title: OPC-UA whats the difference between "Value" and "Attribute Value"
body: <p>I am actually learning OPC-UA. I am using the c# demo server of LibUA (can be freely downloaded here: <a href="https://github.com/nauful/LibUA" rel="nofollow noreferrer">https://github.com/nauful/LibUA</a>). For each node there, I am seeing two values, one which is constantly changing in the &quot;Data Access View&quot; and one which is static in the &quot;Attributes&quot; view:</p>
  <p><a href="https://i.stack.imgur.com/2g9cQ.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/2g9cQ.png" alt="enter image description here" /></a></p>
  <p>After having a look at the code and reading about how subscriptions work in OPC-UA i understand now why the dynamic value is constantly changing. But what is about this &quot;static&quot; value in the attribute window? Whats the reason for this? Why do we have two values per node, one dynamic and one static?</p>
  <p>The static one is generated by a method called &quot;HandleReadRequestInternal&quot; in the demo server. Whats a &quot;internal&quot; read request? I couldn't find anything about this in the specs. Maybe some expert can help me here to bring some clarity. :)</p>
  <p>Thanks!</p>