Siemens SIMATIC S7-1500 Function Manual page 137

OPC UA communication
9.1 What you need to know about OPC UA
Identifier
The Identifier corresponds to the name of the PLC tag in quotation marks. The quotation
mark is the only sign that is not permitted as part of a name in STEP 7. Quotation marks
avoid naming conflicts.
The following example reads the value of the "StartTimer" tag:
The Identifier can consist of several components. The individual components are then
separated by a dot.
The following example reads the "MyDB" array data block completely. This data block
contains an array with ten integer values. All ten values should be read in one pass.
Therefore, "0:9" is entered at the array range.
Example of NodeIds, identifiers and namespaces
The following figure illustrates the relation between NodeIds, identifiers and namespaces: It
is no problem if two nodes have the same identifiers but belong to different namespaces.
STEP 7 (TIA Portal) allows you to easily import namespaces via a server interface.
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Function Manual, 11/2019, A5E03735815-AH
Communication