.ModelicaAdditions.Blocks.Discrete

Information

This package contains discrete control blocks with fixed sample period. Every component of this package is structured in the following way:

1. A component has continuous real input and output signals.
2. The input signals are sampled by the given sample period defined via parameter samplePeriod. The first sample instant is defined by parameter startTime.
3. The output signals are computed from the sampled input signals.

A sampled data system may consist of components of package Discrete and of every other purely algebraic input/output block, such as the components of packages Modelica.Blocks.Math, Modelica.Blocks.Nonlinear or Modelica.Blocks.Sources.

This package contains the following components:

   Sampler           Ideal sampling of continuous signals
   ZeroOrderHold     Zero order hold of a sampled-data system
   FirstOrder        Discrete-time approximation of first order system
   UnitDelay         Delay input signal by one sampling period
   TransferFunction  Discrete-time approximation of transfer function
   StateSpace        Discrete-time approximation of state space system
   TriggeredSampler  Triggered sampling of continuous signals
   TriggeredMax      Compute maximum, absolute value of continuous signal
                     at trigger instants

This package is not part of the Modelica standard library, because it is planned to realize an improved package with vectorized components (similiar to the Modelica.Blocks.Continuous package) and several different ways to define the sample period. Especially, the sample period may optionally be defined via an outer parameter in a higher level. This features cannot be provided in a satisfactory way in Modelica version 1.3, due to some missing properties of the replaceable attribute.

Main Author:

Martin Otter
Deutsches Zentrum für Luft und Raumfahrt e.V. (DLR)
Institut für Robotik und Mechatronik
Postfach 1116
D-82230 Wessling
Germany
email: Martin.Otter@dlr.de

Release Notes:

• October 21, 2002 by Martin Otter:
  New components TriggeredSampler and TriggeredMax added.
• June 18, 2000 by Martin Otter:
  Realized based on a corresponding library of Dieter Moormann and Hilding Elmqvist.

Copyright © 2000-2002, DLR.

The Discrete package is free software; it can be redistributed and/or modified under the terms of the Modelica license, see the license conditions and the accompanying disclaimer in the documentation of package Modelica in file "Modelica/package.mo".

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