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mamiko · Member 2 Joined: 25 Dec 2017 Posts: 420

Describing local OPC UA tag nodes with a STEP 7 program (value, time stamp, StatusCode)
https://support.industry.siemens.com/cs/document/109820694/
Using the OPC UA instruction "OPC_UA_WriteList", the STEP 7 program lets you write values and supplementary information straight to OPC UA tag nodes of the local OPC UA server. One possible application of this is to modify the time stamp of an OPC UA tag.
The value attribute of an OPC UA tag node has parameters which contain a time stamp in addition to the tag value and StatusCode. The time stamp is only set once an OPC UA client requests this tag. This is done with an OPC UA Read command or as part of a fixed query by an OPC UA subscription.
This means that the OPC UA server sets the time stamp no earlier than a request. The time stamp does not match the actual time at which the event occurred in the source object.

As of firmware V3.0 and TIA Portal V18, the S7-1500 CPUs now offer the capability to assign an OPC UA tag node in the local OPC UA server the following information by means of the program:
Tag value (Value)
Time stamp (SourceTimeStamp)
StatusCode
SourcePicoSeconds
This gives you the ability to determine, besides the actual value, the real time point of a tag change in the OPC UA tag node, and therefore to also make it visible for the OPC UA client.

The following graphic illustrates the principle behind this application.

OPC UA tag nodes with a STEP 7 OPC UA tag nodes with a STEP 7

OPC UA tag nodes with a STEP 7 OPC UA tag nodes with a STEP 7

Basic conditions
The following conditions apply for this function:
A remote OPC UA client has read-only access to this node (access permissions must be set to "RD").
The pertinent OPC UA tags must be modeled with a user-defined server interface.
The server interface must not be mapped with a CPU tag.
The example provides explanations and a function block that intuitively implements the function. You can use it and modify it to suit your own application.

Documentation and sample project
https://support.industry.siemens.com/cs/attachments/109820694/109820694_OPC-UA_SetDataValue_DOC_V1.0_en.pdf
https://support.industry.siemens.com/cs/attachments/109820694/109820694_OPC_UA_WriteList_SetDataValue_PROJ_V1.0.zip

Further informations
Many more examples and information about OPC UA can be found in the link below:
https://support.industry.siemens.com/cs/document/109770435/opc-ua-%e2%80%93-an-overview-of-the-most-important-entries-and-links

https://ulozto.net/tamhle/EOrYqdj0jqkS/

https://teraboxapp.com/s/1GPCp3JoAaq30bKVjHr7lsw