Xenta 913 is communicating to BACnet MSTP device fine (shows online status), but no data will show up on values page. All of the data will be zeros.
XBuilder does not give you an error or warning of this problem.
Xenta 913, Xenta 731, Xenta 511:B
When using BACnet or Modbus in the 913/731/511:B you can not name the Modbus or BACnet port the same name as any of the devices below it.
For example, if you name your BACnet MSTP port "RTU" and then name the slave device "RTU" the device will show an online status, but you will not see any information on a values page. All of the data will be zeros.
By default, XBuilder attempts to prohibit this from happening by adding a numeric to the end of a new device. So by default the device name would be "RTU 1" and you would have had to rename it to "RTU."
Name the slave device below the BACnet or Modbus port something different than the port itself.