Connecta S7 300 with VB without OPC Server

[contope]

DEar All,

I´m trying to develope a little application (like a little Scada) inwich I have to communicate my PC with a PLC Siemens S7 300 via Visual Basic.
I understand I could use an OPC server but is out of muy budget. I read something from "DesertDog" saying it is possible to do it witho out any extra sofware.
COuld any body tell me somthing more about it?
thank you very much

 

[s7xp.com]

The only free driver for S7 communications is libnodave. All the orther drivers are not free. (Simatic Prodave, Deltalogic, MHJ, etc)

 

[S7Guy]

Assuming your S7-300 has an ethernet card, you wouldn't need a canned "driver". A cursory knowledge of sockets would be enough to communicate with VB directly.