This Control Systems App for the HP Prime is used to study the frequency and time domain responses of linear control systems consisting of a process and a controller, as well as stability. The app produces Root Locus Plots as well. • In the frequency domain, open loop response with and without controller and resulting closed loop response (unity feedback loop) can be determined / compared. • In the time domain, the app calculates the open loop and unity feedback loop response to reference changes as well as to disturbances (appearing between controller and process). It also calculates and visualizes the controller output. Input types: Dirac pulse, unit step and ramp.

Although the app type is ‘Parametric’, the app does not rely on the built in HP Prime parametric plot mechanism but on custom plotting routines, including custom mouse movement handling, key press detection and custom soft key menus to accomplish functionality that would not be possible otherwise. The app is entirely menu based (no need to type in commands).

The app takes as input the transfer function of a process as well as the settings of a (PID) controller. Plot types: Nyquist, Nichols, Bode, Time domain response, root locus. • Bode plots show magnitude and phase angle charts on one screen, or you can choose to plot magnitude or phase angle only (enlarged). They plot frequency and magnitude on logarithmic scales. Magnitude can be displayed in dB as well. • Time domain plots show process output, controller output and error signal. • Root locus plots highlight all roots for a given gain and indicate whether the system is stable.

An extensive user guide, including installation instructions, is included in the zipped folder attached.