Hello, dear experts. 

I would like to start a discuss about the communication methods to communicate a Siemens S7 PLC with an High Level Application developed in Java, .Net or similar. 

The topic objective is a kind of brainstorm.

I will start

I like OPC communication, with OPC UA we can don't need DCOM and it's very easy to setup up and use, also it's easy to implement in PLC and there is official OPC Fundation API for .Net programming. Also there is a lot of connection APIs and plugins for another languages like Java.

Another alternative is TCP directly connection, sending and receiving TCP packages. I have no opinion about TCP communication. 

What about you, guys? 

Hello Allan;

You could start by having a look at this collection od Application Examples, showing how Java, C#, OPC UA can be used to connect a S7 CPU with an external PC Software.

 https://support.industry.siemens.com/cs/search?search=Java application&type=ExampleOfUse&lc=en-CA  

Hope this helps, 

Daniel Chartier