PI Discrete-time PI controller with clocked input and output signals (for periodic and aperiodic systems using the parameterization of the continuous PI controller)
	UnitDelay Delay the clocked input signal for one sample period
	FractionalDelay Delay the clocked input signal for a fractional multiple of the sample period

This information is part of the Modelica Standard Library maintained by the Modelica Association.

This package contains blocks that can be utilized for periodic and non-periodic clocks. These blocks usually utilize the duration of the last interval for the computation of the output signal. For example, the coefficients of the PI block are computed from the coefficients of a continuous-time PI block and from the duration of the last interval.