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Command object - ActionCommand Null values

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Nelson V.
2015-06-02
2015-06-05
  • Nelson V.

    Nelson V. - 2015-06-02

    From the latest bacnet4j code implementation, I can see that it's only possible to set / read ActionCommand Null values, to the Commandable object / properties, which means only AO, AV, BO, BV, MO, MV and Access-Door objects / present-value property.

    I'm currently working with some devices that allow Null values to be set on ActionCommand value settings for any object type so I was wondering if this was a bad standard interpretation from the device implementation.
    From the readings of the Standards (I took a look both on 135/2004 and 135/2012), and I could see that the list of Commandable objects has increased but the doubt remains: should or shouldn't it be possible that the ActionCommand values maybe Null for non-Commandable object / properties.

    Can somebody please enlighten me about this subject?

    Thanks

     
  • Nelson V.

    Nelson V. - 2015-06-02

    Hello Matthew,

    Thank you for your answer.

    I was looking at that code version you mentioned already. The issue that I see is in the Encoding.java file, around line 337. If I would bypass that "if condition" and treat all values as Ambiguous, then I would have no problem reading these ActionCommand with Null values, but I don't want to do something like that if it goes against the standard definition.

    So, I will pose this question to the BACNet list, as you recommended, but anyway, would you care to give also your opinion on this subject?

    Thanks again

     
  • Matthew Lohbihler

    My opinion is Null is ok as a value if Null is a permitted value for the referenced object type and property. If this is accurate, then i think the code is too. In what cases do you want to use Null? I.e. what object type / property combinations?

     
  • Nelson V.

    Nelson V. - 2015-06-04

    Hi Matthew,

    Again, thank you for your answer.

    The question is not that I want to set a specific object or property to Null, but the devices that I'm working with, allow the setting of Null values in ActionCommands for any Object Type / Present-Value property.

    So, if I read the Action data from these devices with current bacnet4j implementation, the Actions which have these Null values for objects like Analog Inputs, Blind-Outputs, etc (which are not commandable), will not be decoded, and the Action data will not be available.

    But again, I don't want to do any sort of fix, without having some other opinions (I'm still waiting for inputs from the Bacnet-L list) which clear this point. If it is considered as valid, by the standard rules, to set these Null values also for non-commandable objects / properties, then I will need to do something about it, else I will not.

    Thanks again

     
  • Matthew Lohbihler

    Gotcha. I believe it is incorrect for those devices to be so lenient. BTW, i did not see a message from you on the mailing list.

     
    • Nelson V.

      Nelson V. - 2015-06-05

      It seems that I'm still on the BACNet-L 'subscription approval' waiting list...
      I hope it don't take too long, else I'll be stuck.

       

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