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Subsystem Configuration Dialog Box

LabVIEW 2012 Control Design and Simulation Module Help

Edition Date: June 2012

Part Number: 371894G-01

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Requires: Control Design and Simulation Module

Double-click a simulation subsystem or right-click the subsystem and select Configuration from the shortcut menu to display this dialog box.

Use this dialog box to configure the behavior of parameters of a subsystem. You can define the types of inputs and outputs the subsystem accepts, specify initial values, and configure the behavior of enabled and triggered subsystems.

Note  The options that appear in this dialog box can vary depending on the type of the subsystem and whether you are running the subsystem in a Control & Simulation Loop. If you are running the subsystem outside a Control & Simulation Loop, you also can use this dialog box to configure general simulation parameters, such as the ODE Solver the subsystem uses.

This dialog box includes the following components:

  • Polymorphic instance—Specifies the polymorphic instance of the subsystem. This option only appears for polymorphic subsystems. The options that appear in this pull-down menu depend on the functions that the subsystem contains and can include data types, output types, or operations that the subsystem performs.
  • Parameters—Lists all the parameters associated with this subsystem. Select a parameter from this list to configure the parameter. When you select a parameter, the parameter and its associated Parameter source control appear in the Parameter Information section of the configuration dialog box.
  • Preview—Displays a graphical preview, if available, of the subsystem output or configuration.
  • Parameter Information—Contains the parameters you can configure for this subsystem. You must select a parameter from the Parameters list to make that parameter and its associated Parameter source control visible in the Parameter Information section of the configuration dialog box. Additional configuration options can appear in this section and vary depending on the parameter you select.
  • Parameter source—Specifies whether you configure this parameter using the Configuration Dialog Box or a Terminal on the simulation diagram. The default for a required parameter is Terminal. The default for an optional parameter Configuration Dialog Box. If you select Terminal, LabVIEW displays an input for that parameter on the simulation or block diagram, and you can wire values to that input to configure this subsystem programmatically. If you select Configuration Dialog Box, LabVIEW removes that input from the simulation diagram. You then must set the value for this parameter inside the configuration dialog box.
  • Execution Control—Specifies the execution behavior of the subsystem. Select Execution Control from the Parameters list to display this pull-down menu. You can select from the following options:
    • Normal—(Default) Executes the subsystem without checking for an enabled state or waiting for a trigger.
    • Enable—Checks the value wired to the Enable block diagram input before executing the subsystem. The Enable input appears when you select this option.
    • Trigger—Waits for a trigger from the Trigger block diagram input of the Trigger Type you specify before executing the subsystem. The Trigger input appears when you select this option.
    • Enable And Trigger—Checks the value wired to the Enable block diagram input and waits for a trigger from the Trigger block diagram input of the Trigger Type you specify before executing the subsystem. The Enable and Trigger inputs appear when you select this option.
  • Trigger Type—Specifies when to trigger the execution of the subsystem. Set Execution Control to Trigger or Enable And Trigger to enable this pull-down menu. You can select from the following options:
    • Rising—Executes the subsystem when the input value crosses 0 or the Trigger Offset on a positive slope.
    • Falling—Executes the subsystem when the input value crosses 0 or the Trigger Offset on a negative slope.
    • Either—(Default) Executes the subsystem when the input value crosses 0 or the Trigger Offset on a positive or negative slope.
    • None—Does not specify a trigger.
  • Trigger Offset—Specifies the offset from 0 that the subsystem uses when looking for a 0 crossing. The default is 0. Set Execution Control to Trigger or Enable And Trigger to enable this pull-down menu.
  • Hold Previous Output—Indicates the outputs of the subsystem that hold their last known values when the subsystem does not execute. Outputs appear in this list when you set their Disabled Behavior to Hold. Select an output from the Parameters list to configure its Disabled Behavior.
  • Reset to Initial Output—Indicates the outputs of the subsystem that reset to their initial values when the subsystem does not execute. Outputs appear in this list when you set their Disabled Behavior to Reset. Select an output from the Parameters list to configure its Disabled Behavior.
  • Disabled Behavior—Specifies the behavior of the output of a subsystem when the subsystem does not execute. Select an output that appears under Execution Control in the Parameters list to display this option. You can select from the following options:
    • Hold—(Default) Holds the output value to its last known value.
    • Reset—Resets the output value to its initial value.
  • Use Configured Default Value—Specifies to use the value you specify for the value of the subsystem output. If you set Disabled Behavior to Reset, the subsystem always outputs this value when disabled. If you set Disabled Behavior to Hold, the subsystem outputs this value only if the subsystem is disabled on its first execution. Select an output value that appears under Execution Control in the Parameters list to display this option.
  • Initial Time (s)—Specifies the time at which to start the ODE solver. The default is 0 seconds. Select Initial Time(s) under Simulation Parameters in the Parameters list to display this option. Simulation Parameters appears in the Parameters list appears only when you are configuring a subsystem that is outside a Control & Simulation loop.
  • ODE Solver—Specifies the type of ODE solver the simulation uses. Select ODE Solver under Simulation Parameters in the Parameters list to display this option. Simulation Parameters appears in the Parameters list appears only when you are configuring a subsystem that is outside a Control & Simulation loop.

    The type of ODE solver you select determines the simulation parameters you can set. If you select a fixed step-size ODE solver, you can set the Step Size (s). If you select a variable step-size ODE solver, you can set the following parameters: Initial Step Size (s), Minimum Step Size (s), Maximum Step Size (s), Relative Tolerance, and Absolute Tolerance.
  • Nan/Inf Check—Specifies that you want the Control Design and Simulation Module to check the simulation values for not a number (NaN) and infinite (Inf) values. If you place a checkmark in this checkbox and the simulation detects either of these values, the Control Design and Simulation Module stops the simulation. Remove the checkmark from this checkbox to slightly improve simulation performance.

    Select Nan/Inf Check under Simulation Parameters in the Parameters list to display this option. Simulation Parameters appears in the Parameters list appears only when you are configuring a subsystem that is outside a Control & Simulation loop.
  • Step Size (s)—Specifies the interval between the times at which the ODE solver evaluates the model and updates the model output, in seconds. This option is available only if you select a fixed step-size ODE solver. Select Step Size (s) under Simulation Parameters in the Parameters list to display this option. Simulation Parameters appears in the Parameters list appears only when you are configuring a subsystem that is outside a Control & Simulation loop.
  • Discrete Step Size (s)—Specifies the base time step size for the simulation, in seconds. Select Discrete Step Size (s) under Simulation Parameters in the Parameters list to display this option. Simulation Parameters appears in the Parameters list appears only when you are configuring a subsystem that is outside a Control & Simulation loop.
  • Auto Discrete Time—Specifies to automatically calculate the Discrete Step Size (s). Select Auto Discrete Time under Simulation Parameters in the Parameters list to display this option. Simulation Parameters appears in the Parameters list appears only when you are configuring a subsystem that is outside a Control & Simulation loop.

 

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