Siemens SIMATIC HMI Series System Manual page 75

OPC tags: Time stamp for Alarm Logging and Tag Logging
If messages are triggered by OPC tags, the message time stamp is used by the OPC server,
comparably to chronological reporting.
For Tag Logging the time stamp is generated by the Tag Logging server.
OPC UA: Displaying OPC UA tags
Tags created with a WinCC version older than V7.4 are shown as imported in the "Symbols"
view of the Configuration Studio.
However, in this case the tags of the type "Raw data" are not shown as imported. The column
"Access" is not available, although these tags have been correctly created in the Tag
Management.
Reimport these tags and delete the incorrectly displayed tags in the Configuration Studio.
OPC Data Access
When running the OPC DA server on a WinCC client:
During the connection establishment of the OPC client, the WinCC server with which the OPC
client exchanges data must be in Runtime. If the WinCC server is deactivated, not all properties
of the items will be provided.
Since the display of data types in OPC Item Manager requires a lot of time, the display should
be turned off if it is not needed.
OPC XML Data Access
Display of newly created tags
When you create new tag folders with new tags in Runtime in the WinCC project, the tag folders
and the tags will not become visible on the OPC client until you have restarted WinCC Runtime
on the OPC client system. Make sure that "OPCTags" are no longer open on the OPC client.
Add Tags
If you want to add tags with the OPC Item Manager, then WinCC Runtime will have to be
enabled on the OPC server.
Authentication method
XML DA Web service is installed using WinCC Setup with the "Integrated Windows
Authentication" authentication method. The WinCC OPC XML client supports this method. For
this, the user account under which the OPC Client runs must be known to the XML server
computer.
Upgrade installation: Setting up a WinCC OPC XML server
After an upgrade installation, in Computer Management, for the "Internet Information Services
(IIS) Manager", under "Application Pools" for "WinCC-OPC-XML" you have to change the
Microsoft .Net Framework version from V2.0 to V4.0.
WinCC: General information and installation
System Manual, 02/2017, A5E40840020-AA
WinCC Release Notes
2.3 Notes on WinCC
75