This simulation plots the time-domain response of a system with a step input of unity. Select either a first-order plus dead time (FOPDT) model or a second-order plus dead time (SOPDT) model. Set the time constant τ to change how quickly the system reaches a new steady state, the process gain K to change how aggressively the system responds to the unity step input and the dead time Θ that delays the system response by a value of Θ. For the second-order process, change the damping coefficient ξ with a slider. The damping coefficient is a measure of the magnitude of damping, which affects the degree of oscillation in the response. Dimensionless time is used.