Using a LabWindows/CVI Program as an OPC Server Through the NI Network Variable EnginePrimary Software: LabWindows/CVI Development Systems>>Full Development SystemPrimary Software Version: 8.5 Primary Software Fixed Version: N/A Secondary Software: N/A
Problem: I would like to use a LabWindows/CVI program as an OPC server through the NI Network Variable Engine. How do I accomplish this? Solution: As of LabWindows/CVI 8.1 and newer, the Network Variable Engine is fully accessible by CVI, and it should be automatically installed when you install LabWindows/CVI. You can verify that the Network Variable Engine is installed by going to Start » Programs » National Instruments » Variable Manager. If this Start Menu entry exists, the Network Variable Engine is installed. In order to publish a variable to the Network Variable Engine, you can use the Network Variable Library that is distributed with LabWindows/CVI. An example of this can be found in LabWindows/CVI by going to Help » Find Examples, and then select Networking » Network Variable » NVPublisher.cws. In this example, you will need to manually enter the name of the variable that you wanted to publish, for example: \\localhost\myProcess\TestVariable. This will automatically create and publish this variable. You can then use the LabVIEW OPC Client examples from another machine to read data from the CVI OPC Server. Additionally, you will need to verify that the OPC server is accessible from other computers by configuring any firewalls that may exists on both the client and the server machines. There is also some additional configuration that may be needed in order to set proper DCOM access for remote OPC Servers when using NI OPC Clients. A list of resources for configuring these settings is included in the Related Links section at the end of this article. Related Links:
Developer Zone Tutorial: General DCOM Configurations for Windows 95/98/Me Attachments:
Report Date: 03/12/2008 Last Updated: 03/17/2008 Document ID: 4JB9GOPO |
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