Dynamic Behavior Flashcards
The ratio of the final change in PV output to the final change in input
K (steady-state gain)
It defines the speed of the response. For 1st order processes, after τ seconds, the PV output is 63.2% of the way to its final value.
τ (time constant)
In a ramp response, the exponential term, influences the response mostly at the _____ only
onset
Time it takes to reach the new steady-state for the first time
Rise time
Computed as a/b
Overshoot
Time it takes to reach the first maximum value
Time to first peak
Time between two successive peaks in the response
Period
Computed as c/a
Decay ratio
s-values where T.F. is infinity
Poles
s-values where T.F is zero
Zeros
A plot of the complex s-plane showing the location of poles and zeros. The abscissa is the real part of s, and the ordinate is the imaginary part of s
Pole-zero plot
Processes whose transfer functions have m=n.
Lead-lag process
In lead-lag process, the initial value of their step response can be non-zero, hence, they can have a _____
jump discontinuity
If the pole-zero of a process T.F contains a pair of poles equidistant from the x-axis, they are complex conjugate pairs.
Oscillatory behavior
A right half-plane zero produces an initial output response that goes opposite to the direction of the input.
Inverse response
The presence of poles at the origin indicate an integrating process. This means that the output response is bounded for open inputs.
Integrators
The area under the input is continuously increasing with time
Open input
The area under the input is finite with time
Closed input
Uses the concept of BIBO (bounded input, bounded output).
Stability
If the process T.F has right half-plane poles, an _____ response will arise regardless of input.
Unstable
The signal values does not go beyond a certain region all the time
Bounded input
The signal eventually decreases or increases unceasingly with time.
Unbounded inputs
Means that whether we apply an input to the system now or θ seconds from now, the output will be identical except for a time delay of θ seconds
Time-invariance
Rule use in approximating higher-order T.F using time delay
Skogestad’s half-rule
