Duration Calculus, a real-time interval logic, is used to specify requirements for a control task, exemplified by a steam boiler. The same formalism is used to refine requirements to a functional design. Functional designs use a subset of Duration Calculus formulas which through a suitable transformation links to an event and action based formalism. Finally, components in the resulting design for a distributed architecture are transformed to occam-like programs. The presented approach links formalisms from a top level requirements notation down to programs together in a mathematically coherent development trajectory.