CD Stability VI

Owning Palette: Dynamic Characteristics VIs

Requires: Control Design and Simulation Module

Determines if the input system or poles are stable, unstable, or marginally stable. Wire data to the State-Space Model input to determine the polymorphic instance to use or manually select the instance.

Details  

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 node runs. This input provides standard error in functionality.
	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. This output provides standard error out functionality.

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 node runs. This input provides standard error in functionality.
	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. This output provides standard error out functionality.

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 node runs. This input provides standard error in functionality.
	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. This output provides standard error out functionality.

CD Stability (Complex Roots)

	Poles specifies the poles for which to determine the Stability.
	Discrete System? specifies whether the system is discrete. The default is FALSE, which specifies that the system is continuous.
	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 node runs. This input provides standard error in functionality.
	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. This output provides standard error out functionality.

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.