Switch¶

Logical block that writes one of two values to a property of another flowsheet object: when IsOn is True it applies OnValue, otherwise OffValue, to the property SelectedProperty of the object named by SelectedObjectID.

DWSIM.UnitOperations.UnitOperations.Switch
Assembly DWSIM.UnitOperations.dll · Object ← BaseClass ← UnitOpBaseClass ← Switch

At a glance¶

Switch in the example flowsheet

This object has no stream connections; it acts on other objects through their properties.

Example¶

This code runs on every build of this site, and the output below is what it printed.

Python

fs = (Flowsheet.Create("SwitchExample")
      .WithCompound("Water")
      .WithPropertyPackage(PropertyPackages.SteamTables))

feed = fs.AddMaterialStream("Cold water").At(Q.Celsius(20.0), Q.Bar(2.0)).WithMassFlow(Q.KgPerSecond(2.0))
product = fs.AddMaterialStream("Warm water")
duty = fs.AddEnergyStream("Steam duty")
heater = (fs.AddHeater("H-1").WithHeatAdded(Q.Kilowatts(0.0))
          .ConnectFeed(feed).ConnectProduct(product).ConnectEnergyFeed(duty, 1))

builder = fs.AddUnitOperation(ObjectType.Switch, "HS-1")
switch = builder.Object.__implementation__
switch.SelectedObjectID = heater.Object.Name
switch.SelectedProperty = "PROP_HT_3"        # heat added
switch.SelectedPropertyUnits = "kW"
switch.OnValue = 400.0                       # kW with the steam on
switch.OffValue = 0.0

fs.AutoLayout()

switch.IsOn = False
switch.Calculate()                           # what a click does; the solver does not run it
fs.Solve()
q_off, t_off = heater.HeatDutyKW, product.TemperatureK - 273.15

switch.IsOn = True
switch.Calculate()
fs.Solve()
q_on, t_on = heater.HeatDutyKW, product.TemperatureK - 273.15

print(f"Switch off: duty {q_off:.0f} kW, outlet {t_off:.2f} C")
print(f"Switch on:  duty {q_on:.0f} kW, outlet {t_on:.2f} C")
print(f"Temperature rise = {t_on - t_off:.2f} K (m.cp.dT estimate {400.0 / (2.0 * 4.18):.2f} K)")

Output

Switch off: duty 0 kW, outlet 20.00 C
Switch on:  duty 400 kW, outlet 67.84 C
Temperature rise = 47.84 K (m.cp.dT estimate 47.85 K)

DWSIM 10.2.11.0, generated 2026-10-08.

Properties¶

IDs accepted by GetPropertyValue, SetPropertyValue, the sensitivity analysis, the optimizer, the Adjust block and dynamic events. Units are SI; pass another unit system to GetPropertyValue to get them converted.

ID	Name	Unit (SI)	Input
`IsOn`	Switch State (1 = On, 0 = Off)		yes
`OnValue`	Value When On	kW	yes
`OffValue`	Value When Off	kW	yes
`AppliedValue`	Applied Value	kW	result
`SelectedObjectTag`	Switched Object		result
`SelectedProperty`	Switched Property		result
`SelectedPropertyUnits`	Value Units		result

Learn more¶

User guide
- Switch

API members¶

Public members declared by this class. Inherited members are documented on the base classes.

Constructors¶

Switch(): Initializes a new default instance of the Switch class.

Initializes a new default instance of the Switch class.

C#VB.NET

public Switch()

Public Sub New()

Switch(string, string): Initializes a new instance of the Switch class with a name and description.

Initializes a new instance of the Switch class with a name and description.

Parameter	Type	Description
`name`	`String`	The name of this switch.
`description`	`String`	A brief description of this switch.

C#VB.NET

public Switch(string name, string description)

Public Sub New(name As String, description As String)

Properties¶

MobileCompatible: Gets a value indicating whether this switch is compatible with mobile interfaces.

Gets a value indicating whether this switch is compatible with mobile interfaces. Always False.

C#VB.NET

public override bool MobileCompatible { get; }

Public Overrides ReadOnly Property MobileCompatible As Boolean

ObjectClass: Gets or sets the simulation object class category (Switches).

Gets or sets the simulation object class category (Switches).

C#VB.NET

public override SimulationObjectClass ObjectClass { get; set; }

Public Overrides Property ObjectClass As SimulationObjectClass

SupportsDynamicMode: Gets a value indicating whether this switch can run in dynamic simulation mode.

Gets a value indicating whether this switch can run in dynamic simulation mode. Always True.

C#VB.NET

public override bool SupportsDynamicMode { get; }

Public Overrides ReadOnly Property SupportsDynamicMode As Boolean

Methods¶

Calculate(object): Calculates the object.

