4 Replies Latest reply on Jan 16, 2018 3:52 PM by dwightwhe RSS
    dwightwhe Explorer

    Getting logged property values from value stream


    I have a Thing with some logged properties. Properties are defined in the ThingTemplate as logged, not persistent, not read-only. I also tried direct logged properties with the Thing not from the ThingTemplate.

    I have a ValueStream created and have it attached to the Thing. Property values change regularly on a Timer event (and manually).


    How can I access the logged values for the logged properties either from the value stream or the thing itself? I don't see any ValueStream services for accessing the stream values. The documentation does not speak to how to get value stream data. What do I miss?


    Calling service GetLoggedProperties on the Thing returns the logged properties, so this is OK.

    Calling service GetPropertyLogging on the direct properties returns true, on a inherited properties from the template returns an error.




    Much appreciated!

      • Getting logged property values from value stream
        adam Creator

        Hi Dwight,


        I'm working on getting some documentation together for the


        of a

        Value Stream

        . For the time being, I can tell you the


         for retrieving logged property values are on the


         with the properties being logged. There are a number of


         for querying data for each basetype including





        to name a few.

        I'll have to look into the error you're getting when calling




         inherited from a


        . What is the error message?



        • Getting logged property values from value stream
          dwightwhe Explorer

          Hi Adam,

          thanks a lot. The QueryTypePropertyHistory Services on the Thing with the logged property work for me.

          Regarding the observed error (is not a blocker for us): When I call Thing.GetPropertyLogging with a property inherited from the ThingTemplate, I get:


          Property does not exist

          When I make this call with a property that I define directly with the Thing, I get a normal result. Independent of that, I can query the property history for all logged properties. Thing.GetLoggedProperties also returns all inherited and direct properties just fine.