CD Nichols VI

Owning Palette: Frequency Response VIs

Requires: Control Design and Simulation Module

Creates a Nichols plot of the input system for which this VI plots the magnitude, in decibels, of the frequency response against the phase. You can display this data in the CD Nichols Plot indicator. Wire data to the State-Space Model and Frequency Range inputs to determine the polymorphic instance to use or manually select the instance.

This VI converts state-space and zero-pole-gain models into transfer function models before determining the frequency response.

Details  Example

CD Nichols (Frequency Range, State-Space)

	Nichols Graph Reference is a reference to the Nichols Plot on an XY graph. Nichols Graph Reference configures the x-scale, y-scale, and legend properties. If you want to use the default settings or customize the settings for these properties, do not wire a value to this input.
	State-Space Model contains a mathematical representation of and information about the system for which this VI produces a Nichols plot.
	Frequency Range contains the frequency information of the model. Initial frequency is the minimum frequency this VI uses in calculating the frequency response and producing the plots. The default is –1. Final frequency is the maximum frequency this VI uses in calculating the frequency response and producing the plots. The default is –1. Minimum number of points is the minimum number of points this VI uses in calculating the frequency response and producing the plots. The default is 100 points. Frequency Unit specifies the units of frequency, either in Hertz or radians/seconds, to use in calculating the frequency response and producing the plots. 0 Hz 1 rad/s (default)
	error in describes error conditions that occur before this node runs. This input provides standard error in functionality.
	Plots Index is an array of clusters of the following two elements. input # is the index number of the specific input to the system. This VI displays the response to this input in the Nichols Plot on an XY graph. The index is zero-based. output # is the index number of the specific output of the system that this VI displays in the Nichols Plot on an XY graph. The index is zero-based.
	Nichols Plot returns the magnitude (in decibels) of the frequency response of the input system this VI plots against its phase (in degrees). The Plots Index input determines which plots to display on the XY graph. Right-click this terminal on the block diagram and select Create»Indicator from the shortcut menu to display this data in a CD Nichols Plot indicator.
	Nichols Data returns information about the Nichols plot data. To access the Nichols Data, use the CD Get Frequency Response Data VI. Frequency is a 1D-array of frequency values at which this VI calculates the magnitude and phase. Open Loop Gain (dB) is a 3D-array. The ith column in the nth page of the array is the magnitude of the transfer function between the ith output and the nth input. For example, the first two columns of the 0th page will be magnitudes of transfer functions between outputs y0 and y1 and the first input u0. Open Loop Phase (deg) is a 3D-array. The ith column in the nth page of the array is the phase of the transfer function between the ith output and the nth input. For example, the first two columns of the 0th page will be the phase of transfer functions between outputs y0 and y1 and the first input u0. plot type returns the type of the plot. 0 bode-magnitude 1 bode-phase 2 nichols 3 nyquist 4 singular values 5 step 6 impulse 7 initial 8 simulation
	error out contains error information. This output provides standard error out functionality.

CD Nichols (Frequency Range, Transfer Function)

	Nichols Graph Reference is a reference to the Nichols Plot on an XY graph. Nichols Graph Reference configures the x-scale, y-scale, and legend properties. If you want to use the default settings or customize the settings for these properties, do not wire a value to this input.
	Transfer Function Model contains a mathematical representation of and information about the system for which this VI produces a Nichols Plot.
	Frequency Range contains the frequency information of the model. Initial frequency is the minimum frequency this VI uses in calculating the frequency response and producing the plots. The default is –1. Final frequency is the maximum frequency this VI uses in calculating the frequency response and producing the plots. The default is –1. Minimum number of points is the minimum number of points this VI uses in calculating the frequency response and producing the plots. The default is 100 points. Frequency Unit specifies the units of frequency, either in Hertz or radians/seconds, to use in calculating the frequency response and producing the plots. 0 Hz 1 rad/s (default)
	error in describes error conditions that occur before this node runs. This input provides standard error in functionality.
	Plots Index is an array of clusters of the following two elements. input # is the index number of the specific input to the system. This VI displays the response to this input in the Nichols Plot on an XY graph. The index is zero-based. output # is the index number of the specific output of the system that this VI displays in the Nichols Plot on an XY graph. The index is zero-based.
	Nichols Plot returns the magnitude (in decibels) of the frequency response of the input system this VI plots against its phase (in degrees). The Plots Index input determines which plots to display on the XY graph. Right-click this terminal on the block diagram and select Create»Indicator from the shortcut menu to display this data in a CD Nichols Plot indicator.
	Nichols Data returns information about the Nichols plot data. To access the Nichols Data, use the CD Get Frequency Response Data VI. Frequency is a 1D-array of frequency values at which this VI calculates the magnitude and phase. Open Loop Gain (dB) is a 3D-array. The ith column in the nth page of the array is the magnitude of the transfer function between the ith output and the nth input. For example, the first two columns of the 0th page will be magnitudes of transfer functions between outputs y0 and y1 and the first input u0. Open Loop Phase (deg) is a 3D-array. The ith column in the nth page of the array is the phase of the transfer function between the ith output and the nth input. For example, the first two columns of the 0th page will be the phase of transfer functions between outputs y0 and y1 and the first input u0. plot type returns the type of the plot. 0 bode-magnitude 1 bode-phase 2 nichols 3 nyquist 4 singular values 5 step 6 impulse 7 initial 8 simulation
	error out contains error information. This output provides standard error out functionality.

