Quote Originally Posted by chris128 View Post
...I mean is there any way I could test it in the same way you are testing it? Does it require any special equipment or anything like that?
You can get an OPC-DA DLL from OPC Foundation, Kepware, or RSLinx. The file you need on your system is something like OPCDAAuto.DLL, kepopcdaauto.dll, or RSopcdaauto.dll.

Once installed on your system, you can instantiate the appropriate objects with which you can examine actual OPC-DA Servers, if you have any installed on your system.

Iconics has a free OPC Simulator and TopServer has a free OPC Simulator.

Quote Originally Posted by chris128 View Post
...What exactly does this OPC server thing do?
Think of an OPC-DA server like a printer driver, only an industry standard printer driver. In fact, it is exactly an industry standard device driver. If you make a hardware device, you can also make a software OPC-DA driver to go along with it.

It is widely adopted because many vendors make useful OPC-DA clients, which all know how to talk to any OPC-DA server.