Conveyor (aka pipeline delay) with constant delay time and no leakage



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The SimpleConveyor (aka pipeline delay) bevhaves as one would expect a conveyor belt to work:  What flows into the SimpleConveyor will flow out after a period given by the parameter delayTime has elapsed. The delayTime will be clipped, so that it can never be smaller than the global parameter modelSettings.dt.


The Conveyor internally uses Modelica's delay() function with a constant time of delay to delay the rate of inflow.


  • All inflows have to go to the inflow port of the Conveyor—no draining is allowed via this port.

  • Since the outflow will be controlled by the Conveyor, →OutflowDynamicStock or →SplitOutflowDynamicStock have to be connected to the outflow port.

  • Using more than one outflow (e.g., SplitOutflowDynamicStock) can be used to model leaking.

  • During the interval [modelSettings.modelStartTime, delayTime] the outflow will simply be the initial value for the stock divided by the delay time.
  • The parameter init in the Advanced tab allows to select →InitializationOptions:
    • FixedValue (default) will initialize the stock according to value given by the parameter initialValue.

    • SteadyState will use Little's Law to determine the equilibrium start value as inflow.rate * delayTime

    • Free tells the solver that it is free in solving the initial value problem using initialValue as startValue.
  • The Conveyor behaves exactly like the PureDelay or the Conveyor when the delay time is constant; the main difference is the absence of time events introduced by the discrete nature of the PureDelay or Conveyor stocks.

  • The Conveyor stock can additionally deal with variable delay times, but is discrete in nature (i.e., it uses time events).

See also

ConveyorPureDelay, DelayFixedDelayInformation

Parameters (4)


Value: modelSettings.init

Type: InitializationOptions

Description: Provide InitializationOptions (Free, FixedValue, SteadyState)


Value: false

Type: Boolean

Description: = true, if a StockInfoOutput should be added to the stock


Value: 0

Type: OutputType

Description: Initial load


Value: 1

Type: Time (s)

Description: Time of residence in the stock

Connectors (6)


Type: RealOutput

Description: Level or rate information


Type: RealOutput

Description: Level or rate information


Type: RealOutput

Description: Level or rate information


Type: StockPort

Description: Inflow port of the stock


Type: StockPort_Special

Description: Special outflow port of the stock (stock sets rate)


Type: StockInfoOutput

Description: Optional StockInfoOutput

Components (3)


Type: ModelSettings

Description: Setting important global variables within a model


Type: DynamicStockInfo

Description: Generate stock information data


Type: ConstantConverterTime

Description: A constant time value is turned into a constant signal

Used in Examples (1)



Modeling a production process