Guide in understanding OPC concepts

Question

im trying to learn OPC for a project we are developing,

i thought i understood a couple of things but a discussion with a colleague showed me otherwise

So, please correct me if wrong on these terms/concepts:

• OPC is basically a protocol that allows devices to talk using the same language, in the same way we have http, tcp and all others.

• When i say OPC Server, i mean a computer/program connected to a specified device, with the proper driver that exposes access to said device via the OPC protocol;

• When i say OPC Client, i mean a device/software that can connect to that server or to the original device (aka the one that produces the data) to read and and write some data

• OPC UA allows me to connect to legacy devices that are using the old opc (the dcom/com version) and future devices

• OPC allows for auto-configuration of devices, meaning i can get a list of what info the device provides, and configure them according to what i want

Answer 1

For the most part, you seem to have stated things correctly.

The last bit about "auto-configuration" seems a bit optimistic, unless I'm taking you too literally. There's nothing automated about it. You can retrieve lists of servers, nodes, topics, etc. But those are only for convenience.

Have you found the OPC Foundation website? A wealth of information and they provide the libraries.