ControlDraw was originally written to address the requirement for control engineers to produce precise specifications for process and manufacturing control systems. Such specifications can be much more than requirements specifications. They can specify for example the detailed functions that are required to make the plant function.It enables Control Systems engineers and makes possible the production of very tight specifications for complex systems.
It is also extendable into the detailed design of the target systems, and some ControlDraw users develop the models into models that include detailed design data that is not needed in a requirement specification but is needed in the system.
For example, a Functional Requirement might specify a set point for a measurement whereas the system also needs to be configured with dozens of other settings such as 3 other set points, enable bits for each, and mode bits. ControlDraw models for the requirements need not contain this design data whilst the design model should.