CD Stability VI

CD Stability (State-Space)

	State-Space Model contains a mathematical representation of and information about the system of which this VI determines stability.
	Tolerance specifies the tolerance this VI uses in determining if a pole is on the imaginary axis in continuous systems or in the unit circle in discrete systems. The default is 1E–8.
	error in describes error conditions that occur before this VI or function runs. The default is no error. If an error occurred before this VI or function runs, the VI or function passes the error in value to error out. This VI or function runs normally only if no error occurred before this VI or function runs. If an error occurs while this VI or function runs, it runs normally and sets its own error status in error out. Use the Simple Error Handler or General Error Handler VIs to display the description of the error code. Use exception control to treat what is normally an error as no error or to treat a warning as an error. Use error in and error out to check errors and to specify execution order by wiring error out from one node to error in of the next node. status is TRUE (X) if an error occurred before this VI or function ran or FALSE (checkmark) to indicate a warning or that no error occurred before this VI or function ran. The default is FALSE. code is the error or warning code. The default is 0. If status is TRUE, code is a nonzero error code. If status is FALSE, code is 0 or a warning code. source specifies the origin of the error or warning and is, in most cases, the name of the VI or function that produced the error or warning. The default is an empty string.
	Stability returns the stability of the system. 0 Stable—For continuous systems, the system is stable if all poles lie on the left half of the complex plane. For discrete systems, the system is stable if all poles lie inside the unit circle. 1 Marginally stable—For continuous systems, the system is marginally stable (or asymptotically stable) if any pole lies on the imaginary axis. For discrete systems, the system is marginally stable (or asymptotically stable) if any pole lies in the unit circle. 2 Unstable—For continuous systems, the system is unstable if any pole lies on the right half of the complex plane or if the multiplicity of any pole on the imaginary axis is greater than one. For discrete systems, the system is unstable if any pole lies outside the unit circle or if the multiplicity of any pole on the unit circle is greater than one. 3 undetermined (default)—The VI cannot determine the stability of the system because there is an error or the system is empty.
	Poles returns the poles, which this VI uses to determine the type of Stability, of the input system.
	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. Right-click the error out front panel indicator and select Explain Error from the shortcut menu for more information about the error. status is TRUE (X) if an error occurred or FALSE (checkmark) to indicate a warning or that no error occurred. code is the error or warning code. If status is TRUE, code is a nonzero error code. If status is FALSE, code is 0 or a warning code. source describes the origin of the error or warning and is, in most cases, the name of the VI or function that produced the error or warning.

CD Stability (Transfer Function)

	Transfer Function Model contains a mathematical representation of and information about the system of which this VI determines stability.
	Tolerance specifies the tolerance this VI uses in determining if a pole is on the imaginary axis in continuous systems or in the unit circle in discrete systems. The default is 1E–8.
	error in describes error conditions that occur before this VI or function runs. The default is no error. If an error occurred before this VI or function runs, the VI or function passes the error in value to error out. This VI or function runs normally only if no error occurred before this VI or function runs. If an error occurs while this VI or function runs, it runs normally and sets its own error status in error out. Use the Simple Error Handler or General Error Handler VIs to display the description of the error code. Use exception control to treat what is normally an error as no error or to treat a warning as an error. Use error in and error out to check errors and to specify execution order by wiring error out from one node to error in of the next node. status is TRUE (X) if an error occurred before this VI or function ran or FALSE (checkmark) to indicate a warning or that no error occurred before this VI or function ran. The default is FALSE. code is the error or warning code. The default is 0. If status is TRUE, code is a nonzero error code. If status is FALSE, code is 0 or a warning code. source specifies the origin of the error or warning and is, in most cases, the name of the VI or function that produced the error or warning. The default is an empty string.
	Stability returns the stability of the system. 0 Stable—For continuous systems, the system is stable if all poles lie on the left half of the complex plane. For discrete systems, the system is stable if all poles lie inside the unit circle. 1 Marginally stable—For continuous systems, the system is marginally stable (or asymptotically stable) if any pole lies on the imaginary axis. For discrete systems, the system is marginally stable (or asymptotically stable) if any pole lies in the unit circle. 2 Unstable—For continuous systems, the system is unstable if any pole lies on the right half of the complex plane or if the multiplicity of any pole on the imaginary axis is greater than one. For discrete systems, the system is unstable if any pole lies outside the unit circle or if the multiplicity of any pole on the unit circle is greater than one. 3 undetermined (default)—The VI cannot determine the stability of the system because there is an error or the system is empty.
	Poles returns the poles, which this VI uses to determine the type of Stability, of the input system.
	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. Right-click the error out front panel indicator and select Explain Error from the shortcut menu for more information about the error. status is TRUE (X) if an error occurred or FALSE (checkmark) to indicate a warning or that no error occurred. code is the error or warning code. If status is TRUE, code is a nonzero error code. If status is FALSE, code is 0 or a warning code. source describes the origin of the error or warning and is, in most cases, the name of the VI or function that produced the error or warning.

