The system is described at a logic level in the system analysis. The functional logic model given can be simulated (e.g. in Matrix-X or Ascet). The same structures are used for the system analysis and the system design (and hence the same DTD as well).
Functional analysis
The functional analysis includes a description of the context, the functions (hierarchical, incl. diagnostic functions, safety functions, etc.) and the information flows (informal). A formal definition, an informal description, application notes and customer-servicing notes are documented for each function (compare Function variants).
Description of time dependencies
The time dependencies can be modeled using RT analysis, status diagrams, Petri networks, etc.