Connectors and Connector Classes

1 Pin

The by now well-known class Pin is a connector class that can be used to specify the external interface for electrical components that have pins as interaction points.

connector Pin Voltage v; flow Current i; end Pin; // From Modelica.Electrical.Analog.Interfaces
class PinInst Pin pin; // An instance of class Pin end PinInst;

Another way to use the connector Pin is to refer to it from the library using the full path. This method can be used to create instances of all classes that belong to the Modelica library, instead of writing the whole classes every time.

class PinInst Modelica.Electrical.Analog.Interfaces.Pin pin; end PinInst;

A component with an electrical pin connector.

2 Flange

The Flange connector class below, analogous to Pin, is used to describe interfaces for one-dimensional interaction in the mechanical domain by specifying the position s and force f at a point of interaction.

connector Flange Position s; flow Force f; end Flange; // From Modelica.Mechanical.Translational.Interfaces
class FlangeInst Flange flange; // An instance of class Flange end FlangeInst;

A component with a mechanical flange connector.

3 InPort

The connector class InPort when instantiated as inPort is a signal input port that can be connected to receive signals.

connector InPort parameter Integer n = 1; input Real signal[n]; end InPort; // From Modelica.Blocks.Interfaces
class InPortInst InPort inPort[n]; // An instance inPort with one signal (n = 1) end InPortInst;

A component with an inPort connector for signals.

4 Connector Classes

Connector classes often use special types for standard physical quantities represented by Real values, e.g. Voltage. The types Voltage, Current, Position, Force and Distance shown below are just five of the classes available in the Modelica Standard library Modelica.SIunits.

type Voltage = Real(final quantity = "ElectricPotential", final unit = "V");
type Current = Real(final quantity = "ElectricCurrent", final unit = "A");
type Position = Real(final quantity = "Length", final unit = "m");
type Force = Real(final quantity = "Force", final unit = "N");
type Distance = Position(min = 0);