Editing Modelica (section)

===Connectors describing physical interaction===

The interaction of a component to other components is defined by physical ports, called '''connectors''', e.g., an electrical pin is defined as

<syntaxhighlight lang=modelica>
connector Pin "Electrical pin"
   Voltage      v "Potential at the pin";
   flow Current i "Current flowing into the component";
end Pin;
</syntaxhighlight>

When drawing connection lines between ports, the meaning is that corresponding connector variables without the "flow" prefix are identical (here: "v") and that corresponding connector variables with the "flow" prefix (here: "i") are defined by a zero-sum equation (the sum of all corresponding "flow" variables is zero). The motivation is to automatically fulfill the relevant balance equations at the infinitesimally small connection point.