CD Stability (Zero-Pole-Gain)

	Zero-Pole-Gain Model contains a mathematical representation of and information about the system of which this VI determines stability.
	Tolerance specifies the tolerance this VI uses in determining if a pole is on the imaginary axis in continuous systems or in the unit circle in discrete systems. The default is 1E–8.
	error in describes error conditions that occur before this VI or function runs. The default is no error. If an error occurred before this VI or function runs, the VI or function passes the error in value to error out. This VI or function runs normally only if no error occurred before this VI or function runs. If an error occurs while this VI or function runs, it runs normally and sets its own error status in error out. Use the Simple Error Handler or General Error Handler VIs to display the description of the error code. Use exception control to treat what is normally an error as no error or to treat a warning as an error. Use error in and error out to check errors and to specify execution order by wiring error out from one node to error in of the next node. status is TRUE (X) if an error occurred before this VI or function ran or FALSE (checkmark) to indicate a warning or that no error occurred before this VI or function ran. The default is FALSE. code is the error or warning code. The default is 0. If status is TRUE, code is a nonzero error code. If status is FALSE, code is 0 or a warning code. source specifies the origin of the error or warning and is, in most cases, the name of the VI or function that produced the error or warning. The default is an empty string.
	Stability returns the stability of the system. 0 Stable—For continuous systems, the system is stable if all poles lie on the left half of the complex plane. For discrete systems, the system is stable if all poles lie inside the unit circle. 1 Marginally stable—For continuous systems, the system is marginally stable (or asymptotically stable) if any pole lies on the imaginary axis. For discrete systems, the system is marginally stable (or asymptotically stable) if any pole lies in the unit circle. 2 Unstable—For continuous systems, the system is unstable if any pole lies on the right half of the complex plane or if the multiplicity of any pole on the imaginary axis is greater than one. For discrete systems, the system is unstable if any pole lies outside the unit circle or if the multiplicity of any pole on the unit circle is greater than one. 3 undetermined (default)—The VI cannot determine the stability of the system because there is an error or the system is empty.
	Poles returns the poles, which this VI uses to determine the type of Stability, of the input system.
	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. Right-click the error out front panel indicator and select Explain Error from the shortcut menu for more information about the error. status is TRUE (X) if an error occurred or FALSE (checkmark) to indicate a warning or that no error occurred. code is the error or warning code. If status is TRUE, code is a nonzero error code. If status is FALSE, code is 0 or a warning code. source describes the origin of the error or warning and is, in most cases, the name of the VI or function that produced the error or warning.

CD Stability Details

This VI does not support delays unless the delays are part of the mathematical model that represents the dynamic system. To account for the delays when calculating the dynamic characteristics of a system, you must incorporate the delays into the mathematical model of the dynamic system using the CD Convert Delay with Pade Approximation VI (continuous models) or the CD Convert Delay to Poles at Origin VI (discrete models). Refer to the LabVIEW Control Design User Manual for more information about delays and the limitations of Pade Approximation.