Company Events Academic Community Support Solutions Products & Services Contact NI MyNI

Discrete Delay Function

LabVIEW 2012 Control Design and Simulation Module Help

Edition Date: June 2012

Part Number: 371894G-01

»View Product Info

Owning Palette: Discrete Linear Systems Functions

Requires: Control Design and Simulation Module

Delays the input by the number of discrete time steps you specify for the delay parameter.

Details  Example

Dialog Box Options
Block Diagram Inputs
Block Diagram Outputs

Dialog Box Options

ParameterDescription
Polymorphic instanceSpecifies whether this function is Scalar or Vector. The default value is Scalar.
ParametersLists all the parameters associated with this function. 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.
PreviewDisplays a graphical preview, if available, of the function output or configuration.
Parameter InformationContains the parameters you can configure for this function. 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.
Parameter sourceSpecifies whether you configure this parameter using the Configuration Dialog Box or a Terminal on the simulation diagram. The default value is Configuration Dialog Box. If you select Terminal, LabVIEW displays an input for that parameter on the simulation diagram, and you can wire values to that input to configure this function 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.
maximum delayControls the maximum value possible for delay. If maximum delay is –1, the maximum delay is equal to the value of delay at the start of the simulation.
delaySpecifies the number of discrete time steps to delay the input signal. The delay must be greater than zero and less than or equal to the maximum delay, or LabVIEW returns error –2322.
sample period (s)Specifies the length of the discrete time step, in seconds, of this function. If you enter a value of -1, this function inherits the discrete time step you specify for the simulation diagram. Otherwise, the value of sample period (s) must be a multiple of the discrete time step you specify for the simulation diagram. The default value of sample period (s) is -1.
sample skew (s)Specifies the length of time by which you want to delay the execution of this function. The default value is 0. The value of this parameter must satisfy the following relationship:

0 ≤ sample skew (s)sample period (s)
initial conditionSpecifies the output value at the first time step. The default value is 0.

Block Diagram Inputs

ParameterDescription
maximum delayControls the maximum value possible for delay. If maximum delay is –1, the maximum delay is equal to the value of delay at the start of the simulation.
delaySpecifies the number of discrete time steps to delay the input signal. The delay must be greater than zero and less than or equal to the maximum delay, or LabVIEW returns error –2322.
sample period (s)Specifies the length of the discrete time step, in seconds, of this function. If you enter a value of -1, this function inherits the discrete time step you specify for the simulation diagram. Otherwise, the value of sample period (s) must be a multiple of the discrete time step you specify for the simulation diagram. The default value of sample period (s) is -1.
sample skew (s)Specifies the length of time by which you want to delay the execution of this function. The default value is 0. The value of this parameter must satisfy the following relationship:

0 ≤ sample skew (s)sample period (s)
initial conditionSpecifies the output value at the first time step. The default value is 0.
inputSpecifies the input to the function.

Block Diagram Outputs

ParameterDescription
outputReturns the output of the function.

Discrete Delay Details

The following equations define the output of this function.

y(0) = initial condition

y(tk) = u(tk – 1)

whereu is the input
y is the output
tk = initial time + sample skew (s) + k * delay * sample period (s), for k = 0, 1, 2, …

Feedthrough Behavior

For this function, the input input has indirect feedthrough to the output output. All other input/output pairs have direct feedthrough behavior.

Example

Refer to the SimEx discrete unit delay VI in the labview\examples\Control and Simulation\Simulation\Discrete Linear directory for an example of using the Discrete Delay VI.


 

Your Feedback! poor Poor  |  Excellent excellent   Yes No
 Document Quality? 
 Answered Your Question? 
Add Comments 1 2 3 4 5 submit