How It Works

How the OPC DA Server Toolkit Works

The OPC DA Server Toolkit is a DLL that you link with your application. Your application may be a new or existing application to which you want to add OPC DA compliant interfaces.

The DLL exposes a simple set of objects and API calls behind which are aggregated all the COM interfaces and OPC object resources required to manage OPC DA client connections.

The diagram illustrates the toolkit objects (in blue) used by a developer. The OPC DA server objects (in red) are automatically managed by the toolkit. You write the code that integrates the toolkit callback object with your system’s interfaces and that creates a shared data cache.

What the Developer Does

As the developer, you work with the toolkit objects and API calls to provide the following.

	Manage (create / delete) items in the data cache using the a base class supplied by the toolkit. Your cache can be static or dynamic.
	Whenever the underlying value or quality for a cache item changes, update that information in the cache.
	When an OPC client requests or modifies a specific update rate for an OPC group, verify your underlying system can satisfy this request, otherwise return a rate that can be supported.
	Manage the namespace of your server in support of OPC browsing. The toolkit provides sample code and helper classes to assist with implementation of browse support. The helper classes work in conjunction with the CTKBrowser object exposed by the toolkit.
	When requested by the toolkit, perform device reads or device writes.

What the Toolkit Does For Your Application

Here is a summary of what the toolkit does for your application.

	Manages all OPC DA client connections for your server.
	Efficiently creates, manages, and destroys OPC DA COM objects as required.
	Transparently manages OPC groups (and the OPC items therein) created by an OPC DA client.
	Synchronous and asynchronous reads from the data cache are automatically handled by the toolkit.

More Details

Read the data sheet for more details. Also, download the demonstration software for the OPC DA Server Toolkit. The demo contains the complete server toolkit, including a Reference Manual and a sample implementation (with source code). You can even write your own server. Click here for the demo.