Hi @JimWalls,
The error message below has occurred because the “BACnet/MSTP” tag does not exist within your project. To ensure accuracy, please use the API to create the GetDataEx statements: Link
Note: Please see steps 5 - 9 mentioned in the link above.
Regarding (Q2), the correct entry would be a valid tag name within your device, it may appear as in the example image below:
However, as noted it is best to use the API to select tags as explained in the post linked in my first paragraph. The API (e.g., “GET / SET FN…” button) would also allow you to set the device name as referenced in (Q3).