Namespaces are used to generate identifiers which are unique among various naming authorities. NodeIds and BrowseNames of Attributes are identifiers. Nodes in the UA Address Space are definitely identified by the NodeIds. In contrast to the NodeIds, BrowseNames cannot be used to definitely identify Nodes. Different Nodes may share a same BrowseName. BrowseNames are used to create a browse path between two Nodes or define standard Properties.
A server may select the use of a same namespace for NodeIds and BrowseNames. However, for example, when a local server grants standard Properties, their BrowseNames must have a namespace of the standardizing body even though the namespace of the NodeIds reflect other things. All of NodeId for Nodes which are not defined in this specifications must not use the standard namespace.
Table 94 lists mandatory/optional namespaces used by the server.
Table 94 – Namespace used in CSPPlusForMachine Server
|
NameSpace |
Description |
Optional/ Mandatory |
|
htt p://opcfoundation.org/UA/ |
Namespace for NodeIds and BrowseNames defined in the OPC UA specification. This namespace shall have namespace index 0. |
M |
|
Local Server URI |
Namespace for Nodes defined in the local server. This may include types and instances used in a Cspp Machine represented by the server. This namespace shall have namespace index 1. |
M |
|
htt p://opcfoundation.org/UA/DI/ |
Namespace for NodeIds and BrowseNames defined in [OPC 10000-100]. The namespace index is server specific. |
M |
|
htt p://opcfoundation.org/UA/CSPPlusForMachine/ |
Namespace for NodeIds and BrowseNames defined in this specification. The namespace index is server specific. |
M |
|
Vendor specific types and instances |
A server may provide vendor specific types like types derived from CsppMachineType or vendor specific instances of devices in a vendor specific namespace. |
O |
Table 9-5 provides a list of namespaces and their index used for BrowseNames in this specification. The default namespace of this specification is not listed since all BrowseNames without prefix use this default namespace.
Table 9-5 – Namespaces used in this specification
|
Namespace |
Namespace Index |
Example |
|
h tt p://opcfoundation.org/UA/ |
0 |
0:BaseObjectType |
|
htt p://opcfoundation.org/UA/DI/ |
1 |
1:ParameterSet |