• Re: “Grit chamber” block in Modelica

    Hello Hector,
    yes it does (should): by reducing the X_ components that contribute to the X_COD.
    I made a calculation table (see image) to show what I mean: do you agree?
  • Re: “Grit chamber” block in Modelica

    Hello Hector,
    in the grit chamber model, the e_inorg fraction of inorganic portion (xi) of the particulate components is removed along with the e_org fraction of the organic portion (1 - xi).
    The calculation of xi is ASM-specific - see image.
    Hope this helps.
  • Re: Question about format in plots

    You are right, Hector  :o
    The option to hide/unhide the line is a hidden property which is not exposed in the Properties pane, but only available via the Extended Editor (an option of the plot menu that is disabled in the standard WEST license).
    All I can suggest (I know it will not be exactly the same) is to set the LineWidth property from 2 to 0 - the line will be very thin, but will not disappear.
    I can try and push this into the next release (Nov 2021)
  • Re: Issues with dynamic simulations of secondary seetling

    Hello Natalia,
    and apologies for the late reply.
    Yes, it looks ok.
    For consistency in nomenclature, I would change Help_X_Layer, into "X_Layer_init" or something similar - but that's of course a detail
  • Re: Question about format in plots

    Hello Hector,
    easy ... when you know the hidden trick  ;)
    You simply cannot do it with the standard type of plot (FastLine): you need to choose "Line" upon creation of the plot.
    And unfortunately, you cannot change the type of a plot once it has been created: all you can do is delete it and create a new one (of type Line).
  • Re: Feeding several SBR tanks - not in parallel

    Hello Viola,
    with reference to your layout, I guess you could connect a timer (3 periods - 3 outputs) to the multi-splitter (Link_1) and set it up as:
    u1 = 1, 0, 0
    u2 = 0, 1, 0
    u3 = 0, 0, 1
    for periods T1, T2, T3.
    In this way the first SBR will receive inflow in period T1, while SBR #2 in period T2 and SBR #3 in period T3.
    Furthermore, you will also have to use the T_launch parameter that effectively delays the time scale of an SBR.
    So SBR #1 will have T_launch=0, SBR #2 T_launch=T1 (relative time 0 of SBR#2 is absolute time 0+T1), SBR #3 T_launch=T1+T2=2 T1 (relative time 0 of SBR#3 is absolute time 0+2T1).
    If your delay time (and feed time) is 2h, then T1=T2=T3 = 2h.
    Hope this helps
  • Re: Lack of correct initialization in some blocks. (As example PI).

    Thank you for your detailed explanation.

    From a technical point of view, what is copied from steady-state to dynamic, is the end state of the former into the initial state of the latter. But this only applies to "derived state variables", i.e. variables defined through a derivative - this is what requires an initial condition.
    Algebraic variables cannot be initialised.
    And parameters of course do not change.

    We will look into another way to implement those controllers and see if what you report can be avoided.
  • Re: Issues with dynamic simulations of secondary seetling

    Hello Natalia,
    what you are trying is of course perfectly possible in WEST, but it will require some (small) coding  ;)
    [list type=decimal]
    [li]you need to define a new CLASS in the library, in which r_H, r_P and v0 are defined as manipulated, interface variables[/li]
    [li]you cannot set specific values for state variables because, by definition, state variables are computed. In particular, you cannot use a flow-through, constant volume model to mimic a batch model. Once again, you need to define a new CLASS in the library[/li]
    Which library are you using? MSL or Modelica?
    If you need help in writing these variants of base models, please let me know.
  • Re: Error to start a simulation

    This looks more like "just" a Warning message, not a true Error message, and your simulation should start - with true errors, the simulation would not start at all.
    Is this the case? And do you get meaningful results, or not?
    It is difficult to exactly say what may have happened. If the error persists, please contact Support (mike@dhigroup.com) and include the actual logbook (save as text / xls file).
  • Re: How to upload the IUWS block in my block library

    The IUWS BlockLib is correct - in fact, there's now a single block library in WEST.
    Which instance have you used for your project? You need to choose IUWS1 or IUWS2 to be able to incorporate IUWS-related block into your process layout.