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Thread: Disconnected Nodes

  1. #1
    Member
    Join Date
    Feb 2014
    Posts
    33

    Disconnected Nodes

    Ran a scenario and received the following message

    ** A special selection set 'Disconnected_Nodes' has been created for all disconnected nodes **

    What could be causing the Disconnected Nodes? They are (1) valve and several junction points. All have piping that is going in the correct direction, diameter, and elevation.

  2. #2
    Hi Mmajner,
    This message and the accompanying disconnected nodes selection set are generated when you run an InfoWater model, and there are elements which the model is unable to connect rest of the network. This disconnection may be caused by one or more closed valves or pipes. I recommend checking for a closed pipe/valve or a check valve that would inhibit flow to these elements. Once you find this closed element and open it, the warning will go away.

  3. #3
    Member
    Join Date
    May 2013
    Posts
    48
    Quote Originally Posted by Mmajner View Post
    Ran a scenario and received the following message

    ** A special selection set 'Disconnected_Nodes' has been created for all disconnected nodes **

    What could be causing the Disconnected Nodes? They are (1) valve and several junction points. All have piping that is going in the correct direction, diameter, and elevation.
    The model YOU created may be all connected... BUT things that happen during the RUN (assuming it is EPS) can result in infoWATER doing something that disconnects a part for the network. Eg a Tank being shut because it is FULL or EMPTY. A look at the engine TXT file [ Report Icon in Run Manager] and a Find [ie CTRL F WARNING or CLOSE] may help find clues.
    Stewart.
    S w Sargent, Services Development Engineer, Marlborough District Council, New Zealand.
    (40 years of modelling in 4 countries, thus far , and still learning)

  4. #4
    Forum Moderator

    Innovyze Employee



    Innovyze Employee



    Join Date
    May 2015
    Posts
    419
    Mmajner,


    There are many things already noted in this forum that can cause a disconnection error. One factor that had not been noted yet that can also potentially create a disconnect error, is if a system has more demand than is supplied and tanks reach 0% full.

    If in a model the input sources are for one reason or another not operating correctly after a while the model tanks will begin to drain. If the program cannot meet the demand with the available supplies at some point the model will usually fail to find a solution and will often give a disconnect error.

    The best way to usually check for this is to do the following:
    1) Add all tanks to the domain ( Domain Manager -> Network-> All Tanks then Add to domain)
    -Click image below for a larger view
    Domain Manager - Select all Tanks.png
    2) Open the output manager and select under the graph Tab Tank Group Graph option (use the domain in the data scope)
    -Click image below for a larger view
    Tank Group Graph on Domain.jpg
    3) When the report pops up switch it so that it is showing % Full for the tanks
    -Click image below for a larger view
    Tanks going Empty.jpg
    This percent full graph for the tanks is a great quick check to see if any tanks are going either 100% full or 0% full. The locations where the tanks are going 0% full are typically where the problems are. However, locations where tanks are going 100% full are also areas where model controls or model control setpoints for the elements that fill the tanks may have an error. If you then check the controls that fill the tanks (pumps or valves) one can often find where missing or incorrect controls have been applied causing the issue.

    If Tanks run empty there is a good chance that the model simulation will not converge and may give a disconnect error.

    Keep this in mind as another "tool for the toolbox" one can use to help diagnose potentially why a Disconnection error is occurring

    Hope this is helpful to you and other modelers.

    Innovyze Support
    Patrick Moore

    Quote Originally Posted by Mmajner View Post
    Ran a scenario and received the following message

    ** A special selection set 'Disconnected_Nodes' has been created for all disconnected nodes **

    What could be causing the Disconnected Nodes? They are (1) valve and several junction points. All have piping that is going in the correct direction, diameter, and elevation.

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