A maximum of 10 operator stations with a TCU may connect up simultaneously with the
same HMI application when powering up.
Connection to a company network
Each NCU can be connected via X130, and each PCU can be connected via "Ethernet 1" to the
company network. The company network is used to exchange operating software with servers
or to execute part-programs directly from servers in the company network. Company network
and system network should always be logically and also physically separated.
Handheld Terminal HT 8
Equipment Manual, 02/2024, A5E52918633B AA
General information and networking
4.3 Networking
37