Siemens S7-1200 System Manual page 546

Communication
10.2 PROFINET
The station name is subject to the following limitations:
● A name component within the station name, i.e., a character string between two dots,
must not exceed 63 characters.
● No special characters such as umlauts, brackets, underscore, slash, blank space, etc.
The only special character permitted is the dash.
● The station name must not begin or end with the "-" character.
● The station name must not begin with a number.
● The station name form n.n.n.n (n = 0, ... 999) is not permitted.
● The station name must not begin with the string "port-xyz" or "port-xyz-abcde" (a, b, c, d,
e, x, y, z = 0, ... 9).
Note
You can also create an ARRAY "nos" that is shorter then 240 bytes, but not less than 2
bytes. In this case, you must adjust the "len" (length of subfield) tag accordingly.
How to change IP parameters
In the following example, in the "addr" subfield, the "InterfaceAddress" (IP address),
"SubnetMask", and "DefaultRouter" (IP router) are changed. In the CPU "Properties",
"Ethernet address" page, the "Set IP address using a different method" radio button must be
clicked to enable you to change the IP address using the "T_CONFIG" instruction after the
program is downloaded.
546
S7-1200 Programmable controller
System Manual, 03/2014, A5E02486680-AG