Some years ago, I had to implement an OPC UA Client and server with .NET. Here are some steps from my journey that may help you:
- Nuget packages available are not working as expected. Use the source code directly from GitHub.
- The first test should be done using the samples available on the GitHub project. There are both server and client samples.
- When you try with a PLC, start with no security.
- Use the sample OPC UA client from GitHub to read the PLC node, just to understand how to compose the node ID.
- if sample client is working and you app no, try to debug the sample client win form.
UA-.NETStandard-Samples/Samples at master · OPCFoundation/UA-.NETStandard-Samples · GitHub[
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This should be the link to the samples, hope it help you.