The OpenWMS.org OPCUA Driver component is designed and realised to work with OPCUA compliant counterparts acting as an OPCUA Server.

# Architecture

The OPCUA architecture follows the traditional Client-Server Architecture (CSA) where a client connects to a server in order to exchange messages.

## Connectivity

With OPCUA two connectivity methods can be used basically. Either direct point-to-point or through a [discovery service](https://reference.opcfoundation.org/Core/Part4/v105/docs/5.4).

### Point-to-Point Connection (PtP)

### Discovery Service Connection (DSC)

Read more information about the OPCUA Discovery Service here:

*   [https://reference.opcfoundation.org/Core/Part4/v105/docs/5.4](https://reference.opcfoundation.org/Core/Part4/v105/docs/5.4)

## Protocol

In the current version three protocols can be used for transferring messages: TCP/IP Sockets, HTTPS, WebSockets

# Client Operations

A client, in the context of projects realised with OpenWMS.org, is always the OpenWMS.org application. The OPCUA server is either the direct IPC/PLC or a middleware (so called DACO - DAta COncentrator). Defined by the OPCUA specification a client has four options to communicate to a server:

*   READ
*   WRITE
*   SUBSCRIBE
*   EXECUTE