You are starting a brand-new, greenfield industrial automation project. For modern development, you should instead use official OPC UA .NET Standard libraries, which replace the old OpcNetApi.dll architecture entirely and provide a direct path forward into cloud integration, IoT, and cross-platform edge computing. Conclusion
using Opc; using Opc.Da; using OpcCom;
If your application cannot find the server, or throws a COMException (e.g., 80040154 Class not registered), you may be running a 64-bit application trying to use 32-bit components.
Using the wrong version of opcnetapidll can lead to the infamous "Interface not supported" error. opcnetapidll
If automatic registration fails, use RegSvr32:
The library supports the major specifications, including:
: It provides a unified set of .NET interfaces for accessing various OPC Classic specifications. Using the wrong version of opcnetapidll can lead
In industrial automation, older hardware often uses (Component Object Model) for communication. Since .NET languages like C# cannot interact with these COM interfaces directly, opcnetapi.dll acts as a bridge.
The safest method is to download the official from the OPC Foundation website (membership may be required) or from your automation vendor’s support portal.
Which are you targeting (e.g., OPC DA, OPC HDA)? You are starting a brand-new
: This library acts as the concrete implementation wrapper that explicitly translates the .NET API calls from OpcNetApi.dll into the underlying COM/DCOM calls required by OPC Classic servers.
Generate notifications through various channels such as email, SMS, or even triggering external applications/scripts. The notification should include relevant details about the condition met, including the node that triggered it and the value at the time of triggering.
