Hello,

I assumed the only node without a parent is the Root object.

Unfortunately, in the MDIS companion nodeset, there are several UaMethods that have no parent (and are not used in any UAObjectType)

Example:

<UAMethod BrowseName="1:EnableDisableType" NodeId="ns=1;i=192">
 <DisplayName>EnableDisableType</DisplayName>
 -<References>
  <Reference ReferenceType="HasProperty">ns=1;i=193</Reference>
 </References>
</UAMethod>

It seems, the intention was to have something like a template or prototype, the browse name seems to indicate this.

There is no suited parent in OPC UA Root/Types. Should I ignore these nodes (and their children), or how should I use them?

It was probably not intended in the OPC UA specification to use UAMethods this way.

The objects seen in existing MDIS nodeset files duplicate this definition for every object type and object that references this "method type", although a call to the "type definition" giving the correct object id should have the same effect (or at least could have the same effect) if implemented accordingly.