CD Nichols (Frequency Range, Zero-Pole-Gain)

	Nichols Graph Reference is a reference to the Nichols Plot on an XY graph. Nichols Graph Reference configures the x-scale, y-scale, and legend properties. If you want to use the default settings or customize the settings for these properties, do not wire a value to this input.
	Zero-Pole-Gain Modelcontains a mathematical representation of and information about the system for which this VI produces a Nichols plot.
	Frequency Range contains the frequency information of the model. Initial frequency is the minimum frequency this VI uses in calculating the frequency response and producing the plots. The default is –1. Final frequency is the maximum frequency this VI uses in calculating the frequency response and producing the plots. The default is –1. Minimum number of points is the minimum number of points this VI uses in calculating the frequency response and producing the plots. The default is 100 points. Frequency Unit specifies the units of frequency, either in Hertz or radians/seconds, to use in calculating the frequency response and producing the plots. 0 Hz 1 rad/s (default)
	error in describes error conditions that occur before this node runs. This input provides standard error in functionality.
	Plots Index is an array of clusters of the following two elements. input # is the index number of the specific input to the system. This VI displays the response to this input in the Nichols Plot on an XY graph. The index is zero-based. output # is the index number of the specific output of the system that this VI displays in the Nichols Plot on an XY graph. The index is zero-based.
	Nichols Plot returns the magnitude (in decibels) of the frequency response of the input system this VI plots against its phase (in degrees). The Plots Index input determines which plots to display on the XY graph. Right-click this terminal on the block diagram and select Create»Indicator from the shortcut menu to display this data in a CD Nichols Plot indicator.
	Nichols Data returns information about the Nichols plot data. To access the Nichols Data, use the CD Get Frequency Response Data VI. Frequency is a 1D-array of frequency values at which this VI calculates the magnitude and phase. Open Loop Gain (dB) is a 3D-array. The ith column in the nth page of the array is the magnitude of the transfer function between the ith output and the nth input. For example, the first two columns of the 0th page will be magnitudes of transfer functions between outputs y0 and y1 and the first input u0. Open Loop Phase (deg) is a 3D-array. The ith column in the nth page of the array is the phase of the transfer function between the ith output and the nth input. For example, the first two columns of the 0th page will be the phase of transfer functions between outputs y0 and y1 and the first input u0. plot type returns the type of the plot. 0 bode-magnitude 1 bode-phase 2 nichols 3 nyquist 4 singular values 5 step 6 impulse 7 initial 8 simulation
	error out contains error information. This output provides standard error out functionality.

CD Nichols (Frequency Vector, State-Space)

	Nichols Graph Reference is a reference to the Nichols Plot on an XY graph. Nichols Graph Reference configures the x-scale, y-scale, and legend properties. If you want to use the default settings or customize the settings for these properties, do not wire a value to this input.
	State-Space Model contains a mathematical representation of and information about the system for which this VI produces a Nichols plot.
	Frequency Vector specifies information about the frequencies this VI uses to excite the model. Frequency specifies the frequencies this VI uses to excite the model. Frequency Unit specifies the unit of measurement of the Frequency array. 0 Hz—Specifies that the frequency is measured in hertz. 1 rad/s (default)—Specifies that the frequency is measured in radians per second.
	error in describes error conditions that occur before this node runs. This input provides standard error in functionality.
	Plots Index is an array of clusters of the following two elements. input # is the index number of the specific input to the system. This VI displays the response to this input in the Nichols Plot on an XY graph. The index is zero-based. output # is the index number of the specific output of the system that this VI displays in the Nichols Plot on an XY graph. The index is zero-based.
	Nichols Plot returns the magnitude (in decibels) of the frequency response of the input system this VI plots against its phase (in degrees). The Plots Index input determines which plots to display on the XY graph. Right-click this terminal on the block diagram and select Create»Indicator from the shortcut menu to display this data in a CD Nichols Plot indicator.
	Nichols Data returns information about the Nichols plot data. To access the Nichols Data, use the CD Get Frequency Response Data VI. Frequency is a 1D-array of frequency values at which this VI calculates the magnitude and phase. Open Loop Gain (dB) is a 3D-array. The ith column in the nth page of the array is the magnitude of the transfer function between the ith output and the nth input. For example, the first two columns of the 0th page will be magnitudes of transfer functions between outputs y0 and y1 and the first input u0. Open Loop Phase (deg) is a 3D-array. The ith column in the nth page of the array is the phase of the transfer function between the ith output and the nth input. For example, the first two columns of the 0th page will be the phase of transfer functions between outputs y0 and y1 and the first input u0. plot type returns the type of the plot. 0 bode-magnitude 1 bode-phase 2 nichols 3 nyquist 4 singular values 5 step 6 impulse 7 initial 8 simulation
	error out contains error information. This output provides standard error out functionality.

