Ticket #89: EoN: Digest NCMD discussion

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  • hermsen

    hermsen - 2020-11-17

    Ensure values which are written by NCMD are later published by an NDATA, if the new value is accepted.

    This is 'by-design' if we implement them accordingly.
    1) If a user application 'setpoint' is changed (written), the change is reflected to the Host.
    2) If a sparkplug Host writes this same 'setpoint' via a NCMD, the user application 'setpoint' is changed and reflected to the Host.

    On writing;
    3) Writing (changing the setpoint value) should always occur in a 'triggered' fashion and never continuously. Both the user application and via NCMD should follow the 'trigger/write once' principle.

     
  • i-campbell

    i-campbell - 2020-11-17

    Implemented in the library.
    Works with the current mqttsparkplugb-example.project, but strings are always overwritten by the application code.

    todo:
    [ ] currently the NCMD payload is limited to 255 bytes. this should be another variable length array for the user to build.
    [x] adjust mqttsparkplugb-example.project to point to new library.
    [x] adjust mqttsparkplugb-example.project. Modify strings so they can demonstrate NCMD
    [x] update https://forge.codesys.com/prj/mqttsparkplugb/home/Add%20SparkplugB%20to%20existing%20CODESYS%20project/ to describe how to set up read tags, write tags and read write tags. (Task moved to example-project issue)
    [x] create a similar issue for implementing DCMD in a similar fashion.

     
  • hermsen

    hermsen - 2020-12-27
    • labels: EoN, NCMD -->
    • status: open --> closed
     

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