CD Get Frequency from Frequency Data VI

Owning Palette: Frequency Response VIs

Requires: Control Design and Simulation Module

Gets the frequency of a system at a specific point by searching Frequency Data for specific values. This VI determines the frequency using Magnitude and Phase for Bode plots, Real and Imaginary for Nyquist plots, and Open Loop Gain and Open Loop Phase for Nichols plots. This VI is especially useful for Nyquist and Nichols plots, where frequency is not obvious, but rather implicit in the plot.

This VI calls the CD Get Frequency Response Data (Input-Output Pair) function to get values from the system. Frequency Data can be Bode, Nichols, or Nyquist data.

Note  The search values you specify must match the values in Frequency Data exactly, or the Frequency output returns 0.

	Frequency Data contains information about the frequency response of a model. You can use the CD Bode VI, CD Nichols VI, or CD Nyquist VI to get the data to wire to this input. Frequency is the frequency response vector at which this VI plots the real versus imaginary parts of the transfer function H(w). Open Loop Gain (dB) is a 3D-array that contains data about the frequency response of the real part of the elements in the matrix H(w). 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 that contains data about the frequency response of the imaginary part of the elements in the matrix H(w). 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 specifies the type of plot of the data. 0 bode-magnitude (default) 1 bode-phase 2 nichols 3 nyquist 4 singular values 5 step 6 impulse 7 initial 8 simulation
	Magnitude/Real/Open Loop Gain specifies the magnitude, real part, or open loop gain of the element for which you want to get the frequency.
	Phase/Imaginary/Open Loop Phase specifies the phase, imaginary part, or open loop phase of the element for which you want to get the frequency.
	error in describes error conditions that occur before this node runs. This input provides standard error in functionality.
	Input specifies the index number for the input from which to begin searching.
	Output specifies the index number for the output from which to begin searching.
	Frequency returns the frequency of the system at the Magnitude/Real/Open Loop Gain and Phase/Imaginary/Open Loop Phase you specify.
	error out contains error information. This output provides standard error out functionality.