CD Nichols (Frequency Vector, Transfer Function)

	Nichols Graph Reference is a reference to the Nichols Plot on an XY graph. Nichols Graph Reference configures the x-scale, y-scale, and legend properties. If you want to use the default settings or customize the settings for these properties, do not wire a value to this input.
	Transfer Function Model contains a mathematical representation of and information about the system for which this VI produces a Nichols Plot.
	Frequency Vector specifies information about the frequencies this VI uses to excite the model. Frequency specifies the frequencies this VI uses to excite the model. Frequency Unit specifies the unit of measurement of the Frequency array. 0 Hz—Specifies that the frequency is measured in hertz. 1 rad/s (default)—Specifies that the frequency is measured in radians per second.
	error in describes error conditions that occur before this node runs. This input provides standard error in functionality.
	Plots Index is an array of clusters of the following two elements. input # is the index number of the specific input to the system. This VI displays the response to this input in the Nichols Plot on an XY graph. The index is zero-based. output # is the index number of the specific output of the system that this VI displays in the Nichols Plot on an XY graph. The index is zero-based.
	Nichols Plot returns the magnitude (in decibels) of the frequency response of the input system this VI plots against its phase (in degrees). The Plots Index input determines which plots to display on the XY graph. Right-click this terminal on the block diagram and select Create»Indicator from the shortcut menu to display this data in a CD Nichols Plot indicator.
	Nichols Data returns information about the Nichols plot data. To access the Nichols Data, use the CD Get Frequency Response Data VI. Frequency is a 1D-array of frequency values at which this VI calculates the magnitude and phase. Open Loop Gain (dB) is a 3D-array. The ith column in the nth page of the array is the magnitude of the transfer function between the ith output and the nth input. For example, the first two columns of the 0th page will be magnitudes of transfer functions between outputs y0 and y1 and the first input u0. Open Loop Phase (deg) is a 3D-array. The ith column in the nth page of the array is the phase of the transfer function between the ith output and the nth input. For example, the first two columns of the 0th page will be the phase of transfer functions between outputs y0 and y1 and the first input u0. plot type returns the type of the plot. 0 bode-magnitude 1 bode-phase 2 nichols 3 nyquist 4 singular values 5 step 6 impulse 7 initial 8 simulation
	error out contains error information. This output provides standard error out functionality.

CD Nichols (Frequency Vector, Zero-Pole-Gain)

	Nichols Graph Reference is a reference to the Nichols Plot on an XY graph. Nichols Graph Reference configures the x-scale, y-scale, and legend properties. If you want to use the default settings or customize the settings for these properties, do not wire a value to this input.
	Zero-Pole-Gain Modelcontains a mathematical representation of and information about the system for which this VI produces a Nichols plot.
	Frequency Vector specifies information about the frequencies this VI uses to excite the model. Frequency specifies the frequencies this VI uses to excite the model. Frequency Unit specifies the unit of measurement of the Frequency array. 0 Hz—Specifies that the frequency is measured in hertz. 1 rad/s (default)—Specifies that the frequency is measured in radians per second.
	error in describes error conditions that occur before this node runs. This input provides standard error in functionality.
	Plots Index is an array of clusters of the following two elements. input # is the index number of the specific input to the system. This VI displays the response to this input in the Nichols Plot on an XY graph. The index is zero-based. output # is the index number of the specific output of the system that this VI displays in the Nichols Plot on an XY graph. The index is zero-based.
	Nichols Plot returns the magnitude (in decibels) of the frequency response of the input system this VI plots against its phase (in degrees). The Plots Index input determines which plots to display on the XY graph. Right-click this terminal on the block diagram and select Create»Indicator from the shortcut menu to display this data in a CD Nichols Plot indicator.
	Nichols Data returns information about the Nichols plot data. To access the Nichols Data, use the CD Get Frequency Response Data VI. Frequency is a 1D-array of frequency values at which this VI calculates the magnitude and phase. Open Loop Gain (dB) is a 3D-array. The ith column in the nth page of the array is the magnitude of the transfer function between the ith output and the nth input. For example, the first two columns of the 0th page will be magnitudes of transfer functions between outputs y0 and y1 and the first input u0. Open Loop Phase (deg) is a 3D-array. The ith column in the nth page of the array is the phase of the transfer function between the ith output and the nth input. For example, the first two columns of the 0th page will be the phase of transfer functions between outputs y0 and y1 and the first input u0. plot type returns the type of the plot. 0 bode-magnitude 1 bode-phase 2 nichols 3 nyquist 4 singular values 5 step 6 impulse 7 initial 8 simulation
	error out contains error information. This output provides standard error out functionality.

CD Nichols Details

This VI supports delays. Refer to the LabVIEW Control Design User Manual for more information about delays.

Example

Refer to the CDEx Nichols Analysis VI in the labview\examples\Control and Simulation\Control Design\Frequency Analysis directory for an example of using the CD Nichols VI.