Create a model named 'archModel', add an
interface, create an interface element with a name 'x', and set the
units for the interface element 'kg'.
modelName = 'archModel';
arch = systemcomposer.createModel(modelName); % Create model
interface = arch.InterfaceDictionary.addInterface('interface'); % Add interface
elem = interface.addElement('x'); % Create interface element
setUnits(elem,'kg'); % Set units for interface element