Calculates the object.

Parameter	Type	Description
`args`	`Object`

C#VB.NET

public override void Calculate(object args = null)

Public Overrides Sub Calculate(args As Object = Nothing)

CloneXML(): Creates a deep copy of this object by round-tripping through XML serialization.

Creates a deep copy of this object by round-tripping through XML serialization.

C#VB.NET

public override object CloneXML()

Public Overrides Function CloneXML() As Object

CloseEditForm(): Closes the editor of this object, if it is open.

Closes the editor of this object, if it is open.

C#VB.NET

public override void CloseEditForm()

Public Overrides Sub CloseEditForm()

DeCalculate(): Decalculates the object.

Decalculates the object.

C#VB.NET

public override void DeCalculate()

Public Overrides Sub DeCalculate()

DisplayEditForm(): Opens the editor of this object.

Opens the editor of this object. A host that has no editor for it does nothing.

C#VB.NET

public override void DisplayEditForm()

Public Overrides Sub DisplayEditForm()

GetDisplayDescription(): Returns the localized description string for this object type.

Returns the localized description string for this object type.

C#VB.NET

public override string GetDisplayDescription()

Public Overrides Function GetDisplayDescription() As String

GetDisplayName(): Returns the localized display name for this object type.

Returns the localized display name for this object type.

C#VB.NET

public override string GetDisplayName()

Public Overrides Function GetDisplayName() As String

GetIconBitmapBytes(): Returns the raw bytes of the icon image for this switch.

Returns the raw bytes of the icon image for this switch.

C#VB.NET

public override byte[] GetIconBitmapBytes()

Public Overrides Function GetIconBitmapBytes() As Byte()

GetProperties(PropertyType): Returns the list of property identifiers available for this switch.

Returns the list of property identifiers available for this switch. The object and property it switches are text and are listed only under ALL.

Parameter	Type	Description
`proptype`	`PropertyType`	The type of properties to retrieve.

C#VB.NET

public override string[] GetProperties(PropertyType proptype)

Public Overrides Function GetProperties(proptype As PropertyType) As String()

GetPropertyDescription(string): Readable names for the property identifiers, which are the .NET property names.

Readable names for the property identifiers, which are the .NET property names.

Parameter	Type	Description
`prop`	`String`

C#VB.NET

public override string GetPropertyDescription(string prop)

Public Overrides Function GetPropertyDescription(prop As String) As String

GetPropertyUnit(string, IUnitsOfMeasure): Returns the unit string for the specified property.

Returns the unit string for the specified property.

Parameter	Type	Description
`prop`	`String`	The property identifier string.
`su`	`IUnitsOfMeasure`	The unit system to use; defaults to SI if not provided.

C#VB.NET

public override string GetPropertyUnit(string prop, IUnitsOfMeasure su = null)

Public Overrides Function GetPropertyUnit(prop As String, su As IUnitsOfMeasure = Nothing) As String

GetPropertyValue(string, IUnitsOfMeasure): Returns the value of the specified property.

Returns the value of the specified property. The on, off and applied values come in the units the target object uses for the switched property in the given unit system (SI when none is given).

Parameter	Type	Description
`prop`	`String`	The property identifier string.
`su`	`IUnitsOfMeasure`	The unit system to use; defaults to SI if not provided.

C#VB.NET

public override object GetPropertyValue(string prop, IUnitsOfMeasure su = null)

Public Overrides Function GetPropertyValue(prop As String, su As IUnitsOfMeasure = Nothing) As Object

SetPropertyValue(string, object, IUnitsOfMeasure): Sets the value of the specified property.

Sets the value of the specified property. The on and off values are taken in the units the target object uses for the switched property in the given unit system (SI when none is given).

Parameter	Type	Description
`prop`	`String`	The property identifier string.
`propval`	`Object`	The new value to assign.
`su`	`IUnitsOfMeasure`	The unit system of the supplied value; defaults to SI if not provided.

C#VB.NET

public override bool SetPropertyValue(string prop, object propval, IUnitsOfMeasure su = null)

Public Overrides Function SetPropertyValue(prop As String, propval As Object, su As IUnitsOfMeasure = Nothing) As Boolean

UpdateEditForm(): Redraws the editor of this object with the current values, if it is open.

Redraws the editor of this object with the current values, if it is open.

C#VB.NET

public override void UpdateEditForm()

Public Overrides Sub UpdateEditForm()

Fields¶

f: The classic (WinForms) editor window open for this switch, if any.

The classic (WinForms) editor window open for this switch, if any. Not saved with the flowsheet.

C#VB.NET

public object f

Public f As Object