How to connect a device to Reliance via an OPC server

OPC is an open standard that enables client applications to communicate with HW devices in a unified way. The communication is based on a client/server architecture. An OPC server provides the communication with a HW device and represents a data source for OPC clients (e.g. Reliance).

To connect a device to Reliance via an OPC server, please follow these steps:

• Obtain and install an OPC server. OPC servers are usually provided by HW device manufacturers or specialized third-party companies. It is also possible to download various OPC software from OPC Foundation.


• Run the OPC server, create and register the so-called configuration. A configuration includes a list of devices along with communication options and a list of variables (the so-called OPC items) whose values are to be read from the devices. This configuration must be saved and registered in order to be available after starting up the OPC server.



Note: The way of creating, saving and registering a configuration is OPC server-specific.





• In a visualization project, add a new device of type OPC via the Device Manager (Reliance Design | Device Manager). For the OPC device, configure the "OPC server Prog ID" property by selecting the respective OPC server from the list of installed OPC servers.




• Select the "Variables" folder under the OPC device and add a new OPC group by choosing the "New OPC group" command from the pop-up menu. Select the new OPC group and choose the "Import from OPC server" command. This will bring up the "Import variables from OPC server" dialog populated with the OPC server configuration.





In the "Import variables from OPC server" dialog, drag and drop selected OPC items to the bottom pane.





• Connect the OPC device to a computer via the Project Structure Manager (Reliance Design | Project Structure Manager) by adding a link to the device to the "Devices" folder under the computer.


• Run the project by choosing the "Start" command (Reliance Design | Runtime | Start). While starting the project, the runtime software should launch the OPC server and begin to communicate with it.

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