Siemens SIMATIC ET 200AL System Manual page 819

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.
Communication
Function Manual, 12/2017, A5E03735815-AF
OPC UA communication
9.1 What you need to know about OPC UA
133