Profinet and TCP on S7-400

well, in my opinion you are able to run PROFINET IO and TCP Communication on the PN Interface at the same time, but you will have to be aware that the performance of the PROFINET IO will suffer a bit. Theses Interfaces can handle a certain amount of Telegrams a second... but not endless.

If you want to configure a TCP Connection with the PN Interface you can not work just like with the CP Interface, e.g. NetPro will not work.
The Connections will be configured in a DB that has to be loaded, the Communication itself has to be established, handled and finished by you in your S7 Program.
To get the DB you can use the Open Communication Wizard.

Best regards