Assigning Internet Protocol (Ip) Addresses; Assigning Ip Addresses To Programming And Network Devices - Siemens SIMATIC S7 System Manual

5.6.4

Assigning Internet Protocol (IP) addresses

5.6.4.1

Assigning IP addresses to programming and network devices

If your programming device is using an on-board adapter card connected to your plant LAN
(and possibly the world-wide web), the IP Address Network ID and subnet mask of your CPU
and the programming device's on-board adapter card must be exactly the same. The
Network ID is the first part of the IP address (first three octets) (for example, 211.154.184.16)
that determines what IP network you are on. The subnet mask normally has a value of
255.255.255.0; however, since your computer is on a plant LAN, the subnet mask may have
various values (for example, 255.255.254.0) in order to set up unique subnets. The subnet
mask, when combined with the device IP address in a mathematical AND operation, defines
the boundaries of an IP subnet.
Note
In a world-wide web scenario, where your programming devices, network devices, and IP
routers will communicate with the world, unique IP addresses must be assigned to avoid
conflict with other network users. Contact your company IT department personnel, who are
familiar with your plant networks, for assignment of your IP addresses.
If your programming device is using an Ethernet-to-USB adapter card connected to an
isolated network, the IP Address Network ID and subnet mask of your CPU and the
programming device's Ethernet-to-USB adapter card must be exactly the same. The Network
ID is the first part of the IP address (first three octets) (for example, 211.154.184.16) that
determines what IP network you are on. The subnet mask normally has a value of
255.255.255.0. The subnet mask, when combined with the device IP address in a
mathematical AND operation, defines the boundaries of an IP subnet.
Note
An Ethernet-to-USB adapter card is useful when you do not want your CPU on your
company LAN. During initial testing or commissioning tests, this arrangement is particularly
useful.
S7-1200 Programmable controller
System Manual, 11/2011, A5E02486680-05
98BDevice configuration
5.6 Configuring the CPU for communication
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