Every Node has the following
Attributes
:
• an
ID
(unique)
• a
Class
(what type of node it is)
• a
BrowseName
(a string for machine use)
• a
DisplayName
(a string for human use)
Figure 23. OPC UA address space
Shown on the left-hand side of the figure is the
Address Space
(collection of information that the server makes available to clients)
of the OPC server found at
opc.tcp://192.168.15.4:16664
.
Selected is a node with NodeID
ns=1;i=118
, BrowseName=
1:SJA1105
and of NodeClass
Object
.
The full path of the selected node is
0:Root,0:Objects,1:SJA1105
.
7.3 Node Namespaces
Namespaces
are the means for separating multiple Information Models present in the same Address Space of a server.
• Nodes that do not have the
ns=
prefix as part of the NodeID have an implicit
ns=0;
prefix (are part of the namespace
zero
).
• Nodes in
namespace * 0
have NodeID’s pre-defined by the OPC UA standard. For example, the
0:Server
object, which
holds self-describing information (capabilities, diagnostics, and vendor information), has a predefined NodeID of
ns=0;i=2253;
.
It is considered a good practice to not alter any of the nodes exposed in the
namespace * 0
.
NXP Semiconductors
OPC UA
Open Industrial User Guide, Rev. 1.8, 05/2020
User's Guide
90 / 199
