SI Model Presentation Express VI

Owning Palette: Model Analysis VIs

Installed With: System Identification Toolkit

Plots the Bode, Nyquist, or pole-zero diagram of the transfer function between one response-stimulus pair or response-noise pair of a system model.

Dialog Box Options

Block Diagram Inputs

Block Diagram Outputs

Place on the block diagram

Find on the Functions palette

Dialog Box Options

Parameter	Description
Select Type of Plot	Specifies the type of plot to display and shows a sample result for the selected plot type. Select Type of Plot contains the following options: Bode Plot Nyquist Plot Pole-Zero Plot (default)
Legend of Plots	Displays the plot legend for the selected plot type.
Channel Info	Contains the following options: Type—Specifies whether to compute the Bode, Nyquist, or pole-zero plot of the transfer function between the response and the stimulus or between the response and the noise. You can choose from the following sources: stimulus (default)—Computes the Bode, Nyquist, or pole-zero plot of the transfer function between the response and the stimulus. noise—Computes the Bode, Nyquist, or pole-zero plot of the transfer function between the response and the noise. Input index—Specifies the input channel index of the transfer function. This index is zero-based. Output index—Specifies the output channel index of the transfer function. This index is zero-based.
Frequency Info	Contains the following options: Start frequency—Specifies the normalized start frequency of the data plot. The default is 0.0001. End frequency—Specifies the normalized end frequency of the data plot. The default is 0.5. Num of freq bins—Specifies the number of frequency bins between Start frequency and End frequency for the data plot. The default is 1000. Interval type—Specifies the type of scaling used for the frequency axis, or x-axis. You can choose from the following scaling types: logarithmic (default) linear
Other Info	Contains the following options: Confidence level—Specifies the percentage confidence level of the confidence bound of the frequency response. The default is 99.00. Magnitude unit—Specifies the type of scaling used for the magnitude axis. You can choose from the following scaling types: dB (default) linear

Block Diagram Inputs

Parameter	Description
system model	Contains information about the model structure, nominal or estimated parameters, identification result, and so on. Use the Model Management VIs to retrieve the information system model contains. Note  You can use a customized system model probe to view model information that flows through system model wires when you debug a block diagram created with the System Identification VIs. Right-click a system model wire and select Custom Probe»SI System Model from the shortcut menu to use the system model probe.
error in (no error)	Describes error conditions that occur before this VI or function runs.

Block Diagram Outputs

Parameter	Description
Pole-Zero plot	Returns the pole-zero plot of system model. Pole-Zero plot is a plot of the poles and zeros of the system model on the complex plane, where the real values are on the x-axis, and imaginary values are on the y-axis. Use the SI Pole-Zero Plot Indicator to display the pole-zero plot. real—Returns the real part of zeros and poles. imaginary—Returns the imaginary part of zeros and poles.
Nyquist plot	Returns the Nyquist plot of system model. Nyquist plot returns the imaginary part of the complex frequency response of the input system plotted against its real part. Use the SI Nyquist Plot Indicator to display the Nyquist plot. real—Returns the real part of the frequency response of the system. imaginary—Returns the imaginary part of the frequency response of the system.
Bode magnitude plot	Returns the Bode magnitude plot of system model. Bode magnitude plot is a plot on an XY graph that shows the linear or decibel magnitude of the given model plotted against a set of frequencies. Use the SI Bode Plot Indicator to display the Bode magnitude plot. frequency—Returns the frequency points for the Bode magnitude plot. magnitude—Returns the magnitude for the Bode magnitude plot.
Bode phase plot	Returns the Bode phase plot of system model. Bode phase plot is a plot on an XY graph that shows the phase, in degrees, of the model plotted against a set of frequency values. Use the SI Bode Plot Indicator to display the Bode phase plot. frequency—Returns the frequency points for the Bode phase plot. phase—Returns the phase values of corresponding frequency points.
error out	Contains error information. If error in indicates that an error occurred before this VI or function ran, error out contains the same error information. Otherwise, it describes the error status that this VI or function produces.

This Express VI operates similarly to the following VIs and functions:

SI Bode Plot SI Nyquist Plot
SI Pole-Zero Plot