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EventFrame trigger based on changing attribute value

henna_lehtola

Dear community members,

Is it possible to define a trigger of an eventframe based on changing attribute value?

Here's my use case:

  • A current eventframe is analysing tank level. The start trigger is Level > 1.
  • The content of the tank are described in attribute Product (which is basically batch name)
  • Sometimes a new Product is added on top of old one. At that point the Level is still > 1 but the Product will change. I would like the ongoing event to end at this point, and a new one to start.

Is there a way to achieve this?

Thanks in advance,

Henna

  • 0

    Hello ​ ,

     

    Yes and no. Asset Analytics gives you the flexibility to define multiple conditions as start- / end-triggers for Event Frames. The challenge really is to create unique trigger conditions. The example you provided does not appear to be clear enough from my point of view.

    I suggest you to watch start watching some of the videos at AVEVA PI System Learning channel. Please watch out for the playlist titled "Asset Framework - Explore metadata, add analytics, and get more out of your PI System"

  • 0

    You may need to configure the event frame analysis' generation mode to something other than the default "Explicit Trigger". This is usually the case when you want event frames that are consecutive or back-to-back, which sounds like your case. In this scenario, the end trigger and start trigger conditions are the same, and we've found this results in zero-duration, instantaneous event frames, rather than the desired, consecutive events.

     

    I would recommend first creating a new PI Point that combines the tank level and product values using a PerformanceEquation analysis (perhaps using the Concat function), and using this PIPoint as the trigger for an event frame analysis with one of the alternative generation modes (Pulse, Step or Step Continuous).